Chemical and biological combined treatment for the sugarcane vinasse: Selection of parameters and performance studies

Chemical and biological combined treatment for the sugarcane vinasse: Selection of parameters and performance studies | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Chemical and biological combined treatment for the sugarcane vinasse: Selection of parameters and performance studies Wei-Chin Kee, Yee-Shian Wong, Soon-An Ong, Nabilah Aminah Lutpi, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-2007267/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 21 Apr, 2023 Read the published version in Environmental Science and Pollution Research → Version 1 posted 6 You are reading this latest preprint version Abstract Sugarcane vinasse has been widely reported due to the improper management that pollutes the environment. In this study, a combined coagulation and sequencing batch biofilm reactor (SBBR) seems to be a novel improvement for the treatment of sugarcane vinasse. This research focused on the optimal conditions of coagulation and SBBR and determined the abatement efficiency of sugarcane vinasse in combined sequential wastewater treatment. The coagulation process destabilizes the colloids in the aggregation and separates the supernatant by sedimentation and filtration, resulting in the maximum COD reduction (79.0 ± 3.4%) and decolorization efficiency (94.1 ± 1.9%) under the optimum conditions. Sequencing batch reactor (SBR) is a fill-and-draw activated sludge system, whereas SBBR is an integrated SBR that suspends activated sludge and connects growth processes into a biocarrier-filled system. SBBR showed great synergistic degradability, decreasing 86.6 ± 4.3% COD concentration and 94.6 ± 3.8% decolorization at 3.0 g/L of substrate loading concentration. Furthermore, kinetic studies of SBBR revealed that the first-order kinetic model was the best fitting model. The SBBR reaction was further investigated by ultraviolet-visible spectrophotometry (UV–Vis). Then, SBBR followed by the coagulation process (SBBR–CP) achieved 97.5% of COD reduction and 99.4% of decolorization, which was better than the coagulation process followed by SBBR (CP–SBBR). This finding provides new insight into developing efficient combined sequential wastewater treatments in sugarcane vinasse. Coagulation Combined processes Industrial effluent Sequencing batch biofilm reactor Sugarcane vinasse Wastewater treatment Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 1 Introduction Sugarcane vinasse is one of the most generated wastewaters in the bioethanol distillery, and one liter of bioethanol production could generate around nine to fourteen liters of sugarcane vinasse (España-Gamboa et al. 2011 ). Vinasse contains a lot of harmful substances, such as phenols, polyphenols, and heavy metals, as well as significant levels of organic content and dissolved solids. Its characteristics of being acidic (pH of 4.30–4.55), dark brown, and having a high chemical oxygen demand (COD) concentration (28.5–85.0 gCOD/L) are necessary to be a concern since the phytotoxic and recalcitrant compounds in the sugarcane vinasse could negatively affect the organisms at disposal sites (Chai et al. 2021 ; Kiani Deh Kiani et al. 2021; Takeda et al. 2022 ). Disposing of untreated/partially treated vinasse on land or groundwater could cause a profound environmental impact. Thus, the bioethanol industry has adopted some technological applications such as fertigation (Carpanez et al. 2022), physico-chemical (Hoarau et al. 2018), and biological treatments (Silva et al. 2021). Fertigation using sugarcane vinasse is commonly applied due to the increase of crop productivity without complex technologies for its management; however, its uncontrolled practice can cause soil salinization, water sources contamination, and bad odors release (Fuess and Garcia 2014). The coagulation/flocculation method is the most common chemical treatment technology, especially as a pre-treatment process for the vinasse. During the coagulation process, colloidal and finely divided suspended matters are facilitated in the aggregation to generate larger flocs that can subsequently be separated through sedimentation or filtration to clarify water from impurities (Abujazar et al. 2022 ). The coagulation-flocculation process using poly-γ-glutamic acid combined with sodium hypochlorite and sand filtration could reduce 70% and 79.5% of the turbidity and COD concentration, respectively, in the tequila vinasse treatment (Carvajal-Zarrabal et al. 2012 ). Besides, FeCl 3 -involved coagulation post-treatment for biologically treated distillery wastewater could achieve high decolorization efficiency (Zhang et al. 2017a ). It was discovered that the ferric coagulant preferentially interacts with the aromatic compounds and melanoidins through surface complexation, charge neutralization, or both. Additionally, to reduce the coagulant dosage and increase the degradation potential, Moringa oleifera seed extract (MOSE) was used in the coagulation process with ferric sulphate and aluminium sulphate (alum) (David et al. 2016). Due to its low cost, availability, and simplicity of handling, alum has been widely used in water and wastewater (Hussaini Jagaba 2018). This study selected alum, ferric sulphate, and copper sulphate for the coagulation process to determine the COD reduction and decolorization efficiency of vinasse treatment. Biological methods are applied to utilize pollutants for microorganisms’ growth and convert the organic compounds into simpler substances through anaerobic and aerobic processes (Fito et al. 2019). Trickling filters, lagoons, and activated sludge are the most common practical conventional biological treatment methods used in industrial wastewater treatment. A biofilm-based technique called sequencing batch biofilm reactor/submerged bed biofilm reactor (SBBR) could efficiently eliminate pollutants from wastewater. (Ismail et al. 2018 ). A submerged fixed plastic carrier serves as the foundation of the SBBR system and supports associated growing aerobic bacteria (El-Shafai and Zahid 2013). The aerobic bacteria are active at eliminating organic carbon and nitrogen. SBBR is a basic system that quickly promotes the microorganism’s growth. As a result, SBBRs could remove pollutants, enhance biomass content, and prevent sludge generation while taking up minimal area, being cost-effective, simple to operate and maintain, and decreasing smell and noise (Gómez-Villalba et al. 2006 ). Sometimes, a single method is not sufficient for complete distillery wastewater treatment. When the distillery wastewater is partially treated due to the bio-recalcitrant compounds, the dark-brown effluent leaves a foul-smelling with a high COD concentration. Researchers are thus paying close attention to investigate the combined processes of physico-chemical and biological treatments (Oller et al. 2011 ). The combination of physico-chemical and biological methods included the combination of chemical coagulation, biodegradation, and photo-Fenton oxidation (Rodrigues et al. 2017 ), the combined biological-electrochemical oxidation treatment (Vilar et al. 2018 ), and the aerobic fungal growth followed by ozonation (Reis et al. 2019 ). The combined treatment showed their capability to simultaneously degrade/reduce the pollutants in terms of COD and colour concentrations. The management of distillery effluent using physico-chemical and biological methods together is sustainable and beneficial to the environment by adding value-added products (Ratna et al. 2021). The focus of the study is to compare the efficiency of three different treatment strategies: coagulation process, SBBR, and combined process of coagulation process and SBBR to produce effluent that complies with discharge standards and allows for water recycling. First, the coagulation process was carried out to examine the effects of various coagulants, initial pH, coagulant dosages, and initial COD concentration in the treatment of vinasse. Next, the effect of the substrate loading concentration was evaluated using SBBR in COD reduction and decolorization. The effect of the substrate loading concentration on the SBBR treatment performance was further analyzed using the kinetic models, ultraviolet-visible spectrophotometry (UV–Vis), and analysis of variance (ANOVA). Then, the effluents of the coagulation process and SBBR were subjected to the following treatment process as the combined sequential treatment process to determine the effectiveness of the combined technologies. 2 Materials And Methods 2.1 Sampling of wastewater The wastewater sampling was carried out at the final pond of the sugarcane ethanol industry, Fermpro Sdn. Bhd, Perlis, Malaysia. The sample was kept in the fridge at 4 ± 1°C to lower the biodegradation of the vinasse. The vinasse is alkaline (pH 8.6 ± 0.1), with the COD concentration and colour concentration of 8280 ± 180 mg/L and 46900 ± 600 Pt/C o , respectively. 2.2 Chemicals and materials The coagulants used are from HmbG Chemicals, which are alum (Al 2 (SO 4 ) 3 ), ferric sulphate (Fe 2 (SO 4 ) 3 ), and copper sulphate (CuSO 4 ). The D-Glucose anhydrous with the molecular formula of C 6 H 12 O 6 was added as an additional carbon source in the submerged bed biofilm reactor is analytical grade (Fisher Scientific). For the pH adjustment of vinasse, sodium hydroxide (NaOH) and sulphuric acid (H 2 SO 4 ) from Merck and Fisher Scientific, respectively, were chosen in this study. All chemicals were employed without further purification. 2.3 Experimental procedures 2.3.1 Chemical Coagulation As shown in Fig. 1 (a), the coagulation operations were conducted at room temperature (25 ± 3°C) in a Velp Scientifica Jar Test equipment (model JLT6). Each beaker was filled with 250 mL of vinasse, and the pH was adjusted to desired pH (pH 3, 6, 9, 12) using dilute H 2 SO 4 or NaOH solution with the concentration of 0.1–1.0 M. After adding the coagulant, the mixture was stirred rapidly (200 rpm) for 2 minutes and then stirred slowly (100 rpm) for 15 minutes, as illustrated in the literature (Lau et al. 2014 ). After the coagulation process, the effluent was settled for 1 hour. The supernatant was collected and filtered through Whatman No. 4 filter papers (12.5 cm diameter; 20–25 µm pore size). The filtrates were collected to analyze COD (mg/L) and colour concentration (PtCo). In this study, the effects of various operational parameters such as types of coagulant, initial pH, catalyst dosage, and initial COD concentration on the COD reduction and decolorization efficiency were determined. 2.3.2 Sequencing batch biofilm reactor (SBBR) The SBBR has the dimension of 30 x 20 x 20 cm 3 with 12 L of total capacity and 4 L of working volume, as shown in Fig. 1 (b). After being inoculated with activated sludge for 30 days, the microorganisms grew and attached to the bio ball, activated carbon, and bio ring. Air was delivered at a 200 mL/min rate using Atman air pump (HP-4000, China) to maintain aerobic conditions in the SBBR system. The supernatant was collected daily and analyzed for COD and colour concentrations. During the experiment, 50% of the effluent in the SBBR was evacuated after each seven-day cycle. The reactor was then fed 2.0 L of vinasse with a 0.5 g/L glucose supplement. The reactor was run at room temperature (25 ± 2°C), and the timers (Eurosafe ES-24HT) were used to control the system. The effect of substrate loading concentration on COD reduction and decolorization efficiency was investigated in this study, with substrate loading concentrations ranging from 1.0 to 5.0 g/L. The effect of the substrate loading concentration was further investigated through zero-order, first-order, and second-order kinetic studies. 2.3.3 Combined process The following combined coagulation and SBBR processes were designed and used in the experiments: (Approach 1) Coagulation process followed by SBBR (CP–SBBR) as a combined sequential treatment. First, the sugarcane vinasse was treated by coagulation under optimum conditions. Then, the wastewater that had been treated by coagulation settled for an hour, and the supernatant was filtered. Before going to SBBR, the pH of the supernatant was adjusted to 8.6, which was its original pH. The treatment processes are illustrated in Fig. 1 (a) and Fig. 1 (b). (Approach 2) SBBR followed by coagulation process (SBBR–CP) as a combined sequential treatment. The sugarcane vinasse was subjected to SBBR at the optimum substrate loading concentration, and then the supernatant was collected. The pH of the collected supernatant was optimized before continuing with the coagulation process. The treatment process is depicted in Fig. 1 (b), followed by Fig. 1 (a). 2.4 Analytical methods The vinasse treatment performances along the coagulation process, SBBR, and combined process were evaluated by collecting the influent and effluent samples. The samples collected were analyzed for COD and colour reduction. Each sample was centrifuged at 4200 rpm for 10 minutes in a benchtop centrifuge (CENCE L500) before being subjected to colour and COD analysis. Using a spectrophotometer (HACH, DR2800, USA), the COD (mg/L) was obtained using the Dichromate Reactor Digestion Method of Wastewater Analysis. Hach DR2010 spectrophotometer was utilized to measure the colour concentration (PtCo) at 455 nm. UV-Vis Spectrophotometry (UV Professional, China) was used to examine the absorption spectra between 190 to 500 nm. Methrom 826 portable pH meter was used to measure the pH and temperature during the experiments. 2.5 Statistical analysis In the current study, all values were representative of triplicate experiments, and the data were reported as mean ± standard deviation (SD). Analysis of variance (ANOVA) was also applied to investigate the impact of substrate loading concentration on COD reduction and decolorization efficiency in SBBR. The Tukey-Kramer post-hoc test was employed to examine the significance of the specific substrate loading concentration on COD reduction and decolorization efficiency. Statistics were considered significant when p-values less than 0.05. 3 Results And Discussion The experiments were divided into three different sections. First, the COD reduction and decolorization efficiency were used as indicators to investigate the effects of pH, catalyst dosage, and initial COD concentration in the coagulation process. After that, SBBR was used to study the influence of substrate loading concentration on COD reduction and decolorization efficiency. The combined sequential treatment methods were then carried out in two steps: coagulation followed by SBBR (CP-SBBR) and SBBR followed by coagulation (SBBR–CP). Both combined processes were conducted under optimal conditions. 3.1 Chemical Coagulation 3.1.1 Effect of pH on coagulation process In the coagulation-flocculation process, pH is undeniably one of the most important aspects since pH has a significant impact on floc structure, size, and the liquid/solid separation effect. The comparison of COD reduction and decolorization efficiency in the coagulation process using different pH is demonstrated in Fig. 2 . It was obvious that the highest COD reduction and decolorization efficiency achieved by alum (68.1% and 96.1%) and Fe 2 (SO 4 ) 3 (73.7% and 96.3%) was at pH 10. On the other hand, the maximum COD reduction and decolorization efficiency of the coagulation process by CuSO 4 was at pH 8 (67.5% and 95.7%). At pH 3, the alum achieved 24.5% and 59.9% of COD reduction and decolorization efficiency, which reflected that the coagulation process by alum was not suitable to carry out in the acidic condition. The high concentration of H + existing under acidic conditions makes it more challenging to hydrolyze the carboxyl groups of organic molecules (Cao et al. 2010 ). The result was similar to the condition at pH 5 by alum. Low pH may cause NOM solubility depletion and coagulation performance reduction if the primary process relies on charge neutralization (Dayarathne et al. 2021 ). Alum was more effective at reducing colour and COD concentrations as the pH went from 5 to 10, but it became less effective after reaching pH 12. The COD reduction and decolorization efficiency of alum in coagulation process were similar to Fe 2 (SO 4 ) 3 , which increased from pH 3 to pH 10. Metal ions tend to precipitate as amorphous hydroxides as pH increases. These colloidal hydroxides can adsorb other soluble species, leading to charge neutralization and destabilization in suspended colloidal systems (Dayarathne et al. 2021 ). Based on the results, it has been revealed that pH 10.0 is optimal for the alum and Fe 2 (SO 4 ) 3 in the coagulation process. The formation of the bonding flock particles using alum and Fe 2 (SO 4 ) 3 involves the presence of alkalinity in the water, which are aluminum hydroxide [Al(OH) 3 ] and ferric hydroxide [Fe(OH) 3 ], as shown in Eq. ( 1 ) and Eq. ( 2 ) (Pal 2017 ). $${Al}_{2}{(SO}_{4}{)}_{3}+6 NaOH\to 2 Al{\left(OH\right)}_{3}+3 {Na}_{2}{SO}_{4}$$ 1 $${Fe}_{2}{(SO}_{4}{)}_{3}+6 NaOH\to 2 Fe{\left(OH\right)}_{3}+3 {Na}_{2}{SO}_{4}$$ 2 Zayas et al. ( 2007 ) obtained the highest removal percentages of COD, colour, and turbidity for anaerobically treated vinasse by FeCl 3 under slightly alkaline conditions. The COD reduction and decolorization efficiency of the coagulation process by CuSO 4 increased from pH 3 to pH 8. The result was lower when the pH decreased to pH 10 and pH 12. Salts of divalent and trivalent metals can be very acidic due to the release of protons during the formation of hydroxy complexes, which lowers the pH (Matilainen et al. 2010). The minimum COD reduction and decolorization efficiency was achieved for the pH value of 12.0 by alum, Fe 2 (SO 4 ) 3 and CuSO 4 . Under the highly alkaline condition, the surface electrical property turned negative, lowering the capability of charge neutralization (Cao et al. 2010 ). The coagulation process has been extensively studied in vinasse treatment using FeCl 3 , and this study provides an additional option for vinasse treatment in coagulation/flocculation processes. 