Effect of enzyme secreting bacterial pretreatment on enhancement of aerobic digestion potential of waste activated sludge interceded through EDTA

• Published in: Bioresource technology 2013-12, Vol.150, p.210-219
• Main Authors: Kavitha, S., Adish Kumar, S., Yogalakshmi, K.N., Kaliappan, S., Rajesh Banu, J.
• Format: Article
• Language: English
• Subjects: Activated sludge; Aerobic digestion; Aerobiosis; Applied sciences; Bacteria; Bacteria - drug effects; Bacteria - enzymology; Bacteria - growth & development; Bacterial pretreatment; Biodegradation, Environmental - drug effects; Biological and medical sciences; Biological Oxygen Demand Analysis; Biological treatment of sewage sludges and wastes; Biopolymers - pharmacology; Biotechnology; Edetic Acid - pharmacology; EDTA; Environment and pollution; Enzymes; Enzymes - secretion; EPS; Ethylene diamine tetra acetic acid; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Hydrogen-Ion Concentration - drug effects; Industrial applications and implications. Economical aspects; Kinetics; Pollution; Pretreatment; Response surface methodology; Sewage - microbiology; Sludge; Solubility; Suspended solid reduction; Temperature; Time Factors; Wastes
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2013.10.021

•Removal of EPS with 0.2g/g SS of EDTA enhanced the bacterial pretreatment.•Kinetic parameters of deflocculated sludge reveal efficient sludge reduction.•Solubilization in deflocculated sludge was 11% higher than the control.•SS reduction in “E” reactor which contains pretreated sludge was 48.5%. In this study, the effect of Ethylene diamine tetra acetic acid (EDTA) on Extracellular polymeric substance (EPS) removal tailed with bacterial enzymatic pretreatment on aerobic digestion of activated sludge was studied. In order to enhance the accessibility of sludge to the enzyme secreting bacteria; the extracellular polymeric substances were removed using EDTA. EDTA efficiently removed the EPS with limited cell lysis and enhanced the sludge enzyme activity at its lower concentration of 0.2g/g SS. The sludge was then subjected to bacterial pretreatment to enhance the aerobic digestion. In aerobic digestion the best results in terms of Suspended solids (SS) reduction (48.5%) and COD (Chemical oxygen demand) solubilization (47.3%) was obtained in experimental reactor than in control. These results imply that aerobic digestion can be enhanced efficiently through bacterial pretreatment of EPS removed sludge.