Sustainable pre-treatment of tempeh industry wastewater: Efficiency of vermifiltration in pollutant mitigation and compost production

This study investigated the efficacy of vermifiltration (VF) as a sustainable pre-treatment method for tempeh industry wastewater. Three lab-scale VF reactors using different earthworm feeds - cow dung (VF-1), tofu dregs (VF-2), and a combination of both (VF-3) - were used to evaluate their ability to reduce chemical oxygen demand (COD), biochemical oxygen demand (BOD₅), and total suspended solids (TSS), as well as pH. VF-3 exhibited superior performance, achieving reductions of 94.51 % in COD, 95.59 % in BOD₅, and 88.59 % in TSS with maintaining pH values between 6.73 and 6.87. The resulting vermicompost (VC) had high nutrient content, particularly in the VF-3 reactor, with values of 7.66 % C-organic, 1.19 % nitrogen (N), and a C/N ratio of 10.33, phosphate (P) 1.65 %, and potassium (K) of 0.37 %. Additionally, significant earthworm growth was noted in VF-3, suggesting enhanced organic matter breakdown. These results indicate that VF technology not only effectively reduces pollutants in wastewater but also produces nutrient-rich compost, offering a dual benefit for sustainable wastewater management in the tempeh industry.