3.1.2 Effect of coagulant dosage on coagulation process The coagulation process's performance was assessed using various coagulant dosages. Figure 3 displays vinasse's COD reduction and decolorization efficiency in the coagulation process at different coagulant dosage conditions under the optimum pH of the coagulants. The optimum coagulant dosage of alum, Fe 2 (SO 4 ) 3 and CuSO 4 is 1.0 g/L. It was reported that increasing the coagulant dosage from 5 to 15 g/L in the treatment of high strength raw vinasse can increase total organic carbon (TOC) removal (Fagier et al. 2016). The charge neutralization explains the occurrence of the optimal coagulant dose. The coagulant reacted with negatively charged colloids and neutralized their charges, promoting the destabilization of the colloids (Zhang et al. 2017b ). Fe 2 (SO 4 ) 3 achieved the highest COD reduction and decolorization efficiency among the three coagulants, which are 73.7% and 96.3%. Many studies found ferric salts better than aluminium salts at removing natural organic matter (NOM). The flock particles (Fe(OH) 3 ) or ferric hydroxides have a significantly higher density than the alum flocks. As a result, they can be quickly removed from the solution by sedimentation. When the coagulant dosage was increased to 2.0 g/L, however, the COD reduction and decolorization efficiency decreased to 58.0% and 70.8%, respectively. The excessive coagulants can lead to the re-stabilization of the suspended particles, and thus the treatment efficiency was reduced (Abujazar et al. 2022 ). Underdosing promotes the formation of colloidal particles, while overdosing pollutes wastewater by increasing turbidity, organic load, and slurry volume, expanding treatment costs (Alazaiza et al. 2022 ). 3.1.3 Effect of initial COD concentration on coagulation process Practical application with the coagulation process shows that the initial COD concentration severely influences the reduction's effectiveness. Therefore, the range for the initial concentration is crucial before starting the experiments. The increase of initial COD concentration is simultaneous to the increase of colour concentration and turbidity. Figure 4 shows the effect of initial COD concentration using Fe 2 (SO 4 ) 3 since it achieved the highest COD reduction and decolorization efficiency (73.7 and 96.3%). The COD reduction and decolorization efficiency was 41.5% and 81.5% at an initial COD concentration of 500 mg/L. The highest COD reduction and decolorization efficiency were obtained at 1000 mg/L. However, the COD reduction and decolorization efficiencies decreased at 3000 mg/L (12.2% and 31.6%). The increasing initial COD concentration and turbidity could provide more available pollutant molecules and produce more collisions between the coagulant and pollutants (Wang and Chen 2020). Thus, the required coagulant dosage could be reduced at high initial COD concentration conditions (high turbidity). Furthermore, low turbidity wastewater is needed for many coagulants because of the low collision frequency between contaminants and coagulants (Bolto and Gregory 2007). Meanwhile, the coagulation process was carried out based on a 1:1 ratio of coagulant dosage (g/L) and initial COD concentration (g/L). From Fig. 5 , the COD reduction and decolorization efficiency were 79.0 ± 3.4% and 94.1 ± 1.9%. The results revealed that the coagulant dosage of Fe 2 (SO 4 ) 3 in the coagulation process was directly proportional to the initial COD concentration. According to Zhao et al. ( 2021 ), the dosages of coagulants will be added proportionally by increasing the initial concentration of the wastewater until complete charge neutralization has occurred at a given dose of coagulants. When charge neutralization is the primary mechanism, the efficiency decreases as dosage increases. Thus, optimizing dosing rates can provide additional cost savings while reducing sludge volume and treatment costs. 3.2 Sequencing batch biofilm reactor (SBBR) The SBBR was monitored for 28 operational days for the acclimatization phase, followed by 35 operational days for five batches of the cycle. SBBR was used to determine how substrate loading concentration affected COD reduction and decolorization effectiveness. The COD reduction and decolorization efficiency are demonstrated in Fig. 6 (a) and Fig. 6 (b). The COD reduction and decolorization efficiency achieved up to 80.4 ± 4.0% and 92.2 ± 3.7% after 7 days of reaction time under 1.0 g/L of substrate loading concentration. The COD reduction and decolorization efficiency increased to 84.0 ± 4.2% and 94.8 ± 3.8%, respectively, when the substrate loading concentration was changed to 2.0 g/L. When operating at a substrate loading concentration of 3.0 g/L, the SBBR could lower COD to 86.6 ± 4.3% and effectively decolorize the wastewater up to 94.6 ± 3.8%. However, only 75.8 ± 3.8% and 84.0 ± 3.4% of the COD reduction and decolorization efficiency could be obtained using 4.0 g/L of substrate loading concentration, respectively. The longer duration needed for complete degradation of the substrate may be attributed to the high COD concentration produced as a result of an increase in the organic substrate loading concentration (Yap et al. 2022 ). Furthermore, the COD reduction and decolorization efficiency were 66.8 ± 3.3% and 74.2 ± 3.0% under 5.0 g/L of substrate loading concentration. The high substrate loading concentration resulted in excess substrates and a saturated state, which inhibited microbes. Due to the high amount of substrate, microbes could not completely break down, and the COD reduction and decolorization were less effective. Zero-order, first-order, and second-order kinetic models were used to determine the COD reduction and decolorization efficiency in treating vinasse. Eq. 3, Eq. (4), and Eq. (5) show the kinetic models (Sponza and Işik 2004). \({\text{S}}_{t}={S}_{0}-{k}_{0}t\) (3) \(-ln\left(\frac{{\text{S}}_{t}}{{S}_{0}}\right)={k}_{1}t\) (4) \(\frac{1}{{S}_{t}}=\frac{1}{{S}_{0}}+{k}_{2}t\) (5) Where S t is the COD concentration at time t (mg/L), S 0 is the initial COD concentration (mg/L), t is the operational day, k 0 , k 1 , and k 2 are the zero (mg//L∙day), first (day − 1 ) and second kinetic rate constant (L/mg∙day), respectively. Tables 1 and Table 2 demonstrate regression coefficients (R 2 ) and reaction rate constants (k) for zero-order, first-order, and second-order kinetic models in the COD reduction and decolorization efficiency. The best fit was with the first-order kinetic model, which had the highest R 2 value. A similar result was obtained from (Kee et al. 2022b) in the recirculated sequencing batch reactor that the pseudo-first-order kinetic model was the best fit for the COD reduction. The highest COD reduction rate constant (k 1 COD ) was 0.1411 day -1 under a substrate loading concentration of 3.0 g/L. The k 1 COD was 1.79 times higher than when it was 1.0 g/L (0.0786 day -1 ) and 2.66 times higher than 5.0 g/L (0.0531 day -1 ). The variation in k 1 COD associated with various substrate concentrations was attributed to the influence of microbial activity on the reactor performance. Besides, the highest decolorization rate constant (k 1 Colour ) was 0.28471 day -1 under substrate loading concentration of 2.0 g/L, which was 1.02 and 4.64 times higher than that of 1.0 g/L (0.2791 day -1 ) and 5.0 g/L (0.0614 day -1 ), respectively. The result revealed that the decolorization rate was similar under low substrate loading concentrations (1.0 g/L and 2.0 g/L) and starting decreased when added the substrate loading concentration to the SBBR (> 2.0 g/L). ANOVA provided statistical evidence that demonstrated the effect of substrate loading concentration on the COD reduction and decolorization efficiency. The ANOVA results showed a significant difference between the five stages of substrate loading concentration (p < 0.05). In contrast, the Tukey post hoc test revealed no statistically significant difference in COD reduction efficiency between the 1.0 and 2.0 g/L, 1.0 and 3.0 g/L, 1.0 and 4.0 g/L, and 2.0 and 3.0 g/L groups. The results indicated that the slight increase in substrate loading concentration possessed little influence on the COD reduction efficiency (p > 0.05). The Tukey post hoc test yielded a similar result in determining the significant difference of specific substrate loading concentration in decolorization efficiency. However, the groups of 1.0 and 4.0 g/L revealed a significant difference. The result could refer to the decolorization efficiency decreased drastically from 1.0 to 4.0 g/L of substrate loading concentration 3.2.1 UV–Vis spectra analysis Figure 7 displays the impact of substrate loading concentration on UV-vis absorption spectra (190 to 500 nm) from day 1 to day 7. These results demonstrated that the absorbance bands had decreased after 7 days of reaction time. The results showed that the absorbance peak intensity at 270 nm decreased rapidly after 7 days of reaction time, representing the degradation of organic compounds (Arreola et al. 2020 ). The absorbance reduction reached 100% when considering 270 nm as the reference wavelength at the substrate loading concentration of 1.0 g/L after seven days of reaction time. However, the absorbance reduction decreased gradually to 78.2%, 62.7%, 48.5%, and 27.1% when increased the substrate loading concentration to 2.0 g/L, 3.0 g/L, 4.0 g/L, and 5.0 g/L of substrate loading concentration, respectively. Moreover, the absorbance peak intensity of 192–198 nm gradually decreased, especially in Fig. 7 (a), Fig. 7 (b), and Fig. 7 (d). The peak (λ max ) observed at 203 nm might refer to the ethanol in the vinasse (Kee et al. 2022a ). After 7 days of reaction time, the absorbance at 194 nm decreased from 1.451 to 0.626 (56.9%) when the substrate loading concentration was 1.0 g/L. The absorbance at 194 nm decreased from 1.451 to 0.626 after 7 days of reaction time under 1.0 g/L of substrate loading concentration, which achieved 56.9% of absorbance reduction. Furthermore, the absorbance reduction reduced to 40.6% and 25.3% when added substrate loading concentration to 2.0 g/L and 4.0 g/L, respectively. Under substrate loading concentrations of 3.0 g/L and 5.0 g/L, the λ max was not observed in the UV-vis spectra of 192–198 nm, as shown in Fig. 7 (c) and Fig. 7 (e). It could be related to the maximum absorbance limit (≤ 3.0) and the application of a high dilution factor. 3.3 Combined sequential process of coagulation and SBBR The results of COD reduction and decolorization efficiency, as presented in Table 3 , were related to the treatment performances of the combined process of coagulation and SBBR under optimized conditions. The SBBR-CP outperformed the CP-SBBR in terms of COD removal and decolorization efficiencies. For the approaches of SBBR-CP, the COD reduction (86.6%) and decolorization (93.0%) were achieved in the first approach of coagulation. The results improved to 97.5% of COD reduction and 99.4% decolorization after the SBBR process. It could be observed that the SBBR could remove most of the organic compounds and turbidity in the vinasse through biodegradation. The growth of microbial attachment in the biofilm can enhance the degradation of COD concentration through the aeration process (Guo et al. 2019 ). Besides, the CP-SBBR obtained high reduction efficiencies, resulting in 81.2% of COD reduction and 91.1% of decolorization. The outstanding performance of the coagulation could be related to the rapid reaction of charge neutralization between the coagulants and vinasse (Crini and Lichtfouse 2018). Further degradation by using the SBBR was achieved, and the COD reduction and decolorization reached 96.3% and 99.3%, respectively. Thus, it could be said that both combinations of the coagulation process and SBBR could maximize the reduction efficiency, where the approach of SBBR-CP achieved a slightly better result when compared to CP-SBBR. It is recommended to apply combined processes because single technology has difficulty managing vinasse due to their high organic and complex wastewater containing recalcitrant organics and persistent colour (Gebreeyessus et al. 2019). Table 1 Rate constant, k and R 2 value in zero, first and second order under various substrate loading concentration in SBBR (COD reduction) Initial COD concentration (g/L) Zero order First order Second order k 0 COD (mg//L∙day) R 2 k 1 COD (day − 1 ) R 2 k 2 COD (L/mg∙day) R 2 1.0 35.3 0.8882 0.0786 0.9224 3 x 10 − 4 0.8085 2.0 54.3 0.6464 0.0962 0.731 3 x 10 − 4 0.7924 3.0 102.5 0.9283 0.1411 0.9644 2 x 10 − 4 0.9477 4.0 169.3 0.9681 0.1115 0.9878 9 x 10 − 5 0.9505 5.00 117.2 0.9595 0.0531 0.9504 4 x 10 − 5 0.7693 Table 2 Rate constant, k and R 2 value in zero, first and second order under various initial substrate loading concentration in SBBR (decolourisation) Initial COD concentration (g/L) Zero order First order Second order k 0 Colour (mg//L∙day) R 2 k 1 Colour (day − 1 ) R 2 k 2 Colour (L/mg∙day) R 2 1.0 227 0.8465 0.2791 0.9529 4 x 10 − 4 0.9822 2.0 337 0.6878 0.2847 0.9067 3 x 10 − 4 0.9683 3.0 273 0.8408 0.1691 0.9334 1 x 10 − 4 0.986 4.0 560 0.9276 0.1303 0.9706 3 x 10 − 5 0.9661 5.0 402 0.9754 0.0614 0.985 9 x 10 − 6 0.9869 Table 3 The COD reduction and decolourisation efficiency with the combined process of coagulation and SBBR under optimized conditions SSBR-CP Parameter Initial concentration 1st approach 1st reduction (%) 2nd approach 2nd reduction (%) Overall reduction efficiency (%) COD (mg/L) 3584 482 86.6 90 81.3 97.5 Colour (Pt/Co) 13580 955 93.0 85 91.1 99.4 CP-SSBR COD (mg/L) 3000 565 81.2 110 80.5 96.3 Colour (Pt/Co) 11100 990 91.1 80 91.9 99.3 3.4 Comparison of the effectiveness of the combined processes with previous studies The past and current studies on the combined process of vinasse treatment are summarized in Table 4 . The overall COD treatment efficiency of the previous studies achieved 82.8 ± 14.4%, as shown in Table 4 . The result demonstrated that the combined process could provide excellent treatment efficiency on vinasse, similar to the current study. Notably, the combination of chemical coagulation, biodegradation, and photo-Fenton oxidation by Rodrigues et al. ( 2017 ) showed high efficiency in reducing COD (91.0%). The treated wastewater could be reused in the anaerobic reactor. Combining chemical coagulation and photo-Fenton oxidation to treat vinasses resulted in a 69.2% reduction in COD, as reported by Guerreiro et al. ( 2016 ).The coagulation process could enhance the effluent's biodegradability and eliminate its toxicity to Vibrio fischeri. In addition, Zayas et al. ( 2007 ) obtained the highest COD reduction efficiency (99.5%) through coagulation/flocculation and electrochemical processes. This finding indicated that the combined treatment could significantly reduce the biologically treated vinasse's COD, colour, and turbidity. The combined process of ultrafiltration and nanofiltration with pre-coagulation was a promising technology for treating sugarcane vinasse, according to Silva et al. (2020). Implementing the combined process could provide a 94.0% COD reduction, but the treatment cost was relatively high due to the membrane fouling. Lebron et al. ( 2020 a) used processes of coagulation, microfiltration, and nanofiltration to reduce COD concentration by 99.5%. It reported that the possibility of membrane fouling could be minimized when increasing the floc sizes with the coagulant addition and improving the back transport velocity of particles. The application of Pleurotus sajor-caju, followed by electrochemical oxidation for vinasse treatment, achieved 71% of COD reduction (Vilar et al. 2018 ). Table 4 Summary from the past studies and present study on combined process on vinasse treatment Treatments Wastewater Approach 1 Approach 2 Overall COD treatment efficiency (%) References COD reduction (%) Decolourisation / Turbidity (%) COD reduction (%) Decolourisation / Turbidity (%) Chemical coagulation, biodegradation, and photo-Fenton oxidation Sugarcane vinasse Chemical coagulation Sequencing batch reactor and photo-Fenton oxidation 91.0 (Rodrigues et al. 2017 ) 43.6 99.3 83.7 100.0 Chemical coagulation and photo-Fenton oxidation Sugarcane vinasse Photo-Fenton oxidation Chemical coagulation 69.2 (Guerreiro et al. 2016 ) 63.2 99.6 43.6 94.3 Coagulation/flocculation and electrochemical processes Biologically treated vinasse Coagulation/flocculation Electrochemical processes 99.5 (Zayas et al. 2007 ) 84.2 99.6 97.1 87.0 Process of ultrafiltration and nanofiltration with pre-coagulation Sugarcane vinasse Coagulation-ultrafiltration Nanofiltration 94.0 (Silva et al. 2020) 46.0 94.0 90.0 95.0 Coagulation-Microfiltration-Nanofiltration Sugarcane vinasse Coagulation-Microfiltration Nanofiltration 99.5 (Lebron et al. 2020 ) 71.0 68.0 98.4 99.8 Combined biological – Electrochemical oxidation treatment Sugarcane vinasse Pleurotus sajor-caju (Biodegradation) Electrochemical oxidation 80.8 (Vilar et al. 2018 ) 50.6 96.6 61.1 92.9 Combined ultrasound and heterogeneous photocatalysis Pisco vinasse Heterogeneous photocatalysis Ultrasound 70.0 (Poblete et al. 2020) 59.0 40.3 26.8 14.2 Aerobic fungal growth followed by ozonation Anaerobically digested vinasse Aerobic Fungal Growth Ozonation 59.2 (Reis et al. 2019 ) 40.8 - 31.0 - Upflow anaerobic filter-reactor