Vermifiltration of Domestic Wastewater Using Eisenia Fetida: Performance Evaluation and Bioremediation Efficiency

Domestic wastewater contains biodegradable organic matter, suspended solids, dissolved substances and nutrients that may adversely affect receiving water bodies when discharged without adequate treatment. The present study evaluated the performance of a small-scale laboratory vermifilter using the earthworm Eisenia fetida and coconut/coir or agricultural-waste material combined with sand and gravel for domestic wastewater purification. The treatment system was developed as a low-cost biological filtration unit in which physical filtration, adsorption and earthworm-associated biological processes could occur simultaneously. The influent and vermifilter effluent were analyzed for pH, turbidity, total dissolved solids (TDS), total suspended solids (TSS), biochemical oxygen demand (BOD₅), chemical oxygen demand (COD), ammoniacal nitrogen (NH₃-N), nitrate nitrogen (NO₃-N) and phosphate. The pH increased from 6.70 to 7.38 after treatment. Turbidity decreased from 81.0 to 7.9 NTU, representing 90.25% removal. TDS decreased from 770 to 215 mg/L (72.08%), while TSS decreased from 235 to 119 mg/L (49.36%). BOD₅ decreased from 318 to 34 mg/L (89.31%), and COD decreased from 520 to 88 mg/L (83.08%). NH₃-N decreased from 40.0 to 5.3 mg/L (86.75%), NO₃-N from 18.0 to 7.2 mg/L (60.00%), and phosphate from 9.6 to 2.7 mg/L (71.88%). The results indicate that the laboratory-scale vermifilter was particularly effective in reducing turbidity, biodegradable organic matter and ammoniacal nitrogen. The findings demonstrate the potential of combining E. fetida with coconut/coir-based agricultural waste, sand and gravel as a simple and environmentally friendly approach for decentralized domestic wastewater treatment.