Stabilization of anarobic digestor sludge through vermicomposting

Abstract

In this study, efficiency of vermitechnology in stabilizing sludge without pre-treatment was studied. The sludge was directly introduced in the vermicomposting reactors after their withdrawal from the bio-methanation reactor installed for experimentation on domestic waste. One Liter (5% TS) sludge was loaded after every fourth day and it was discontinued after sixteen days. However, the chemical analysis of the compost was done till twentyfourth day. The present study also evaluated the potential of one indigenous Perionyx excavates (P.e.) and one exotic epigeic earthworm species Eisenia fetida (E.f). The results clearly elucidate that vermireactor with indigenous earthworms (P.e) gives over all comparable similar results with world wide known exotic species (E.f). The results of the study show a significant reduction in initial C/N ratio from an initial value of 19 to 9 for all reactors with earthworms, total organic matter (TOC) reduced by 50% and pH also reduced nearer to neutral, but increase in, total nitrogen (TN) 95%, NH4+-N reduced from 0.52% to 0.31% and NO3-N increased from 0 to 0.13%, total phosphorus (TP) increased from the initial concentration of 0.76% to 1.31%., However, removal efficiency of Fecal coliforms (indicator organism) in the prepared vermicompost through P.e and E.f was in the 6 log and 7 log (MPN/gm) respectively.