and ozonation process Raw vinasse (sugar factory) Anaerobic digestion Ozonation 82.4 (Cabrera-Díaz et al. 2016 ) 82.6 9.0 29.1 93.7 Combined coagulation and submerged bed biofilm reactor Sugarcane vinasse Sequencing batch biofilm reactor Coagulation 97.5 This study 86.6 93.0 81.3 91.1 The toxicity of vinasse had been eliminated through lactuca sativa and raphidocelis subcapitata bioassays. Poblete et al. (2020) elucidated that combining ultrasound and heterogeneous photocatalysis could be a practical alternative for treating pisco vinasse because of the energy efficiency and relatively high pollutant-removal rates. Furthermore, Reis et al. ( 2019 ) reported that the aerobic fungal growth could remove over 80% of Kjeldahl-Nitrogen, followed by ozonation that depleted the phenolic compounds. Lastly, Cabrera-Díaz et al. ( 2016 ) reported that the upflow anaerobic filter-reactor achieved high COD reduction with methane production, while the ozonation process played an essential role in the complete decolorization of anaerobically digested vinasse. The 97.5% maximum COD reduction reported in the current study compared to previous studies was excellent. High COD reduction and decolorization were obtained through either coagulation or SBBR as the first approach in the treatment of sugarcane vinasse. Based on other studies, most of the combined processes still focus on combining chemical and physical processes. These phenomena could be explained by the high removal efficiency and fast reaction in the physio-chemical techniques. Typically, biological treatment requires a more prolonged start-up phase due to the slow growth of bacteria and a long hydraulic retention period (HRT). Thus, this study's combination of chemical and biological methods provided additional insight for future treatment in sugarcane vinasse. As a result, the effluent quality was enhanced, allowing for its subsequent reuse in producing bioethanol. Conclusion In the current study, coagulation and SBBR showed to be promising strategies in treating sugarcane vinasse, either in a single or combination process. First, the optimized coagulation process was obtained using Fe 2 (SO 4 ) 3 at initial pH 10, resulting in the COD reduction and decolorization efficiency of 79.0 ± 3.4% and 94.1 ± 1.9%, respectively. The optimum proportion between the initial COD concentration (g/L) and coagulant dosage (g/L) was a 1:1 ratio. Then, the maximum COD reduction (86.6 ± 4.3%) and decolorization (94.6 ± 3.8%) were achieved using SBBR at 3.0 g/L of substrate loading concentration. Furthermore, kinetic studies of SBBR were evaluated, and the first-order kinetic model was best fitted among zero, first, and second-order kinetic models. From the UV–Vis analysis, the absorbance bands at 270 nm and 192-198nm were diminished over time, which indicated the degradation of organic and alcohol compounds in SBBR. Next, two conditions of combined processes, CP–SBBR and SBBR–CP, were assessed. These two combined processes carried out at optimum operating parameters showed 97.5 and 96.3% COD reduction, with 99.4 and 99.3% decolorization for SBBR-CP and CP-SBBR, respectively. Thus, combined sequential processes of coagulation and SBBR was recommended for implementation in sugarcane vinasse treatment, where the approach of SBBR-CP achieved a slightly better result when compared to CP-SBR. Declarations Acknowledgement The authors would like to express their sincere gratitude to the Faculty of Civil Engineering Technology Universiti Malaysia Perlis (UniMAP), and Fermpro Industries. Ethics approval and consent to participate Not applicable Consent for publication Not applicable Availability of data and materials All data generated or analysed during this study are included in this published article. Competing interests The authors declare that they have no competing interests. Funding No funding was received to assist with the preparation of this manuscript. Authors’ contributions Conceptualization and methodology were prepared by Yee-Shian Wong and Wei-Chin Kee. Formal analysis and investigation were performed by Yee-Shian Wong, Wei-Chin Kee, and Audrey Chai. The first draft of the manuscript was written by Wei-Chin Kee, and all authors commented on previous versions of the manuscript. Resources and supervision were provided by Yee-Shian Wong, Soon-An Ong, Nabilah Aminah Lutpi, Sung-Ting Sam, Farrah Aini Dahalan, and Kim-Mun Eng. All authors read and approved the final manuscript. References Abujazar MSS, KaraağaçSU, Abu AmrSS et al (2022) Recent advancement in the application of hybrid coagulants in coagulation-flocculation of wastewater: A review. J Clean Prod 345. https://doi.org/10.1016/j.jclepro.2022.131133 Alazaiza MYD, AlbahnasawiA AliGAM et al (2022) Application of Natural Coagulants for Pharmaceutical Removal from Water and Wastewater: A Review. Water (Switzerland) 14:1–16. https://doi.org/10.3390/w14020140 Arreola AR, TizapaMS ZuritaF et al (2020) Treatment of tequila vinasse and elimination of phenol by coagulation–flocculation process coupled with heterogeneous photocatalysis using titanium dioxide nanoparticles. Environ Technol (United Kingdom) 41:1023–1033. https://doi.org/10.1080/09593330.2018.1518994 Bolto B, GregoryJ (2007) Organic polyelectrolytes in water treatment. Water Res 41:2301–2324. https://doi.org/10.1016/j.watres.2007.03.012 Cabrera-Díaz A, Pereda-ReyesI, Dueñas-MorenoJ et al (2016) Combined treatment of vinasse by an upflow anaerobic filter-reactor and ozonation process. Brazilian J Chem Eng 33:753–762. https://doi.org/10.1590/0104-6632.20160334s20150268 Cao BC, GaoBY, XuCH et al (2010) Effects of pH on coagulation behavior and floc properties in Yellow River water treatment using ferric based coagulants. Chin Sci Bull 55:1382–1387. https://doi.org/10.1007/s11434-010-0087-5 Carpanez TG, MoreiraVR, AssisIR AmaralMCS (2022) Sugarcane vinasse as organo-mineral fertilizers feedstock: Opportunities and environmental risks. Sci Total Environ 832:154998. https://doi.org/10.1016/j.scitotenv.2022.154998 Carvajal-Zarrabal O, Nolasco-HipólitoC Barradas-DermitzDM et al (2012) Treatment of vinasse from tequila production using polyglutamic acid. J Environ Manage 95:S66–S70. https://doi.org/10.1016/j.jenvman.2011.05.001 Chai A, WongYS, OngSA et al (2021) Haldane-Andrews substrate inhibition kinetics for pilot scale thermophilic anaerobic degradation of sugarcane vinasse. Bioresour Technol 336:125319. https://doi.org/10.1016/j.biortech.2021.125319 Crini G (2018) LichtfouseE Wastewater Treatment: An Overview. pp 1–21 David C, NarlawarR ArivazhaganM (2016) Performance Evaluation of Moringa oleifera Seed Extract (MOSE) in Conjunction with Chemical Coagulants for Treating Distillery Spent Wash. Indian Chem Eng 58:189–200. https://doi.org/10.1080/00194506.2015.1006147 Dayarathne HNP, AngoveMJ AryalR et al (2021) Removal of natural organic matter from source water: Review on coagulants, dual coagulation, alternative coagulants, and mechanisms. J Water Process Eng 40:101820. https://doi.org/10.1016/j.jwpe.2020.101820 El-Shafai SA, ZahidWM (2013) Performance of aerated submerged biofilm reactor packed with local scoria for carbon and nitrogen removal from municipal wastewater. Bioresour Technol 143:476–482. https://doi.org/10.1016/j.biortech.2013.06.027 España-Gamboa E, Mijangos-CortesJ Barahona-PerezL et al (2011) Vinasses: Characterization and treatments. Waste Manag Res 29:1235–1250. https://doi.org/10.1177/0734242X10387313 Fagier MA, AliEA, TayKS AbasMRB (2016) Mineralization of organic matter from vinasse using physicochemical treatment coupled with Fe2+-activated persulfate and peroxymonosulfate oxidation. Int J Environ Sci Technol 13:1189–1194. https://doi.org/10.1007/s13762-016-0963-x Fito J, TeferaN VanHulleSWH (2019) Sugarcane biorefineries wastewater: bioremediation technologies for environmental sustainability. Chem Biol Technol Agric 6:1–13. https://doi.org/10.1186/s40538-019-0144-5 Fuess LT, GarciaML (2014) Implications of stillage land disposal: A critical review on the impacts of fertigation. J Environ Manage 145:210–229. https://doi.org/10.1016/j.jenvman.2014.07.003 Gebreeyessus GD, MekonenA AlemayehuE (2019) A review on progresses and performances in distillery stillage management. J Clean Prod 232:295–307. https://doi.org/10.1016/j.jclepro.2019.05.383 Gómez-Villalba B, CalvoC VilchezR et al (2006) TGGE analysis of the diversity of ammonia-oxidizing and denitrifying bacteria in submerged filter biofilms for the treatment of urban wastewater. Appl Microbiol Biotechnol 72:393–400. https://doi.org/10.1007/s00253-005-0272-7 Guerreiro LF, RodriguesCSD DudaRM et al (2016) Treatment of sugarcane vinasse by combination of coagulation/flocculation and Fenton’s oxidation. J Environ Manage 181:237–248. https://doi.org/10.1016/j.jenvman.2016.06.027 Guo X, LiB ZhaoR et al (2019) Performance and bacterial community of moving bed biofilm reactors with various biocarriers treating primary wastewater effluent with a low organic strength and low C/N ratio. https://doi.org/10.1016/j.biortech.2019.121424 . Bioresour Technol 287: Hoarau J, CaroY, GrondinI PetitT (2018) Sugarcane vinasse processing: Toward a status shift from waste to valuable resource. A review. J Water Process Eng 24:11–25. https://doi.org/10.1016/j.jwpe.2018.05.003 Hussaini Jagaba A (2018) Wastewater Treatment Using Alum, the Combinations of Alum-Ferric Chloride, Alum-Chitosan, Alum-Zeolite and Alum- Moringa Oleifera as Adsorbent and Coagulant. Int J Eng Manag 2:67. https://doi.org/10.11648/j.ijem.20180203.13 Ismail Z, AzizMMA MahmoodNAN et al (2018) Optimisation of a modified submerged bed biofilm reactor for biological oleochemical wastewater treatment. J Environ Manage 226:156–162. https://doi.org/10.1016/j.jenvman.2018.08.003 Kee W-C et al (2022a) Photocatalytic Degradation of Sugarcane Vinasse Using ZnO Photocatalyst: Operating Parameters, Kinetic Studies, Phytotoxicity Assessments, and Reusability. Int J Environ Res 16. https://doi.org/10.1007/s41742-021-00382-6 Kee WC, WongYS OngSA et al (2022b) Insights into modified sequencing batch reactor for the treatment of sugarcane vinasse: role of recirculation process. Int J Environ Sci Technol. https://doi.org/10.1007/s13762-022-03946-x Kiani Deh Kiani M, ParsaeeM MahdavifarZ (2021) Biogas production from sugarcane vinasse at mesophilic and thermophilic temperatures by static granular bed reactor (SGBR). Sustain Energy Technol Assessments 48:101569. https://doi.org/10.1016/j.seta.2021.101569 Lau YY, WongYS TengTT et al (2014) Coagulation-flocculation of azo dye acid orange 7 with green refined laterite soil. Chem Eng J 246:383–390. https://doi.org/10.1016/j.cej.2014.02.100 Lebron YAR, MoreiraVR FurtadoTPB et al (2020) Vinasse treatment using hybrid tannin-based Coagulation-Microfiltration-Nanofiltration processes: Potential energy recovery, technical and economic feasibility assessment. Sep Purif Technol 248:117152. https://doi.org/10.1016/j.seppur.2020.117152 Matilainen A, VepsäläinenM SillanpääM (2010) Natural organic matter removal by coagulation during drinking water treatment: A review. Adv Colloid Interface Sci 159:189–197. https://doi.org/10.1016/j.cis.2010.06.007 Oller I, MalatoS, Sánchez-PérezJA (2011) Combination of Advanced Oxidation Processes and biological treatments for wastewater decontamination-A review. Sci Total Environ 409:4141–4166. https://doi.org/10.1016/j.scitotenv.2010.08.061 Pal P (2017) Chemical Treatment Technology Poblete R, CortesE, SalihogluG SalihogluNK (2020) Ultrasound and heterogeneous photocatalysis for the treatment of vinasse from pisco production. Ultrason Sonochem 61:104825. https://doi.org/10.1016/j.ultsonch.2019.104825 Ratna S, RastogiS KumarR (2021) Current trends for distillery wastewater management and its emerging applications for sustainable environment. J Environ Manage 290:112544. https://doi.org/10.1016/j.jenvman.2021.112544 Reis CER, BentoHBS AlvesTM et al (2019) Vinasse treatment within the sugarcane-ethanol industry using ozone combined with anaerobic and aerobic microbial processes. Environ - MDPI 6. https://doi.org/10.3390/environments6010005 Rodrigues CSD, NetoAR DudaRM et al (2017) Combination of chemical coagulation, photo-Fenton oxidation and biodegradation for the treatment of vinasse from sugar cane ethanol distillery. J Clean Prod 142:3634–3644. https://doi.org/10.1016/j.jclepro.2016.10.104 Silva AFR, BrasilYL, KochK AmaralMCS (2021) Resource recovery from sugarcane vinasse by anaerobic digestion – A review. J Environ Manage 295:113137. https://doi.org/10.1016/j.jenvman.2021.113137 Silva SCda MoraviaMCSA, CoutoCF (2020) Combined Process of Ultrafiltration and Nanofiltration for Vinasse Treatment With and Without Pre-Coagulation. J Water Process Eng 36:101326. https://doi.org/10.1016/j.jwpe.2020.101326 Sponza DT, IşikM (2004) Decolorization and inhibition kinetic of Direct Black 38 azo dye with granulated anaerobic sludge. Enzyme Microb Technol 34:147–158. https://doi.org/10.1016/j.enzmictec.2003.10.006 Takeda PY, OliveiraCA EduardaM et al (2022) Enhancing the energetic potential of sugarcane biore fi nery exchanging vinasse and glycerol in sugarcane off-season in an anaerobic reactor. 195. https://doi.org/10.1016/j.renene.2022.06.128 Vilar DS, CarvalhoGO PupoMMS et al (2018) Vinasse degradation using Pleurotus sajor-caju in a combined biological – Electrochemical oxidation treatment. Sep Purif Technol 192:287–296. https://doi.org/10.1016/j.seppur.2017.10.017 Wang J, ChenX (2020) Removal of antibiotic resistance genes (ARGs) in various wastewater treatment processes: An overview. Crit Rev Environ Sci Technol 52:571–630. https://doi.org/10.1080/10643389.2020.1835124 Yap KL, HoLN OngSA et al (2022) Microbial fuel cell for simultaneous caffeine removal and bioelectricity generation under various operational conditions in the anodic and cathodic chambers. Environ Technol Innov 25:102158. https://doi.org/10.1016/j.eti.2021.102158 Zayas T, RómeroV SalgadoL et al (2007) Applicability of coagulation/flocculation and electrochemical processes to the purification of biologically treated vinasse effluent. Sep Purif Technol 57:270–276. https://doi.org/10.1016/j.seppur.2007.04.019 Zhang M, WangZ LiP et al (2017a) Bio-refractory dissolved organic matter and colorants in cassava distillery wastewater: Characterization, coagulation treatment and mechanisms. Chemosphere 178:259–267. https://doi.org/10.1016/j.chemosphere.2017.03.065 Zhang W, GaoH, HeJ et al (2017b) Removal of norfloxacin using coupled synthesized nanoscale zero-valent iron (nZVI) with H2O2 system: Optimization of operating conditions and degradation pathway. Sep Purif Technol 172:158–167. https://doi.org/10.1016/j.seppur.2016.08.008 Zhao C, ZhouJ YanY et al (2021) Application of coagulation/flocculation in oily wastewater treatment: A review. Sci Total Environ 765:142795. https://doi.org/10.1016/j.scitotenv.2020.142795 Supplementary Files Graphicalabstract.pdf Cite Share Download PDF Status: Published Journal Publication published 21 Apr, 2023 Read the published version in Environmental Science and Pollution Research → Version 1 posted Editorial decision: Major Revision 06 Dec, 2022 Reviewers invited by journal 24 Oct, 2022 Reviewers agreed at journal 15 Oct, 2022 Editor invited by journal 15 Sep, 2022 Editor assigned by journal 05 Sep, 2022 First submitted to journal 31 Aug, 2022 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-2007267","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":144434052,"identity":"38ba0aa7-f1af-4ef8-b213-81ebb7ab1e46","order_by":0,"name":"Wei-Chin Kee","email":"","orcid":"","institution":"Universiti Malaysia Perlis","correspondingAuthor":false,"prefix":"","firstName":"Wei-Chin","middleName":"","lastName":"Kee","suffix":""},{"id":144434053,"identity":"e020998e-5404-4ee2-a87a-bc9abfa0ddb9","order_by":1,"name":"Yee-Shian Wong","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA3ElEQVRIiWNgGAWjYPACGwYGZgiLsYFILWmkazkMZxHWYnD+jOHjgl/nE7ezcyd+LmCwkd1wgDtNAq+WGznGxjP7bifubObdLD2DIc14wwHebQS08G6T5u25nbjhMO8GaR6Gw4mEtZw/C9JyDqRl828ehv9EaDmQu02a58cBkBYgg+EAYS2SN/I/G/M2JBuDtFjPMEg2ngm0zgKfFr7zxxIf8/yxk91w/uzm2wUVdrJ9x3s33sCnReEAkGBsg3CYGQzAJAteh8k3gMg/MC1Q+gM+LaNgFIyCUTDiAAANnVDmttFHtwAAAABJRU5ErkJggg==","orcid":"https://orcid.org/0000-0002-6238-5247","institution":"Universiti Malaysia Perlis","correspondingAuthor":true,"prefix":"","firstName":"Yee-Shian","middleName":"","lastName":"Wong","suffix":""},{"id":144434054,"identity":"e7fa8319-7e0e-41b9-a0f4-8fed659588d7","order_by":2,"name":"Soon-An Ong","email":"","orcid":"","institution":"Universiti Malaysia Perlis","correspondingAuthor":false,"prefix":"","firstName":"Soon-An","middleName":"","lastName":"Ong","suffix":""},{"id":144434055,"identity":"2a84b6a5-0e00-4a9f-bbd0-255afd2eef00","order_by":3,"name":"Nabilah Aminah Lutpi","email":"","orcid":"","institution":"Universiti Malaysia Perlis","correspondingAuthor":false,"prefix":"","firstName":"Nabilah","middleName":"Aminah","lastName":"Lutpi","suffix":""},{"id":144434056,"identity":"2bf516ef-42ad-4b79-820c-7dc455a2bd41","order_by":4,"name":"Sung-Ting Sam","email":"","orcid":"","institution":"Universiti Malaysia Perlis","correspondingAuthor":false,"prefix":"","firstName":"Sung-Ting","middleName":"","lastName":"Sam","suffix":""},{"id":144434057,"identity":"f5acd89c-6d3a-4195-89fb-0a443c06297c","order_by":5,"name":"Farrah Aini Dahalan","email":"","orcid":"","institution":"Universiti Malaysia Perlis","correspondingAuthor":false,"prefix":"","firstName":"Farrah","middleName":"Aini","lastName":"Dahalan","suffix":""},{"id":144434058,"identity":"c0aee5c9-c158-470b-94a5-44a65fe81291","order_by":6,"name":"Audrey Chai","email":"","orcid":"","institution":"Universiti Malaysia Perlis","correspondingAuthor":false,"prefix":"","firstName":"Audrey","middleName":"","lastName":"Chai","suffix":""},{"id":144434059,"identity":"01ebb008-9704-4dff-8c9a-3d4ee52653dc","order_by":7,"name":"Kim-Mun Eng","email":"","orcid":"","institution":"Kenep Resources (Asia) Sdn. Bhd","correspondingAuthor":false,"prefix":"","firstName":"Kim-Mun","middleName":"","lastName":"Eng","suffix":""}],"badges":[],"createdAt":"2022-08-28 16:30:21","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-2007267/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-2007267/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s11356-023-27046-6","type":"published","date":"2023-04-21T20:30:40+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":27954363,"identity":"ed7c771e-8058-4d3c-b7f4-f2558803880a","added_by":"auto","created_at":"2022-10-18 18:49:57","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":657508,"visible":true,"origin":"","legend":"\u003cp\u003eThe schematic diagram of (a) coagulation and (b) sequencing batch biofilm reactor (SBBR).