title: Enzyme treatment to reduce solids and improve settling of sewage sludge.
abstract: The effect of microbial enzymes in reducing the disposable solid content of sludge was investigated. A mixture of industrial cellulase, protease, and lipase, in equal proportion by weight, reduced total suspended solids (TSS) by 30-50% and improved settling of solids. An increase in solid reduction was observed with increasing enzyme concentration. The effect of combinations of enzyme treatments indicated that two-enzyme combinations of protease and cellulase produced better solid reduction than individual enzymes and that lipase further augmented this effect. Among the individual enzymes, protease produced a more settleable sludge as compared to cellulase and lipase. Adjustment of the pH of the enzymatically treated sludge to the acidic range (pH 2-4) further improved solid reduction, and adjustment to the alkaline range (pH 10-12) improved settleability.
authors.affiliation: Department of Biology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.
authors.forename: N
authors.initials: N
authors.lastname: Parmar
authors.forename: A
authors.initials: A
authors.lastname: Singh
authors.forename: O P
authors.initials: OP
authors.lastname: Ward
mesh_terms: D001673:Biodegradation, Environmental; D002480:Cellulase / Q000378:metabolism*; D010450:Endopeptidases / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008049:Lipase / Q000378:metabolism*; D010316:Particle Size; D011312:Pressure; D012037:Refuse Disposal / Q000379:methods*; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology*; D014865:Waste Disposal, Fluid / Q000379:methods
chemical_list: D012722:Sewage; D008049:Lipase; D002480:Cellulase; D010450:Endopeptidases