Designing an activated sludge reactor to convert polluting gases from refinery effluent into biofertilizer

Abstract The purpose of designing a suitable laboratory reactor is to convert polluting gases from refinery effluent into biofertilizer. The activated sludge reactor designed in this research includes a cube-shaped tank made of glass with a volume of 5 L and the volume of the sedimentation pond was considered to be 5 L. The design of experiments using the method of one variable in each step. The effect of different parameters and concentrations of variables (inoculum concentration (0.1, 0.15 and 0.2 g.L− 1), ammonium sulfate concentration (0.1, 0.3 and 0.5 g.L− 1) and sodium phosphate ( 0.1, 0.3 and 0.5 g.L− 1) are measured separately on the amount of wastewater treatment. Wastewater treatment tests are investigated in a period of 14 days, and biological treatment of wastewater (BOD) and total organic carbon (TOC) are reduced by 71.27 and 48.98%, respectively. The results show that with the reduction of total dissolved solid (TDS), the electrical conductivity (EC) of water decreases by 48.58%. During this period, the concentration of H2S, NH3, CH4, and CO2 gases in the effluent has shown a decreasing trend, which has decreased by 30.08, 60.25, 71.42, and 80.95%, respectively.