\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-2007267/v1/fdd8e2352d5a9c4cb512a7e7.jpeg"},{"id":27954126,"identity":"8aef7d7a-f74d-48ac-854a-7b6ffe58f07a","added_by":"auto","created_at":"2022-10-18 18:44:57","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":60476,"visible":true,"origin":"","legend":"\u003cp\u003eThe study of coagulation process under effect of initial pH in terms of COD reduction and decolourization efficiency using various types of coagulants [1.0 g/L coagulant dosage; 1.0 g/L initial COD concentration].\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-2007267/v1/7a67ac987ec4bb2306e7d3c9.png"},{"id":27954365,"identity":"69ba7cfe-6125-47c7-9b19-321d7f4011b3","added_by":"auto","created_at":"2022-10-18 18:49:57","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":55763,"visible":true,"origin":"","legend":"\u003cp\u003eThe study of coagulation process under effect of coagulant dosage in terms of COD reduction and decolourization efficiency using various types of coagulants [optimum pH for each coagulant; 1.0 g/L initial COD concentration].\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-2007267/v1/85296d6720a6db64d91dcc13.png"},{"id":27954362,"identity":"20667707-54d5-4d74-832e-a23aa53cb47e","added_by":"auto","created_at":"2022-10-18 18:49:57","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":20701,"visible":true,"origin":"","legend":"\u003cp\u003eThe study of coagulation process under effect of initial COD concentration in terms of COD reduction and decolourization efficiency using Fe\u003csub\u003e2\u003c/sub\u003e(SO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e [initial pH 10; 1.0 g/L coagulant dosage].\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-2007267/v1/cb368af17eaf02c817b9b259.png"},{"id":27954463,"identity":"8c42132e-0ba2-4c97-83bb-1ff9a1271edc","added_by":"auto","created_at":"2022-10-18 18:54:57","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":19047,"visible":true,"origin":"","legend":"\u003cp\u003eThe study of relationship between the effects of coagulant dosage and initial COD concentration in terms of COD reduction and decolourization efficiency using Fe\u003csub\u003e2\u003c/sub\u003e(SO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e during coagulation process [initial pH 10]\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-2007267/v1/082f8634e0d408c1aa672ebc.png"},{"id":27954131,"identity":"9cbf42a9-5304-4022-a7c8-18f1cde13f1a","added_by":"auto","created_at":"2022-10-18 18:44:57","extension":"jpeg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":447356,"visible":true,"origin":"","legend":"\u003cp\u003eReduction efficiency of sugarcane vinasse using SBBR under the effect of substrate loading concentration in terms of (a) COD, and (b) colour.\u003c/p\u003e","description":"","filename":"floatimage6.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-2007267/v1/37bcd6e4a9b9c50efe811373.jpeg"},{"id":27954130,"identity":"b86e65d8-15de-4299-ab21-5b55da0228d2","added_by":"auto","created_at":"2022-10-18 18:44:57","extension":"jpg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":60176,"visible":true,"origin":"","legend":"\u003cp\u003eUV–vis spectrum analysis for the treatment of sugarcane vinasse using SBBR under the effect of substrate loading concentration [(a) 1.0 g/L; (b) 2.0 g/L; (c) 3.0 g/L; (d) 4.0 g/L; (e) 5.0 g/L]\u003c/p\u003e","description":"","filename":"Fig7.jpg","url":"https://assets-eu.researchsquare.com/files/rs-2007267/v1/032c93ed94761b9e055f6df5.jpg"},{"id":44725361,"identity":"062a9252-1a1d-4c5f-943a-aad43193a8cd","added_by":"auto","created_at":"2023-10-16 20:40:38","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":880608,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-2007267/v1/2bf91e5b-5f03-4b87-8029-28005f2f077f.pdf"},{"id":27954133,"identity":"e8a03968-1a90-47eb-adc6-40ac7075440d","added_by":"auto","created_at":"2022-10-18 18:44:57","extension":"pdf","order_by":7,"title":"","display":"","copyAsset":false,"role":"supplement","size":171533,"visible":true,"origin":"","legend":"","description":"","filename":"Graphicalabstract.pdf","url":"https://assets-eu.researchsquare.com/files/rs-2007267/v1/4b7b05d734f78f57ca584a3b.pdf"}],"financialInterests":"","formattedTitle":"Chemical and biological combined treatment for the sugarcane vinasse: Selection of parameters and performance studies","fulltext":[{"header":"1 Introduction","content":"\u003cp\u003eSugarcane vinasse is one of the most generated wastewaters in the bioethanol distillery, and one liter of bioethanol production could generate around nine to fourteen liters of sugarcane vinasse (Espa\u0026ntilde;a-Gamboa et al. \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). Vinasse contains a lot of harmful substances, such as phenols, polyphenols, and heavy metals, as well as significant levels of organic content and dissolved solids. Its characteristics of being acidic (pH of 4.30\u0026ndash;4.55), dark brown, and having a high chemical oxygen demand (COD) concentration (28.5\u0026ndash;85.0 gCOD/L) are necessary to be a concern since the phytotoxic and recalcitrant compounds in the sugarcane vinasse could negatively affect the organisms at disposal sites (Chai et al. \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; Kiani Deh Kiani et al. 2021; Takeda et al. \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Disposing of untreated/partially treated vinasse on land or groundwater could cause a profound environmental impact. Thus, the bioethanol industry has adopted some technological applications such as fertigation (Carpanez et al. 2022), physico-chemical (Hoarau et al. 2018), and biological treatments (Silva et al. 2021). Fertigation using sugarcane vinasse is commonly applied due to the increase of crop productivity without complex technologies for its management; however, its uncontrolled practice can cause soil salinization, water sources contamination, and bad odors release (Fuess and Garcia 2014).\u003c/p\u003e \u003cp\u003eThe coagulation/flocculation method is the most common chemical treatment technology, especially as a pre-treatment process for the vinasse. During the coagulation process, colloidal and finely divided suspended matters are facilitated in the aggregation to generate larger flocs that can subsequently be separated through sedimentation or filtration to clarify water from impurities (Abujazar et al. \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). The coagulation-flocculation process using poly-γ-glutamic acid combined with sodium hypochlorite and sand filtration could reduce 70% and 79.5% of the turbidity and COD concentration, respectively, in the tequila vinasse treatment (Carvajal-Zarrabal et al. \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). Besides, FeCl\u003csub\u003e3\u003c/sub\u003e-involved coagulation post-treatment for biologically treated distillery wastewater could achieve high decolorization efficiency (Zhang et al. \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e2017a\u003c/span\u003e). It was discovered that the ferric coagulant preferentially interacts with the aromatic compounds and melanoidins through surface complexation, charge neutralization, or both. Additionally, to reduce the coagulant dosage and increase the degradation potential, Moringa oleifera seed extract (MOSE) was used in the coagulation process with ferric sulphate and aluminium sulphate (alum) (David et al. 2016). Due to its low cost, availability, and simplicity of handling, alum has been widely used in water and wastewater (Hussaini Jagaba 2018). This study selected alum, ferric sulphate, and copper sulphate for the coagulation process to determine the COD reduction and decolorization efficiency of vinasse treatment.\u003c/p\u003e \u003cp\u003eBiological methods are applied to utilize pollutants for microorganisms\u0026rsquo; growth and convert the organic compounds into simpler substances through anaerobic and aerobic processes (Fito et al. 2019). Trickling filters, lagoons, and activated sludge are the most common practical conventional biological treatment methods used in industrial wastewater treatment. A biofilm-based technique called sequencing batch biofilm reactor/submerged bed biofilm reactor (SBBR) could efficiently eliminate pollutants from wastewater. (Ismail et al. \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). A submerged fixed plastic carrier serves as the foundation of the SBBR system and supports associated growing aerobic bacteria (El-Shafai and Zahid 2013). The aerobic bacteria are active at eliminating organic carbon and nitrogen. SBBR is a basic system that quickly promotes the microorganism\u0026rsquo;s growth. As a result, SBBRs could remove pollutants, enhance biomass content, and prevent sludge generation while taking up minimal area, being cost-effective, simple to operate and maintain, and decreasing smell and noise (G\u0026oacute;mez-Villalba et al. \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2006\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eSometimes, a single method is not sufficient for complete distillery wastewater treatment. When the distillery wastewater is partially treated due to the bio-recalcitrant compounds, the dark-brown effluent leaves a foul-smelling with a high COD concentration. Researchers are thus paying close attention to investigate the combined processes of physico-chemical and biological treatments (Oller et al. \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). The combination of physico-chemical and biological methods included the combination of chemical coagulation, biodegradation, and photo-Fenton oxidation (Rodrigues et al. \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2017\u003c/span\u003e), the combined biological-electrochemical oxidation treatment (Vilar et al. \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e2018\u003c/span\u003e), and the aerobic fungal growth followed by ozonation (Reis et al. \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). The combined treatment showed their capability to simultaneously degrade/reduce the pollutants in terms of COD and colour concentrations. The management of distillery effluent using physico-chemical and biological methods together is sustainable and beneficial to the environment by adding value-added products (Ratna et al. 2021).\u003c/p\u003e \u003cp\u003eThe focus of the study is to compare the efficiency of three different treatment strategies: coagulation process, SBBR, and combined process of coagulation process and SBBR to produce effluent that complies with discharge standards and allows for water recycling. First, the coagulation process was carried out to examine the effects of various coagulants, initial pH, coagulant dosages, and initial COD concentration in the treatment of vinasse. Next, the effect of the substrate loading concentration was evaluated using SBBR in COD reduction and decolorization. The effect of the substrate loading concentration on the SBBR treatment performance was further analyzed using the kinetic models, ultraviolet-visible spectrophotometry (UV\u0026ndash;Vis), and analysis of variance (ANOVA). Then, the effluents of the coagulation process and SBBR were subjected to the following treatment process as the combined sequential treatment process to determine the effectiveness of the combined technologies.\u003c/p\u003e"},{"header":"2 Materials And Methods","content":"\u003cdiv class=\"Section2\" id=\"Sec3\"\u003e\n \u003ch2\u003e2.1 Sampling of wastewater\u003c/h2\u003e\n \u003cp\u003eThe wastewater sampling was carried out at the final pond of the sugarcane ethanol industry, Fermpro Sdn. Bhd, Perlis, Malaysia. The sample was kept in the fridge at 4\u0026thinsp;\u0026plusmn;\u0026thinsp;1\u0026deg;C to lower the biodegradation of the vinasse. The vinasse is alkaline (pH 8.6\u0026thinsp;\u0026plusmn;\u0026thinsp;0.1), with the COD concentration and colour concentration of 8280\u0026thinsp;\u0026plusmn;\u0026thinsp;180 mg/L and 46900\u0026thinsp;\u0026plusmn;\u0026thinsp;600 Pt/C\u003csub\u003eo\u003c/sub\u003e, respectively.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec4\"\u003e\n \u003ch2\u003e2.2 Chemicals and materials\u003c/h2\u003e\n \u003cp\u003eThe coagulants used are from HmbG Chemicals, which are alum (Al\u003csub\u003e2\u003c/sub\u003e(SO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e), ferric sulphate (Fe\u003csub\u003e2\u003c/sub\u003e(SO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e), and copper sulphate (CuSO\u003csub\u003e4\u003c/sub\u003e). The D-Glucose anhydrous with the molecular formula of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e12\u003c/sub\u003eO\u003csub\u003e6\u003c/sub\u003e was added as an additional carbon source in the submerged bed biofilm reactor is analytical grade (Fisher Scientific). For the pH adjustment of vinasse, sodium hydroxide (NaOH) and sulphuric acid (H\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e) from Merck and Fisher Scientific, respectively, were chosen in this study. All chemicals were employed without further purification.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec5\"\u003e\n \u003ch2\u003e2.3 Experimental procedures\u003c/h2\u003e\n \u003cdiv class=\"Section3\" id=\"Sec6\"\u003e\n \u003ch2\u003e2.3.1 Chemical Coagulation\u003c/h2\u003e\n \u003cp\u003eAs shown in Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e(a), the coagulation operations were conducted at room temperature (25\u0026thinsp;\u0026plusmn;\u0026thinsp;3\u0026deg;C) in a Velp Scientifica Jar Test equipment (model JLT6). Each beaker was filled with 250 mL of vinasse, and the pH was adjusted to desired pH (pH 3, 6, 9, 12) using dilute H\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e or NaOH solution with the concentration of 0.1\u0026ndash;1.0 M. After adding the coagulant, the mixture was stirred rapidly (200 rpm) for 2 minutes and then stirred slowly (100 rpm) for 15 minutes, as illustrated in the literature (Lau et al. \u003cspan class=\"CitationRef\"\u003e2014\u003c/span\u003e). After the coagulation process, the effluent was settled for 1 hour. The supernatant was collected and filtered through Whatman No. 4 filter papers (12.5 cm diameter; 20\u0026ndash;25 \u0026micro;m pore size). The filtrates were collected to analyze COD (mg/L) and colour concentration (PtCo). In this study, the effects of various operational parameters such as types of coagulant, initial pH, catalyst dosage, and initial COD concentration on the COD reduction and decolorization efficiency were determined.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv class=\"Section3\" id=\"Sec7\"\u003e\n \u003ch2\u003e2.3.2 Sequencing batch biofilm reactor (SBBR)\u003c/h2\u003e\n \u003cp\u003eThe SBBR has the dimension of 30 x 20 x 20 cm\u003csup\u003e3\u003c/sup\u003e with 12 L of total capacity and 4 L of working volume, as shown in Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e(b). After being inoculated with activated sludge for 30 days, the microorganisms grew and attached to the bio ball, activated carbon, and bio ring. Air was delivered at a 200 mL/min rate using Atman air pump (HP-4000, China) to maintain aerobic conditions in the SBBR system. The supernatant was collected daily and analyzed for COD and colour concentrations. During the experiment, 50% of the effluent in the SBBR was evacuated after each seven-day cycle. The reactor was then fed 2.0 L of vinasse with a 0.5 g/L glucose supplement. The reactor was run at room temperature (25\u0026thinsp;\u0026plusmn;\u0026thinsp;2\u0026deg;C), and the timers (Eurosafe ES-24HT) were used to control the system. The effect of substrate loading concentration on COD reduction and decolorization efficiency was investigated in this study, with substrate loading concentrations ranging from 1.0 to 5.0 g/L. The effect of the substrate loading concentration was further investigated through zero-order, first-order, and second-order kinetic studies.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv class=\"Section3\" id=\"Sec8\"\u003e\n \u003ch2\u003e2.3.3 Combined process\u003c/h2\u003e\n \u003cp\u003eThe following combined coagulation and SBBR processes were designed and used in the experiments:\u003c/p\u003e\n \u003cp\u003e(Approach 1) Coagulation process followed by SBBR (CP\u0026ndash;SBBR) as a combined sequential treatment. First, the sugarcane vinasse was treated by coagulation under optimum conditions. Then, the wastewater that had been treated by coagulation settled for an hour, and the supernatant was filtered. Before going to SBBR, the pH of the supernatant was adjusted to 8.6, which was its original pH. The treatment processes are illustrated in Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e(a) and Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e(b).