Evaluation of operational parameters for biodegration of bacterially disintegrated sludge

The present investigation was undertaken to increase the efficiency of sludge solubilization using bacterial pretreatment with a thermophilic protease secreting bacteria, Bacillus licheniformis and deflocculation through ethylene diamine tetra acetic acid (EDTA). About 0.4% of EDTA was used to remove the flocs from the sludge. Then, the deflocculated and bacterially pretreated sludge was subsequently followed by aerobic and anaerobic digestion. In comparison with the control, the aerobic digestion showed 43% increase in the reduction of suspended solids (SS) and 13% increase in the solubilization of chemical oxygen demand. Pretreatment of deflocculated sludge along with anaerobic digestion prompt to 34% of SS and 38% of volatile solids reduction, with an enhancement of 65% biogas production. Pretreatment of deflocculated sludge with B. licheniformis elevates less energy, which was environmentally sound when compared to other pretreatment techniques.