title: Effect of low solids retention time and focused pulsed pre-treatment on anaerobic digestion of waste activated sludge.
abstract: The interacting effects of Focused Pulsed (FP) treatment and solids retention time (SRT) were evaluated in laboratory-scale digesters operated at SRTs of 2-20 days. Anaerobic digestion and methanogenesis of waste activated sludge (WAS) were stable for SRT ≥ 5 days, but the effluent soluble organic compounds increased significantly for SRT=2 days due to a combination of faster hydrolysis kinetics and washout of methanogens. FP treatment increased the CH(4) production rate and TCOD removal efficiency by up to 33% and 18%, respectively, at a SRT of 20 days. These effects were the result of an increase in the hydrolysis rate, since the concentrations of soluble components remained low for SRT ≥ 5 days. Alternately, FP pre-treatment of WAS allowed the same conversion of TCOD to CH(4) with a smaller SRT and digester size: e.g., 40% size savings with a CH(4) conversion of 0.23 g CH(4)-COD/g COD(in).
authors.affiliation: Center for Environmental Biotechnology, The Biodesign Institute at Arizona State University, Tempe, AZ 85287-5701, USA. ilsu.lee@asu.edu
authors.forename: Il-Su
authors.initials: IS
authors.lastname: Lee
authors.forename: Bruce E
authors.initials: BE
authors.lastname: Rittmann
mesh_terms: D001421:Bacteria, Anaerobic / Q000378:metabolism*; D006868:Hydrolysis; D007220:Industrial Waste / Q000517:prevention & control; D008657:Metabolic Clearance Rate; D008697:Methane / Q000378:metabolism*; D009930:Organic Chemicals / Q000378:metabolism*; D012722:Sewage / Q000382:microbiology*
chemical_list: D007220:Industrial Waste; D009930:Organic Chemicals; D012722:Sewage; D008697:Methane