A comparative study of macrophytes influence on performance of hybrid vermifilter for dairy wastewater treatment

Abstract

Population increase and speedy urbanization are two major driving factors for scarcity of water in present time. To fulfil such water demand, reuse of industrial wastewater is necessary after essential purification. Vermifilter coupled with macrophyte filter is one of the promising technology for the treatment of organics and nutrient rich wastewater. In the present study, various macrophytes have been planted in vermifilter to study their effect on pollutants removal efficiency. Four sets of reactors R1, R2, R3 and R4 were designed and each set of reactor consisted of two units: vertical flow (VF) and horizontal flow (HF) unit. R1, R2 and R3 were planted with Canna indica, Saccharum spontaneum and Typha angustifolia, respectively, whereas R4 was without any macrophyte. Earthworm Eisenia fetida was inserted in all the four reactors. VF units of all hybrid vermifilter were loaded with synthetic dairy wastewater at hydraulic loading rate (HLR) of 0.6 m d−1. Effluents were collected at the bottom of the VF unit and channelled to the HF unit. Final effluent was collected at the end of the HF unit. The order of average percentage removal of COD was R1 (82.8%) > R3 (78.9%) > R2 (75.5%) > R4 (69.4%). Organics and nutrients were targeted to remove in the filter as these pollutants make major fraction in real dairy wastewater compare to antibiotics and other emerging contaminants. Presence of very few kind and low amount of antibiotics in dairy wastewater like lincomycin, chlortetracycline, etc. have been reported in literature.