\u003c/p\u003e\n \u003cp\u003e(Approach 2) SBBR followed by coagulation process (SBBR\u0026ndash;CP) as a combined sequential treatment. The sugarcane vinasse was subjected to SBBR at the optimum substrate loading concentration, and then the supernatant was collected. The pH of the collected supernatant was optimized before continuing with the coagulation process. The treatment process is depicted in Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e(b), followed by Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e(a).\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec9\"\u003e\n \u003ch2\u003e2.4 Analytical methods\u003c/h2\u003e\n \u003cp\u003eThe vinasse treatment performances along the coagulation process, SBBR, and combined process were evaluated by collecting the influent and effluent samples. The samples collected were analyzed for COD and colour reduction. Each sample was centrifuged at 4200 rpm for 10 minutes in a benchtop centrifuge (CENCE L500) before being subjected to colour and COD analysis. Using a spectrophotometer (HACH, DR2800, USA), the COD (mg/L) was obtained using the Dichromate Reactor Digestion Method of Wastewater Analysis. Hach DR2010 spectrophotometer was utilized to measure the colour concentration (PtCo) at 455 nm. UV-Vis Spectrophotometry (UV Professional, China) was used to examine the absorption spectra between 190 to 500 nm. Methrom 826 portable pH meter was used to measure the pH and temperature during the experiments.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec10\"\u003e\n \u003ch2\u003e2.5 Statistical analysis\u003c/h2\u003e\n \u003cp\u003eIn the current study, all values were representative of triplicate experiments, and the data were reported as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (SD). Analysis of variance (ANOVA) was also applied to investigate the impact of substrate loading concentration on COD reduction and decolorization efficiency in SBBR. The Tukey-Kramer post-hoc test was employed to examine the significance of the specific substrate loading concentration on COD reduction and decolorization efficiency. Statistics were considered significant when p-values less than 0.05.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"3 Results And Discussion","content":"\u003cp\u003eThe experiments were divided into three different sections. First, the COD reduction and decolorization efficiency were used as indicators to investigate the effects of pH, catalyst dosage, and initial COD concentration in the coagulation process. After that, SBBR was used to study the influence of substrate loading concentration on COD reduction and decolorization efficiency. The combined sequential treatment methods were then carried out in two steps: coagulation followed by SBBR (CP-SBBR) and SBBR followed by coagulation (SBBR\u0026ndash;CP). Both combined processes were conducted under optimal conditions.\u003c/p\u003e\n\u003cdiv class=\"Section2\" id=\"Sec12\"\u003e\n \u003ch2\u003e3.1 Chemical Coagulation\u003c/h2\u003e\n \u003cdiv class=\"Section3\" id=\"Sec13\"\u003e\n \u003ch2\u003e3.1.1 Effect of pH on coagulation process\u003c/h2\u003e\n \u003cp\u003eIn the coagulation-flocculation process, pH is undeniably one of the most important aspects since pH has a significant impact on floc structure, size, and the liquid/solid separation effect. The comparison of COD reduction and decolorization efficiency in the coagulation process using different pH is demonstrated in Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e. It was obvious that the highest COD reduction and decolorization efficiency achieved by alum (68.1% and 96.1%) and Fe\u003csub\u003e2\u003c/sub\u003e(SO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e (73.7% and 96.3%) was at pH 10. On the other hand, the maximum COD reduction and decolorization efficiency of the coagulation process by CuSO\u003csub\u003e4\u003c/sub\u003e was at pH 8 (67.5% and 95.7%). At pH 3, the alum achieved 24.5% and 59.9% of COD reduction and decolorization efficiency, which reflected that the coagulation process by alum was not suitable to carry out in the acidic condition. The high concentration of H\u003csup\u003e+\u003c/sup\u003e existing under acidic conditions makes it more challenging to hydrolyze the carboxyl groups of organic molecules (Cao et al. \u003cspan class=\"CitationRef\"\u003e2010\u003c/span\u003e). The result was similar to the condition at pH 5 by alum. Low pH may cause NOM solubility depletion and coagulation performance reduction if the primary process relies on charge neutralization (Dayarathne et al. \u003cspan class=\"CitationRef\"\u003e2021\u003c/span\u003e). Alum was more effective at reducing colour and COD concentrations as the pH went from 5 to 10, but it became less effective after reaching pH 12.\u003c/p\u003e\n \u003cp\u003eThe COD reduction and decolorization efficiency of alum in coagulation process were similar to Fe\u003csub\u003e2\u003c/sub\u003e(SO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e, which increased from pH 3 to pH 10. Metal ions tend to precipitate as amorphous hydroxides as pH increases. These colloidal hydroxides can adsorb other soluble species, leading to charge neutralization and destabilization in suspended colloidal systems (Dayarathne et al. \u003cspan class=\"CitationRef\"\u003e2021\u003c/span\u003e). Based on the results, it has been revealed that pH 10.0 is optimal for the alum and Fe\u003csub\u003e2\u003c/sub\u003e(SO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e in the coagulation process. The formation of the bonding flock particles using alum and Fe\u003csub\u003e2\u003c/sub\u003e(SO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e involves the presence of alkalinity in the water, which are aluminum hydroxide [Al(OH)\u003csub\u003e3\u003c/sub\u003e] and ferric hydroxide [Fe(OH)\u003csub\u003e3\u003c/sub\u003e], as shown in Eq.\u0026nbsp;(\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e) and Eq.\u0026nbsp;(\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e) (Pal \u003cspan class=\"CitationRef\"\u003e2017\u003c/span\u003e).\u003c/p\u003e\n \u003cdiv class=\"Equation\" id=\"Equ1\"\u003e\n \u003cdiv class=\"mathdisplay\" id=\"FileID_Equ1\" name=\"EquationSource\"\u003e$${Al}_{2}{(SO}_{4}{)}_{3}+6 NaOH\\to 2 Al{\\left(OH\\right)}_{3}+3 {Na}_{2}{SO}_{4}$$\u003c/div\u003e\n \u003cdiv class=\"EquationNumber\"\u003e1\u003c/div\u003e\n \u003c/div\u003e\n \u003cdiv class=\"Equation\" id=\"Equ2\"\u003e\n \u003cdiv class=\"mathdisplay\" id=\"FileID_Equ2\" name=\"EquationSource\"\u003e$${Fe}_{2}{(SO}_{4}{)}_{3}+6 NaOH\\to 2 Fe{\\left(OH\\right)}_{3}+3 {Na}_{2}{SO}_{4}$$\u003c/div\u003e\n \u003cdiv class=\"EquationNumber\"\u003e2\u003c/div\u003e\n \u003c/div\u003e\n \u003cp\u003eZayas et al. (\u003cspan class=\"CitationRef\"\u003e2007\u003c/span\u003e) obtained the highest removal percentages of COD, colour, and turbidity for anaerobically treated vinasse by FeCl\u003csub\u003e3\u003c/sub\u003e under slightly alkaline conditions. The COD reduction and decolorization efficiency of the coagulation process by CuSO\u003csub\u003e4\u003c/sub\u003e increased from pH 3 to pH 8. The result was lower when the pH decreased to pH 10 and pH 12. Salts of divalent and trivalent metals can be very acidic due to the release of protons during the formation of hydroxy complexes, which lowers the pH (Matilainen et al. 2010). The minimum COD reduction and decolorization efficiency was achieved for the pH value of 12.0 by alum, Fe\u003csub\u003e2\u003c/sub\u003e(SO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e and CuSO\u003csub\u003e4\u003c/sub\u003e. Under the highly alkaline condition, the surface electrical property turned negative, lowering the capability of charge neutralization (Cao et al. \u003cspan class=\"CitationRef\"\u003e2010\u003c/span\u003e). The coagulation process has been extensively studied in vinasse treatment using FeCl\u003csub\u003e3\u003c/sub\u003e, and this study provides an additional option for vinasse treatment in coagulation/flocculation processes.\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv class=\"Section3\" id=\"Sec14\"\u003e\n \u003ch2\u003e3.1.2 Effect of coagulant dosage on coagulation process\u003c/h2\u003e\n \u003cp\u003eThe coagulation process\u0026apos;s performance was assessed using various coagulant dosages. Figure \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e displays vinasse\u0026apos;s COD reduction and decolorization efficiency in the coagulation process at different coagulant dosage conditions under the optimum pH of the coagulants. The optimum coagulant dosage of alum, Fe\u003csub\u003e2\u003c/sub\u003e(SO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e and CuSO\u003csub\u003e4\u003c/sub\u003e is 1.0 g/L. It was reported that increasing the coagulant dosage from 5 to 15 g/L in the treatment of high strength raw vinasse can increase total organic carbon (TOC) removal (Fagier et al. 2016). The charge neutralization explains the occurrence of the optimal coagulant dose. The coagulant reacted with negatively charged colloids and neutralized their charges, promoting the destabilization of the colloids (Zhang et al. \u003cspan class=\"CitationRef\"\u003e2017b\u003c/span\u003e). Fe\u003csub\u003e2\u003c/sub\u003e(SO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e achieved the highest COD reduction and decolorization efficiency among the three coagulants, which are 73.7% and 96.3%. Many studies found ferric salts better than aluminium salts at removing natural organic matter (NOM). The flock particles (Fe(OH)\u003csub\u003e3\u003c/sub\u003e) or ferric hydroxides have a significantly higher density than the alum flocks. As a result, they can be quickly removed from the solution by sedimentation. When the coagulant dosage was increased to 2.0 g/L, however, the COD reduction and decolorization efficiency decreased to 58.0% and 70.8%, respectively. The excessive coagulants can lead to the re-stabilization of the suspended particles, and thus the treatment efficiency was reduced (Abujazar et al. \u003cspan class=\"CitationRef\"\u003e2022\u003c/span\u003e). Underdosing promotes the formation of colloidal particles, while overdosing pollutes wastewater by increasing turbidity, organic load, and slurry volume, expanding treatment costs (Alazaiza et al. \u003cspan class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv class=\"Section3\" id=\"Sec15\"\u003e\n \u003ch2\u003e3.1.3 Effect of initial COD concentration on coagulation process\u003c/h2\u003e\n \u003cp\u003ePractical application with the coagulation process shows that the initial COD concentration severely influences the reduction\u0026apos;s effectiveness. Therefore, the range for the initial concentration is crucial before starting the experiments. The increase of initial COD concentration is simultaneous to the increase of colour concentration and turbidity. Figure \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e shows the effect of initial COD concentration using Fe\u003csub\u003e2\u003c/sub\u003e(SO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e since it achieved the highest COD reduction and decolorization efficiency (73.7 and 96.3%). The COD reduction and decolorization efficiency was 41.5% and 81.5% at an initial COD concentration of 500 mg/L. The highest COD reduction and decolorization efficiency were obtained at 1000 mg/L. However, the COD reduction and decolorization efficiencies decreased at 3000 mg/L (12.2% and 31.6%). The increasing initial COD concentration and turbidity could provide more available pollutant molecules and produce more collisions between the coagulant and pollutants (Wang and Chen 2020). Thus, the required coagulant dosage could be reduced at high initial COD concentration conditions (high turbidity). Furthermore, low turbidity wastewater is needed for many coagulants because of the low collision frequency between contaminants and coagulants (Bolto and Gregory 2007). Meanwhile, the coagulation process was carried out based on a 1:1 ratio of coagulant dosage (g/L) and initial COD concentration (g/L). From Fig. \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e, the COD reduction and decolorization efficiency were 79.0\u0026thinsp;\u0026plusmn;\u0026thinsp;3.4% and 94.1\u0026thinsp;\u0026plusmn;\u0026thinsp;1.9%. The results revealed that the coagulant dosage of Fe\u003csub\u003e2\u003c/sub\u003e(SO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e in the coagulation process was directly proportional to the initial COD concentration. According to Zhao et al. (\u003cspan class=\"CitationRef\"\u003e2021\u003c/span\u003e), the dosages of coagulants will be added proportionally by increasing the initial concentration of the wastewater until complete charge neutralization has occurred at a given dose of coagulants. When charge neutralization is the primary mechanism, the efficiency decreases as dosage increases. Thus, optimizing dosing rates can provide additional cost savings while reducing sludge volume and treatment costs.\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec16\"\u003e\n \u003ch2\u003e3.2 Sequencing batch biofilm reactor (SBBR)\u003c/h2\u003e\n \u003cp\u003eThe SBBR was monitored for 28 operational days for the acclimatization phase, followed by 35 operational days for five batches of the cycle. SBBR was used to determine how substrate loading concentration affected COD reduction and decolorization effectiveness. The COD reduction and decolorization efficiency are demonstrated in Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003e(a) and Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003e(b). The COD reduction and decolorization efficiency achieved up to 80.4\u0026thinsp;\u0026plusmn;\u0026thinsp;4.0% and 92.2\u0026thinsp;\u0026plusmn;\u0026thinsp;3.7% after 7 days of reaction time under 1.0 g/L of substrate loading concentration. The COD reduction and decolorization efficiency increased to 84.0\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2% and 94.8\u0026thinsp;\u0026plusmn;\u0026thinsp;3.8%, respectively, when the substrate loading concentration was changed to 2.0 g/L. When operating at a substrate loading concentration of 3.0 g/L, the SBBR could lower COD to 86.6\u0026thinsp;\u0026plusmn;\u0026thinsp;4.3% and effectively decolorize the wastewater up to 94.6\u0026thinsp;\u0026plusmn;\u0026thinsp;3.8%. However, only 75.8\u0026thinsp;\u0026plusmn;\u0026thinsp;3.8% and 84.0\u0026thinsp;\u0026plusmn;\u0026thinsp;3.4% of the COD reduction and decolorization efficiency could be obtained using 4.0 g/L of substrate loading concentration, respectively. The longer duration needed for complete degradation of the substrate may be attributed to the high COD concentration produced as a result of an increase in the organic substrate loading concentration (Yap et al. \u003cspan class=\"CitationRef\"\u003e2022\u003c/span\u003e). Furthermore, the COD reduction and decolorization efficiency were 66.8\u0026thinsp;\u0026plusmn;\u0026thinsp;3.3% and 74.2\u0026thinsp;\u0026plusmn;\u0026thinsp;3.0% under 5.0 g/L of substrate loading concentration. The high substrate loading concentration resulted in excess substrates and a saturated state, which inhibited microbes. Due to the high amount of substrate, microbes could not completely break down, and the COD reduction and decolorization were less effective.\u003c/p\u003e\n \u003cp\u003eZero-order, first-order, and second-order kinetic models were used to determine the COD reduction and decolorization efficiency in treating vinasse. Eq. 3, Eq. (4), and Eq. (5) show the kinetic models (Sponza and Işik 2004).\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003cdiv align=\"left\" class=\"colspec\"\u003e\u003c/div\u003e\u003ctable border=\"1\" id=\"Taba\"\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\({\\text{S}}_{t}={S}_{0}-{k}_{0}t\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e(3)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(-ln\\left(\\frac{{\\text{S}}_{t}}{{S}_{0}}\\right)={k}_{1}t\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(4)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\frac{1}{{S}_{t}}=\\frac{1}{{S}_{0}}+{k}_{2}t\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e(5)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cp\u003eWhere S\u003csub\u003et\u003c/sub\u003e is the COD concentration at time t (mg/L), S\u003csub\u003e0\u003c/sub\u003e is the initial COD concentration (mg/L), t is the operational day, k\u003csub\u003e0\u003c/sub\u003e, k\u003csub\u003e1\u003c/sub\u003e, and k\u003csub\u003e2\u003c/sub\u003e are the zero (mg//L∙day), first (day\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) and second kinetic rate constant (L/mg∙day), respectively. Tables\u0026nbsp;1 and Table\u0026nbsp;2 demonstrate regression coefficients (R\u003csup\u003e2\u003c/sup\u003e) and reaction rate constants (k) for zero-order, first-order, and second-order kinetic models in the COD reduction and decolorization efficiency. The best fit was with the first-order kinetic model, which had the highest R\u003csup\u003e2\u003c/sup\u003e value. A similar result was obtained from (Kee et al. 2022b) in the recirculated sequencing batch reactor that the pseudo-first-order kinetic model was the best fit for the COD reduction. The highest COD reduction rate constant (k\u003csub\u003e1\u003c/sub\u003e\u003csup\u003eCOD\u003c/sup\u003e) was 0.1411 day\u003csup\u003e-1\u003c/sup\u003e under a substrate loading concentration of 3.0 g/L. The k\u003csub\u003e1\u003c/sub\u003e\u003csup\u003eCOD\u003c/sup\u003e was 1.79 times higher than when it was 1.0 g/L (0.0786 day\u003csup\u003e-1\u003c/sup\u003e) and 2.66 times higher than 5.0 g/L (0.0531 day\u003csup\u003e-1\u003c/sup\u003e). The variation in k\u003csub\u003e1\u003c/sub\u003e\u003csup\u003eCOD\u003c/sup\u003e associated with various substrate concentrations was attributed to the influence of microbial activity on the reactor performance. Besides, the highest decolorization rate constant (k\u003csub\u003e1\u003c/sub\u003e\u003csup\u003eColour\u003c/sup\u003e) was 0.28471 day\u003csup\u003e-1\u003c/sup\u003e under substrate loading concentration of 2.0 g/L, which was 1.02 and 4.64 times higher than that of 1.0 g/L (0.2791 day\u003csup\u003e-1\u003c/sup\u003e) and 5.0 g/L (0.0614 day\u003csup\u003e-1\u003c/sup\u003e), respectively. The result revealed that the decolorization rate was similar under low substrate loading concentrations (1.0 g/L and 2.0 g/L) and starting decreased when added the substrate loading concentration to the SBBR (\u0026gt;\u0026thinsp;2.0 g/L).