Performance evaluation of vermifilter at different hydraulic loading rate using river bed material

The present work illustrates the potential of vermifilter using river bed material with application of wastewater at different hydraulic loading rates for the treatment. In addition, a comparative study was performed with vermifilter containing the earthworm species (Eisenia fetida) parallel to a geofilter (without earthworms) for the treatment of wastewater to achieve the requisite quality of the effluent. The wastewater was applied to the vermifilter and geofilter at four different hydraulic loading rates of 1.5, 2, 2.5 and 3.0 m3 m−2 d−1. Among these, optimum results were observed in case of hydraulic loading rate 2.5 m3 m−2 d−1. For this hydraulic loading rate, the removal efficiency of biochemical oxygen demand, total suspended solids and total dissolve solids with vermifilter were 96%, 90% and 82%, while in geofilter it was observed 70%, 79% and 56% respectively. In addition, riverbed material was found to be better as a media in vermifilter for better growth of earthworm biomass. The treated effluent and final vermicompost both were found to be rich in nitrate and phosphate which can be used for agriculture purpose.