Vermiremediation of paper mill sludge with cow dung and tea waste amendments using epigeic earthworm Eisenia fetida (Savigny)

Abstract Vermiremediation of paper mill sludge (PMS) was done by Eisenia fetida after adding cow dung (CD) and tea waste (TW). In all, six reactors were prepared: R1 [CD (100%)], R2 [PMS: CD (1:2)], R3 [PMS: CD (1:1)], R4 [PMS: TW: CD (1:1:1)], R5 [PMS: TW: CD (1:2:1)] & R6 [PMS: TW: CD (2:1:1)]. A significant decrease in heavy metals was observed: Cd (37.2–58.2%), Cr (57.0-74.3%), Cu (67.3–79.8%), Ni (74.7–81.9%), Pb (78.8–83.4%) & Zn (71.2–77.4%); while heavy metal concentrations in earthworm tissues (mg.kg− 1) were recorded as: Cd (2.79–3.24), Cr (23.54–28.76), Cu (9.53–11.56), Ni (3.52–3.99), Pb (8.76–9.43) & Zn (23.12–29.72), after 60 days of study period. The Bioaccumulation factors (BAFs) of E.fetida was in the order: Ni > Cd > Cr > Pb > Zn > Cu. R3 obtained the maximum heavy metal removal (74.45%) while that in R4 (72.93%) also emphasized the use of tea waste in the bioremediation process. It was finally observed that cow dung and tea waste amendments favored the vermiremoval of heavy metals from paper mill sludge using Eisenia fetida.