\u003c/p\u003e\n \u003cdiv\u003e\n \u003cdiv\u003e\n \u003cp\u003eANOVA provided statistical evidence that demonstrated the effect of substrate loading concentration on the COD reduction and decolorization efficiency. The ANOVA results showed a significant difference between the five stages of substrate loading concentration (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05). In contrast, the Tukey post hoc test revealed no statistically significant difference in COD reduction efficiency between the 1.0 and 2.0 g/L, 1.0 and 3.0 g/L, 1.0 and 4.0 g/L, and 2.0 and 3.0 g/L groups. The results indicated that the slight increase in substrate loading concentration possessed little influence on the COD reduction efficiency (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05). The Tukey post hoc test yielded a similar result in determining the significant difference of specific substrate loading concentration in decolorization efficiency. However, the groups of 1.0 and 4.0 g/L revealed a significant difference. The result could refer to the decolorization efficiency decreased drastically from 1.0 to 4.0 g/L of substrate loading concentration\u003c/p\u003e\n \u003cdiv class=\"Section3\" id=\"Sec17\"\u003e\n \u003ch2\u003e3.2.1 UV\u0026ndash;Vis spectra analysis\u003c/h2\u003e\n \u003cp\u003eFigure \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e displays the impact of substrate loading concentration on UV-vis absorption spectra (190 to 500 nm) from day 1 to day 7. These results demonstrated that the absorbance bands had decreased after 7 days of reaction time. The results showed that the absorbance peak intensity at 270 nm decreased rapidly after 7 days of reaction time, representing the degradation of organic compounds (Arreola et al. \u003cspan class=\"CitationRef\"\u003e2020\u003c/span\u003e). The absorbance reduction reached 100% when considering 270 nm as the reference wavelength at the substrate loading concentration of 1.0 g/L after seven days of reaction time. However, the absorbance reduction decreased gradually to 78.2%, 62.7%, 48.5%, and 27.1% when increased the substrate loading concentration to 2.0 g/L, 3.0 g/L, 4.0 g/L, and 5.0 g/L of substrate loading concentration, respectively. Moreover, the absorbance peak intensity of 192\u0026ndash;198 nm gradually decreased, especially in Fig. \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e(a), Fig. \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e(b), and Fig. \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e(d). The peak (\u0026lambda;\u003csub\u003emax\u003c/sub\u003e) observed at 203 nm might refer to the ethanol in the vinasse (Kee et al. \u003cspan class=\"CitationRef\"\u003e2022a\u003c/span\u003e). After 7 days of reaction time, the absorbance at 194 nm decreased from 1.451 to 0.626 (56.9%) when the substrate loading concentration was 1.0 g/L. The absorbance at 194 nm decreased from 1.451 to 0.626 after 7 days of reaction time under 1.0 g/L of substrate loading concentration, which achieved 56.9% of absorbance reduction. Furthermore, the absorbance reduction reduced to 40.6% and 25.3% when added substrate loading concentration to 2.0 g/L and 4.0 g/L, respectively. Under substrate loading concentrations of 3.0 g/L and 5.0 g/L, the \u0026lambda;\u003csub\u003emax\u003c/sub\u003e was not observed in the UV-vis spectra of 192\u0026ndash;198 nm, as shown in Fig. \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e(c) and Fig. \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e(e). It could be related to the maximum absorbance limit (\u0026le;\u0026thinsp;3.0) and the application of a high dilution factor.\u003c/p\u003e\n \u003c/div\u003e\n \u003c/div\u003e\n \u003cdiv class=\"Section2\" id=\"Sec18\"\u003e\n \u003ch2\u003e3.3 Combined sequential process of coagulation and SBBR\u003c/h2\u003e\n \u003cp\u003eThe results of COD reduction and decolorization efficiency, as presented in Table \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e, were related to the treatment performances of the combined process of coagulation and SBBR under optimized conditions. The SBBR-CP outperformed the CP-SBBR in terms of COD removal and decolorization efficiencies. For the approaches of SBBR-CP, the COD reduction (86.6%) and decolorization (93.0%) were achieved in the first approach of coagulation. The results improved to 97.5% of COD reduction and 99.4% decolorization after the SBBR process. It could be observed that the SBBR could remove most of the organic compounds and turbidity in the vinasse through biodegradation. The growth of microbial attachment in the biofilm can enhance the degradation of COD concentration through the aeration process (Guo et al. \u003cspan class=\"CitationRef\"\u003e2019\u003c/span\u003e). Besides, the CP-SBBR obtained high reduction efficiencies, resulting in 81.2% of COD reduction and 91.1% of decolorization. The outstanding performance of the coagulation could be related to the rapid reaction of charge neutralization between the coagulants and vinasse (Crini and Lichtfouse 2018). Further degradation by using the SBBR was achieved, and the COD reduction and decolorization reached 96.3% and 99.3%, respectively. Thus, it could be said that both combinations of the coagulation process and SBBR could maximize the reduction efficiency, where the approach of SBBR-CP achieved a slightly better result when compared to CP-SBBR. It is recommended to apply combined processes because single technology has difficulty managing vinasse due to their high organic and complex wastewater containing recalcitrant organics and persistent colour (Gebreeyessus et al. 2019).\u0026nbsp;\u003c/p\u003e\n \u003ctable border=\"1\" id=\"Tab1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eRate constant, k and R\u003csup\u003e2\u003c/sup\u003e value in zero, first and second order under various substrate loading concentration in SBBR (COD reduction)\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eInitial COD concentration (g/L)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eZero order\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eFirst order\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eSecond order\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ek\u003csub\u003e0\u003c/sub\u003e\u003csup\u003eCOD\u003c/sup\u003e (mg//L∙day)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eR\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ek\u003csub\u003e1\u003c/sub\u003e\u003csup\u003eCOD\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003e(day\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eR\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ek\u003csub\u003e2\u003c/sub\u003e\u003csup\u003eCOD\u003c/sup\u003e (L/mg∙day)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eR\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e35.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.8882\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.0786\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.9224\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3 x 10\u003csup\u003e\u0026minus;\u0026thinsp;4\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.8085\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e54.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.6464\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.0962\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.731\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3 x 10\u003csup\u003e\u0026minus;\u0026thinsp;4\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.7924\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e102.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.9283\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.1411\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.9644\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2 x 10\u003csup\u003e\u0026minus;\u0026thinsp;4\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.9477\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e169.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.9681\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.1115\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.9878\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9 x 10\u003csup\u003e\u0026minus;\u0026thinsp;5\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.9505\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e117.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.9595\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.0531\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.9504\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4 x 10\u003csup\u003e\u0026minus;\u0026thinsp;5\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.7693\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003ctable border=\"1\" id=\"Tab2\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eRate constant, k and R\u003csup\u003e2\u003c/sup\u003e value in zero, first and second order under various initial substrate loading concentration in SBBR (decolourisation)\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eInitial COD concentration (g/L)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eZero order\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eFirst order\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eSecond order\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ek\u003csub\u003e0\u003c/sub\u003e\u003csup\u003eColour\u003c/sup\u003e (mg//L∙day)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eR\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ek\u003csub\u003e1\u003c/sub\u003e\u003csup\u003eColour\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003e(day\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eR\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ek\u003csub\u003e2\u003c/sub\u003e\u003csup\u003eColour\u003c/sup\u003e (L/mg∙day)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eR\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e227\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.8465\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.2791\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.9529\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4 x 10\u003csup\u003e\u0026minus;\u0026thinsp;4\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.9822\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e337\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.6878\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.2847\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.9067\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3 x 10\u003csup\u003e\u0026minus;\u0026thinsp;4\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.9683\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e273\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.8408\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.1691\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.9334\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 x 10\u003csup\u003e\u0026minus;\u0026thinsp;4\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.986\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e560\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.9276\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.1303\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.9706\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3 x 10\u003csup\u003e\u0026minus;\u0026thinsp;5\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.9661\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e402\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.9754\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.0614\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.985\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9 x 10\u003csup\u003e\u0026minus;\u0026thinsp;6\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.9869\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003ctable border=\"1\" id=\"Tab3\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eThe COD reduction and decolourisation efficiency with the combined process of coagulation and SBBR under optimized conditions\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\" colspan=\"4\"\u003e\n \u003cp\u003eSSBR-CP\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eParameter\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eInitial concentration\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1st approach\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1st\u003c/p\u003e\n \u003cp\u003ereduction (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2nd approach\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2nd\u003c/p\u003e\n \u003cp\u003ereduction (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eOverall reduction efficiency (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCOD (mg/L)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3584\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e482\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e86.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e81.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e97.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eColour (Pt/Co)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13580\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e955\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e93.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e85\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e91.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e99.4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"4\"\u003e\n \u003cp\u003eCP-SSBR\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCOD (mg/L)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e565\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e81.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e110\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e80.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e96.3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eColour (Pt/Co)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11100\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e990\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e91.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e80\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e91.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e99.3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv class=\"Section2\" id=\"Sec19\"\u003e\n \u003ch2\u003e3.4 Comparison of the effectiveness of the combined processes with previous studies\u003c/h2\u003e\n \u003cp\u003eThe past and current studies on the combined process of vinasse treatment are summarized in Table \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e. The overall COD treatment efficiency of the previous studies achieved 82.8\u0026thinsp;\u0026plusmn;\u0026thinsp;14.4%, as shown in Table \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e. The result demonstrated that the combined process could provide excellent treatment efficiency on vinasse, similar to the current study. Notably, the combination of chemical coagulation, biodegradation, and photo-Fenton oxidation by Rodrigues et al. (\u003cspan class=\"CitationRef\"\u003e2017\u003c/span\u003e) showed high efficiency in reducing COD (91.0%). The treated wastewater could be reused in the anaerobic reactor. Combining chemical coagulation and photo-Fenton oxidation to treat vinasses resulted in a 69.2% reduction in COD, as reported by Guerreiro et al. (\u003cspan class=\"CitationRef\"\u003e2016\u003c/span\u003e).The coagulation process could enhance the effluent\u0026apos;s biodegradability and eliminate its toxicity to Vibrio fischeri. In addition, Zayas et al. (\u003cspan class=\"CitationRef\"\u003e2007\u003c/span\u003e) obtained the highest COD reduction efficiency (99.5%) through coagulation/flocculation and electrochemical processes. This finding indicated that the combined treatment could significantly reduce the biologically treated vinasse\u0026apos;s COD, colour, and turbidity. The combined process of ultrafiltration and nanofiltration with pre-coagulation was a promising technology for treating sugarcane vinasse, according to Silva et al. (2020). Implementing the combined process could provide a 94.0% COD reduction, but the treatment cost was relatively high due to the membrane fouling. Lebron et al. (\u003cspan class=\"CitationRef\"\u003e2020\u003c/span\u003ea) used processes of coagulation, microfiltration, and nanofiltration to reduce COD concentration by 99.5%. It reported that the possibility of membrane fouling could be minimized when increasing the floc sizes with the coagulant addition and improving the back transport velocity of particles. The application of Pleurotus sajor-caju, followed by electrochemical oxidation for vinasse treatment, achieved 71% of COD reduction (Vilar et al. \u003cspan class=\"CitationRef\"\u003e2018\u003c/span\u003e).\u003c/p\u003e\n \u003ctable border=\"1\" id=\"Tab4\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eSummary from the past studies and present study on combined process on vinasse treatment\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eTreatments\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eWastewater\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eApproach 1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eApproach 2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eOverall COD treatment efficiency (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eReferences\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCOD reduction (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDecolourisation / Turbidity (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCOD reduction (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDecolourisation / Turbidity (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eChemical coagulation, biodegradation, and photo-Fenton oxidation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eSugarcane vinasse\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eChemical coagulation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eSequencing batch reactor and photo-Fenton oxidation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003e91.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003e(Rodrigues et al. \u003cspan class=\"CitationRef\"\u003e2017\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e43.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e99.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e83.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e100.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eChemical coagulation and photo-Fenton oxidation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eSugarcane vinasse\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003ePhoto-Fenton oxidation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eChemical coagulation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003e69.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003e(Guerreiro et al. \u003cspan class=\"CitationRef\"\u003e2016\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e63.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e99.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e43.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e94.3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eCoagulation/flocculation and electrochemical processes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eBiologically treated vinasse\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eCoagulation/flocculation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eElectrochemical processes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003e99.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003e(Zayas et al. \u003cspan class=\"CitationRef\"\u003e2007\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e84.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e99.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e97.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e87.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eProcess of ultrafiltration and nanofiltration with pre-coagulation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eSugarcane vinasse\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eCoagulation-ultrafiltration\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eNanofiltration\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003e94.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003e(Silva et al. 2020)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e46.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e94.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e90.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e95.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eCoagulation-Microfiltration-Nanofiltration\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eSugarcane vinasse\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eCoagulation-Microfiltration\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eNanofiltration\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003e99.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003e(Lebron et al. \u003cspan class=\"CitationRef\"\u003e2020\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e71.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e68.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e98.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e99.8\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eCombined biological \u0026ndash; Electrochemical oxidation treatment\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eSugarcane vinasse\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003ePleurotus sajor-caju (Biodegradation)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eElectrochemical oxidation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003e80.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003e(Vilar et al. \u003cspan class=\"CitationRef\"\u003e2018\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e50.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e96.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e61.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e92.9\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eCombined ultrasound and heterogeneous photocatalysis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003ePisco vinasse\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eHeterogeneous photocatalysis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eUltrasound\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003e70.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003e(Poblete et al. 2020)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e59.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e40.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e26.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14.2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eAerobic fungal growth followed by ozonation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eAnaerobically digested vinasse\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eAerobic Fungal Growth\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eOzonation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003e59.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003e(Reis et al. \u003cspan class=\"CitationRef\"\u003e2019\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e40.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e31.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eUpflow anaerobic filter-reactor and\u003c/p\u003e\n \u003cp\u003eozonation process\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eRaw vinasse (sugar factory)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eAnaerobic digestion\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eOzonation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003e82.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003e(Cabrera-D\u0026iacute;az et al. \u003cspan class=\"CitationRef\"\u003e2016\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e82.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e29.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e93.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eCombined coagulation and submerged bed biofilm reactor\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eSugarcane vinasse\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eSequencing batch biofilm reactor\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eCoagulation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003e97.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eThis study\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e86.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e93.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e81.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e91.1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003c/p\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003eThe toxicity of vinasse had been eliminated through lactuca sativa and raphidocelis subcapitata bioassays. Poblete et al. (2020) elucidated that combining ultrasound and heterogeneous photocatalysis could be a practical alternative for treating pisco vinasse because of the energy efficiency and relatively high pollutant-removal rates. Furthermore, Reis et al. (\u003cspan class=\"CitationRef\"\u003e2019\u003c/span\u003e) reported that the aerobic fungal growth could remove over 80% of Kjeldahl-Nitrogen, followed by ozonation that depleted the phenolic compounds. Lastly, Cabrera-D\u0026iacute;az et al. (\u003cspan class=\"CitationRef\"\u003e2016\u003c/span\u003e) reported that the upflow anaerobic filter-reactor achieved high COD reduction with methane production, while the ozonation process played an essential role in the complete decolorization of anaerobically digested vinasse. The 97.5% maximum COD reduction reported in the current study compared to previous studies was excellent. High COD reduction and decolorization were obtained through either coagulation or SBBR as the first approach in the treatment of sugarcane vinasse. Based on other studies, most of the combined processes still focus on combining chemical and physical processes. These phenomena could be explained by the high removal efficiency and fast reaction in the physio-chemical techniques. Typically, biological treatment requires a more prolonged start-up phase due to the slow growth of bacteria and a long hydraulic retention period (HRT). Thus, this study\u0026apos;s combination of chemical and biological methods provided additional insight for future treatment in sugarcane vinasse. As a result, the effluent quality was enhanced, allowing for its subsequent reuse in producing bioethanol.\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn the current study, coagulation and SBBR showed to be promising strategies in treating sugarcane vinasse, either in a single or combination process. First, the optimized coagulation process was obtained using Fe\u003csub\u003e2\u003c/sub\u003e(SO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e3\u003c/sub\u003e at initial pH 10, resulting in the COD reduction and decolorization efficiency of 79.0\u0026thinsp;\u0026plusmn;\u0026thinsp;3.4% and 94.1\u0026thinsp;\u0026plusmn;\u0026thinsp;1.9%, respectively. The optimum proportion between the initial COD concentration (g/L) and coagulant dosage (g/L) was a 1:1 ratio. Then, the maximum COD reduction (86.6\u0026thinsp;\u0026plusmn;\u0026thinsp;4.3%) and decolorization (94.6\u0026thinsp;\u0026plusmn;\u0026thinsp;3.8%) were achieved using SBBR at 3.0 g/L of substrate loading concentration. Furthermore, kinetic studies of SBBR were evaluated, and the first-order kinetic model was best fitted among zero, first, and second-order kinetic models. From the UV\u0026ndash;Vis analysis, the absorbance bands at 270 nm and 192-198nm were diminished over time, which indicated the degradation of organic and alcohol compounds in SBBR. Next, two conditions of combined processes, CP\u0026ndash;SBBR and SBBR\u0026ndash;CP, were assessed. These two combined processes carried out at optimum operating parameters showed 97.5 and 96.3% COD reduction, with 99.4 and 99.3% decolorization for SBBR-CP and CP-SBBR, respectively. Thus, combined sequential processes of coagulation and SBBR was recommended for implementation in sugarcane vinasse treatment, where the approach of SBBR-CP achieved a slightly better result when compared to CP-SBR.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors would like to express their sincere gratitude to the Faculty of Civil Engineering Technology Universiti Malaysia Perlis (UniMAP), and Fermpro Industries.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll data generated or analysed during this study are included in this published article.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo funding was received to assist with the preparation of this manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors’ contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eConceptualization and methodology were prepared by Yee-Shian Wong and Wei-Chin Kee. Formal analysis and investigation were performed by Yee-Shian Wong, Wei-Chin Kee, and Audrey Chai. The first draft of the manuscript was written by Wei-Chin Kee, and all authors commented on previous versions of the manuscript. Resources and supervision were provided by Yee-Shian Wong, Soon-An Ong, Nabilah Aminah Lutpi, Sung-Ting Sam, Farrah Aini Dahalan, and Kim-Mun Eng. All authors read and approved the final manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAbujazar MSS, Karaağa\u0026ccedil;SU, Abu AmrSS et al (2022) Recent advancement in the application of hybrid coagulants in coagulation-flocculation of wastewater: A review. J Clean Prod 345. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.jclepro.2022.131133\u003c/span\u003e\u003cspan address=\"10.1016/j.jclepro.2022.131133\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAlazaiza MYD, AlbahnasawiA AliGAM et al (2022) Application of Natural Coagulants for Pharmaceutical Removal from Water and Wastewater: A Review. Water (Switzerland) 14:1\u0026ndash;16. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3390/w14020140\u003c/span\u003e\u003cspan address=\"10.3390/w14020140\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eArreola AR, TizapaMS ZuritaF et al (2020) Treatment of tequila vinasse and elimination of phenol by coagulation\u0026ndash;flocculation process coupled with heterogeneous photocatalysis using titanium dioxide nanoparticles. Environ Technol (United Kingdom) 41:1023\u0026ndash;1033. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1080/09593330.2018.1518994\u003c/span\u003e\u003cspan address=\"10.1080/09593330.2018.1518994\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBolto B, GregoryJ (2007) Organic polyelectrolytes in water treatment. Water Res 41:2301\u0026ndash;2324. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.watres.2007.03.012\u003c/span\u003e\u003cspan address=\"10.1016/j.watres.2007.03.012\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCabrera-D\u0026iacute;az A, Pereda-ReyesI, Due\u0026ntilde;as-MorenoJ et al (2016) Combined treatment of vinasse by an upflow anaerobic filter-reactor and ozonation process. Brazilian J Chem Eng 33:753\u0026ndash;762. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1590/0104-6632.20160334s20150268\u003c/span\u003e\u003cspan address=\"10.1590/0104-6632.20160334s20150268\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCao BC, GaoBY, XuCH et al (2010) Effects of pH on coagulation behavior and floc properties in Yellow River water treatment using ferric based coagulants. Chin Sci Bull 55:1382\u0026ndash;1387. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s11434-010-0087-5\u003c/span\u003e\u003cspan address=\"10.1007/s11434-010-0087-5\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCarpanez TG, MoreiraVR, AssisIR AmaralMCS (2022) Sugarcane vinasse as organo-mineral fertilizers feedstock: Opportunities and environmental risks. Sci Total Environ 832:154998. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.scitotenv.2022.154998\u003c/span\u003e\u003cspan address=\"10.1016/j.scitotenv.2022.154998\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCarvajal-Zarrabal O, Nolasco-Hip\u0026oacute;litoC Barradas-DermitzDM et al (2012) Treatment of vinasse from tequila production using polyglutamic acid. J Environ Manage 95:S66\u0026ndash;S70. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.jenvman.2011.05.001\u003c/span\u003e\u003cspan address=\"10.1016/j.jenvman.2011.05.001\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChai A, WongYS, OngSA et al (2021) Haldane-Andrews substrate inhibition kinetics for pilot scale thermophilic anaerobic degradation of sugarcane vinasse. Bioresour Technol 336:125319. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.biortech.2021.125319\u003c/span\u003e\u003cspan address=\"10.1016/j.biortech.2021.125319\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCrini G (2018) LichtfouseE Wastewater Treatment: An Overview. pp\u0026nbsp;1\u0026ndash;21\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDavid C, NarlawarR ArivazhaganM (2016) Performance Evaluation of Moringa oleifera Seed Extract (MOSE) in Conjunction with Chemical Coagulants for Treating Distillery Spent Wash. Indian Chem Eng 58:189\u0026ndash;200. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1080/00194506.2015.1006147\u003c/span\u003e\u003cspan address=\"10.1080/00194506.2015.1006147\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDayarathne HNP, AngoveMJ AryalR et al (2021) Removal of natural organic matter from source water: Review on coagulants, dual coagulation, alternative coagulants, and mechanisms. J Water Process Eng 40:101820. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.jwpe.2020.101820\u003c/span\u003e\u003cspan address=\"10.1016/j.jwpe.2020.101820\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEl-Shafai SA, ZahidWM (2013) Performance of aerated submerged biofilm reactor packed with local scoria for carbon and nitrogen removal from municipal wastewater. Bioresour Technol 143:476\u0026ndash;482. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.biortech.2013.06.027\u003c/span\u003e\u003cspan address=\"10.1016/j.biortech.2013.06.027\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEspa\u0026ntilde;a-Gamboa E, Mijangos-CortesJ Barahona-PerezL et al (2011) Vinasses: Characterization and treatments. Waste Manag Res 29:1235\u0026ndash;1250. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1177/0734242X10387313\u003c/span\u003e\u003cspan address=\"10.1177/0734242X10387313\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFagier MA, AliEA, TayKS AbasMRB (2016) Mineralization of organic matter from vinasse using physicochemical treatment coupled with Fe2+-activated persulfate and peroxymonosulfate oxidation. Int J Environ Sci Technol 13:1189\u0026ndash;1194. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s13762-016-0963-x\u003c/span\u003e\u003cspan address=\"10.1007/s13762-016-0963-x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFito J, TeferaN VanHulleSWH (2019) Sugarcane biorefineries wastewater: bioremediation technologies for environmental sustainability. Chem Biol Technol Agric 6:1\u0026ndash;13. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1186/s40538-019-0144-5\u003c/span\u003e\u003cspan address=\"10.1186/s40538-019-0144-5\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFuess LT, GarciaML (2014) Implications of stillage land disposal: A critical review on the impacts of fertigation. J Environ Manage 145:210\u0026ndash;229. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.jenvman.2014.07.003\u003c/span\u003e\u003cspan address=\"10.1016/j.jenvman.2014.07.003\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGebreeyessus GD, MekonenA AlemayehuE (2019) A review on progresses and performances in distillery stillage management. J Clean Prod 232:295\u0026ndash;307. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.jclepro.2019.05.383\u003c/span\u003e\u003cspan address=\"10.1016/j.jclepro.2019.05.383\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eG\u0026oacute;mez-Villalba B, CalvoC VilchezR et al (2006) TGGE analysis of the diversity of ammonia-oxidizing and denitrifying bacteria in submerged filter biofilms for the treatment of urban wastewater. Appl Microbiol Biotechnol 72:393\u0026ndash;400. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s00253-005-0272-7\u003c/span\u003e\u003cspan address=\"10.1007/s00253-005-0272-7\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGuerreiro LF, RodriguesCSD DudaRM et al (2016) Treatment of sugarcane vinasse by combination of coagulation/flocculation and Fenton\u0026rsquo;s oxidation. J Environ Manage 181:237\u0026ndash;248. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.jenvman.2016.06.027\u003c/span\u003e\u003cspan address=\"10.1016/j.jenvman.2016.06.027\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGuo X, LiB ZhaoR et al (2019) Performance and bacterial community of moving bed biofilm reactors with various biocarriers treating primary wastewater effluent with a low organic strength and low C/N ratio. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.biortech.2019.121424\u003c/span\u003e\u003cspan address=\"10.1016/j.biortech.2019.121424\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Bioresour Technol 287:\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHoarau J, CaroY, GrondinI PetitT (2018) Sugarcane vinasse processing: Toward a status shift from waste to valuable resource. A review. J Water Process Eng 24:11\u0026ndash;25. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.jwpe.2018.05.003\u003c/span\u003e\u003cspan address=\"10.1016/j.jwpe.2018.05.003\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHussaini Jagaba A (2018) Wastewater Treatment Using Alum, the Combinations of Alum-Ferric Chloride, Alum-Chitosan, Alum-Zeolite and Alum- \u003cem\u003eMoringa Oleifera\u003c/em\u003eas Adsorbent and Coagulant. Int J Eng Manag 2:67. https://doi.org/10.11648/j.ijem.20180203.13\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eIsmail Z, AzizMMA MahmoodNAN et al (2018) Optimisation of a modified submerged bed biofilm reactor for biological oleochemical wastewater treatment. J Environ Manage 226:156\u0026ndash;162. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.jenvman.2018.08.003\u003c/span\u003e\u003cspan address=\"10.1016/j.jenvman.2018.08.003\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKee W-C et al (2022a) Photocatalytic Degradation of Sugarcane Vinasse Using ZnO Photocatalyst: Operating Parameters, Kinetic Studies, Phytotoxicity Assessments, and Reusability. Int J Environ Res 16. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s41742-021-00382-6\u003c/span\u003e\u003cspan address=\"10.1007/s41742-021-00382-6\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKee WC, WongYS OngSA et al (2022b) Insights into modified sequencing batch reactor for the treatment of sugarcane vinasse: role of recirculation process. Int J Environ Sci Technol. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s13762-022-03946-x\u003c/span\u003e\u003cspan address=\"10.1007/s13762-022-03946-x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKiani Deh Kiani M, ParsaeeM MahdavifarZ (2021) Biogas production from sugarcane vinasse at mesophilic and thermophilic temperatures by static granular bed reactor (SGBR). Sustain Energy Technol Assessments 48:101569. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.seta.2021.101569\u003c/span\u003e\u003cspan address=\"10.1016/j.seta.2021.101569\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLau YY, WongYS TengTT et al (2014) Coagulation-flocculation of azo dye acid orange 7 with green refined laterite soil. Chem Eng J 246:383\u0026ndash;390. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.cej.2014.02.100\u003c/span\u003e\u003cspan address=\"10.1016/j.cej.2014.02.100\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLebron YAR, MoreiraVR FurtadoTPB et al (2020) Vinasse treatment using hybrid tannin-based Coagulation-Microfiltration-Nanofiltration processes: Potential energy recovery, technical and economic feasibility assessment. Sep Purif Technol 248:117152. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.seppur.2020.117152\u003c/span\u003e\u003cspan address=\"10.1016/j.seppur.2020.117152\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMatilainen A, Veps\u0026auml;l\u0026auml;inenM Sillanp\u0026auml;\u0026auml;M (2010) Natural organic matter removal by coagulation during drinking water treatment: A review. Adv Colloid Interface Sci 159:189\u0026ndash;197. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.cis.2010.06.007\u003c/span\u003e\u003cspan address=\"10.1016/j.cis.2010.06.007\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOller I, MalatoS, S\u0026aacute;nchez-P\u0026eacute;rezJA (2011) Combination of Advanced Oxidation Processes and biological treatments for wastewater decontamination-A review. Sci Total Environ 409:4141\u0026ndash;4166. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.scitotenv.2010.08.061\u003c/span\u003e\u003cspan address=\"10.1016/j.scitotenv.2010.08.061\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePal P (2017) Chemical Treatment Technology\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePoblete R, CortesE, SalihogluG SalihogluNK (2020) Ultrasound and heterogeneous photocatalysis for the treatment of vinasse from pisco production. Ultrason Sonochem 61:104825. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.ultsonch.2019.104825\u003c/span\u003e\u003cspan address=\"10.1016/j.ultsonch.2019.104825\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRatna S, RastogiS KumarR (2021) Current trends for distillery wastewater management and its emerging applications for sustainable environment. J Environ Manage 290:112544. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.jenvman.2021.112544\u003c/span\u003e\u003cspan address=\"10.1016/j.jenvman.2021.112544\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eReis CER, BentoHBS AlvesTM et al (2019) Vinasse treatment within the sugarcane-ethanol industry using ozone combined with anaerobic and aerobic microbial processes. Environ - MDPI 6. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3390/environments6010005\u003c/span\u003e\u003cspan address=\"10.3390/environments6010005\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRodrigues CSD, NetoAR DudaRM et al (2017) Combination of chemical coagulation, photo-Fenton oxidation and biodegradation for the treatment of vinasse from sugar cane ethanol distillery. J Clean Prod 142:3634\u0026ndash;3644. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.jclepro.2016.10.104\u003c/span\u003e\u003cspan address=\"10.1016/j.jclepro.2016.10.104\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSilva AFR, BrasilYL, KochK AmaralMCS (2021) Resource recovery from sugarcane vinasse by anaerobic digestion \u0026ndash; A review. J Environ Manage 295:113137. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.jenvman.2021.113137\u003c/span\u003e\u003cspan address=\"10.1016/j.jenvman.2021.113137\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSilva SCda MoraviaMCSA, CoutoCF (2020) Combined Process of Ultrafiltration and Nanofiltration for Vinasse Treatment With and Without Pre-Coagulation. J Water Process Eng 36:101326. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.jwpe.2020.101326\u003c/span\u003e\u003cspan address=\"10.1016/j.jwpe.2020.101326\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSponza DT, IşikM (2004) Decolorization and inhibition kinetic of Direct Black 38 azo dye with granulated anaerobic sludge. Enzyme Microb Technol 34:147\u0026ndash;158. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.enzmictec.2003.10.006\u003c/span\u003e\u003cspan address=\"10.1016/j.enzmictec.2003.10.006\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTakeda PY, OliveiraCA EduardaM et al (2022) Enhancing the energetic potential of sugarcane biore fi nery exchanging vinasse and glycerol in sugarcane off-season in an anaerobic reactor. 195. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.renene.2022.06.128\u003c/span\u003e\u003cspan address=\"10.1016/j.renene.2022.06.128\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVilar DS, CarvalhoGO PupoMMS et al (2018) Vinasse degradation using Pleurotus sajor-caju in a combined biological \u0026ndash; Electrochemical oxidation treatment. Sep Purif Technol 192:287\u0026ndash;296. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.seppur.2017.10.017\u003c/span\u003e\u003cspan address=\"10.1016/j.seppur.2017.10.017\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang J, ChenX (2020) Removal of antibiotic resistance genes (ARGs) in various wastewater treatment processes: An overview. Crit Rev Environ Sci Technol 52:571\u0026ndash;630. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1080/10643389.2020.1835124\u003c/span\u003e\u003cspan address=\"10.1080/10643389.2020.1835124\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYap KL, HoLN OngSA et al (2022) Microbial fuel cell for simultaneous caffeine removal and bioelectricity generation under various operational conditions in the anodic and cathodic chambers. Environ Technol Innov 25:102158. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.eti.2021.102158\u003c/span\u003e\u003cspan address=\"10.1016/j.eti.2021.102158\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZayas T, R\u0026oacute;meroV SalgadoL et al (2007) Applicability of coagulation/flocculation and electrochemical processes to the purification of biologically treated vinasse effluent. Sep Purif Technol 57:270\u0026ndash;276. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.seppur.2007.04.019\u003c/span\u003e\u003cspan address=\"10.1016/j.seppur.2007.04.019\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang M, WangZ LiP et al (2017a) Bio-refractory dissolved organic matter and colorants in cassava distillery wastewater: Characterization, coagulation treatment and mechanisms. Chemosphere 178:259\u0026ndash;267. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.chemosphere.2017.03.065\u003c/span\u003e\u003cspan address=\"10.1016/j.chemosphere.2017.03.065\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang W, GaoH, HeJ et al (2017b) Removal of norfloxacin using coupled synthesized nanoscale zero-valent iron (nZVI) with H2O2 system: Optimization of operating conditions and degradation pathway. Sep Purif Technol 172:158\u0026ndash;167. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.seppur.2016.08.008\u003c/span\u003e\u003cspan address=\"10.1016/j.seppur.2016.08.008\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhao C, ZhouJ YanY et al (2021) Application of coagulation/flocculation in oily wastewater treatment: A review. Sci Total Environ 765:142795. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.scitotenv.2020.142795\u003c/span\u003e\u003cspan address=\"10.1016/j.scitotenv.2020.142795\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"environmental-science-and-pollution-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"espr","sideBox":"Learn more about [Environmental Science and Pollution Research](https://www.springer.com/journal/11356)","snPcode":"11356","submissionUrl":"https://submission.nature.com/new-submission/11356/3","title":"Environmental Science and Pollution Research","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Coagulation, Combined processes, Industrial effluent, Sequencing batch biofilm reactor, Sugarcane vinasse, Wastewater treatment","lastPublishedDoi":"10.21203/rs.3.rs-2007267/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-2007267/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eSugarcane vinasse has been widely reported due to the improper management that pollutes the environment. In this study, a combined coagulation and sequencing batch biofilm reactor (SBBR) seems to be a novel improvement for the treatment of sugarcane vinasse. This research focused on the optimal conditions of coagulation and SBBR and determined the abatement efficiency of sugarcane vinasse in combined sequential wastewater treatment. The coagulation process destabilizes the colloids in the aggregation and separates the supernatant by sedimentation and filtration, resulting in the maximum COD reduction (79.0\u0026thinsp;\u0026plusmn;\u0026thinsp;3.4%) and decolorization efficiency (94.1\u0026thinsp;\u0026plusmn;\u0026thinsp;1.9%) under the optimum conditions. Sequencing batch reactor (SBR) is a fill-and-draw activated sludge system, whereas SBBR is an integrated SBR that suspends activated sludge and connects growth processes into a biocarrier-filled system. SBBR showed great synergistic degradability, decreasing 86.6\u0026thinsp;\u0026plusmn;\u0026thinsp;4.3% COD concentration and 94.6\u0026thinsp;\u0026plusmn;\u0026thinsp;3.8% decolorization at 3.0 g/L of substrate loading concentration. Furthermore, kinetic studies of SBBR revealed that the first-order kinetic model was the best fitting model. The SBBR reaction was further investigated by ultraviolet-visible spectrophotometry (UV\u0026ndash;Vis). Then, SBBR followed by the coagulation process (SBBR\u0026ndash;CP) achieved 97.5% of COD reduction and 99.4% of decolorization, which was better than the coagulation process followed by SBBR (CP\u0026ndash;SBBR). This finding provides new insight into developing efficient combined sequential wastewater treatments in sugarcane vinasse.\u003c/p\u003e","manuscriptTitle":"Chemical and biological combined treatment for the sugarcane vinasse: Selection of parameters and performance studies","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2022-10-18 18:44:54","doi":"10.21203/rs.3.rs-2007267/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major Revision","date":"2022-12-07T04:23:39+00:00","index":"","fulltext":""},{"type":"reviewersInvited","content":"","date":"2022-10-24T12:57:46+00:00","index":"","fulltext":""},{"type":"reviewerAgreed","content":"","date":"2022-10-15T07:37:58+00:00","index":0,"fulltext":""},{"type":"editorInvited","content":"Environmental Science and Pollution Research","date":"2022-09-15T13:09:29+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2022-09-05T04:39:36+00:00","index":"","fulltext":""},{"type":"submitted","content":"Environmental Science and Pollution Research","date":"2022-08-31T10:17:46+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"environmental-science-and-pollution-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"espr","sideBox":"Learn more about [Environmental Science and Pollution Research](https://www.springer.com/journal/11356)","snPcode":"11356","submissionUrl":"https://submission.nature.com/new-submission/11356/3","title":"Environmental Science and Pollution Research","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"ba28bf87-1d29-4cdb-a837-ceb16fb96129","owner":[],"postedDate":"October 18th, 2022","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2023-10-16T20:35:33+00:00","versionOfRecord":{"articleIdentity":"rs-2007267","link":"https://doi.org/10.1007/s11356-023-27046-6","journal":{"identity":"environmental-science-and-pollution-research","isVorOnly":false,"title":"Environmental Science and Pollution Research"},"publishedOn":"2023-04-21 20:30:40","publishedOnDateReadable":"April 21st, 2023"},"versionCreatedAt":"2022-10-18 18:44:54","video":"","vorDoi":"10.1007/s11356-023-27046-6","vorDoiUrl":"https://doi.org/10.1007/s11356-023-27046-6","workflowStages":[]},"version":"v1","identity":"rs-2007267","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-2007267","identity":"rs-2007267","version":["v1"]},"buildId":"_2-kVJe1T_tPrBINL-cwx","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}