title: Impact of alkaline-hydrolyzed biosolids (Lystek) addition on the anaerobic digestibility of TWAS in lab--and full-scale anaerobic digesters.
abstract: The effect of different Lystek biosolids doses on the anaerobic digestability of thickened waste activated sludge (TWAS) was evaluated in a lab- and full-scale anaerobic digester. The overall findings of this study emphasize the beneficial impact of Lystek addition to the lab- and full-scale anaerobic digesters in terms of enhanced biogas production and increased volatile suspended solids reduction (VSSR) efficiency. Lystek added at 4% by volume to TWAS increased the methane yield from 0.22 to 0.26 L CH4/g VSSadded at an solids retention time (SRT) of 10 days, and from 0.27 to 0.29 L CH4/g VSS(added) at an SRT of 15 days. Furthermore, the VSSRs of 37% and 47% were observed for the TWAS, and the TWAS with 4% Lystek, while at an SRT of 15 days, the observed VSSR were 49% and 58%, respectively. The lab-scale study showed that the influence of Lystek addition on methane yield and solids destruction efficiencies was more pronounced at the shorter SRT, 20% enhancement (SRT of 10d) vs. 9% enhancement (SRT of 15 d) for methane yield, and 27% (SRT of 10d) vs. 22% (SRT of 15 d) for VSS destruction efficiency improvement. Furthermore, addition of 4% of Lystek to the feed of the full-scale anaerobic digester at St. Marys wastewater treatment plant (WWTP) resulted in a 50% increase in the average specific methanogenic activity and 23% increase in methane yield of the biochemical methane potential tests after eight months. The results showed that Lystek degradation kinetics were 40% faster than the TWAS, as reflected by first order kinetic coefficients of 0.053 d(-1) and 0.073 d(-1) for TWAS and Lystek at an SRT of 10 days.
authors.affiliation: University of Waterloo, Waterloo, ON, Canada.
authors.forename: Elsayed
authors.initials: E
authors.lastname: Elbeshbishy
authors.affiliation: Western University, London, ON, Canada.
authors.forename: Saad
authors.initials: S
authors.lastname: Aldin
authors.affiliation: Western University, London, ON, Canada.
authors.forename: George
authors.initials: G
authors.lastname: Nakhla
authors.affiliation: Lystek International Inc., Cambridge, ON, Canada.
authors.forename: Ajay
authors.initials: A
authors.lastname: Singh
authors.affiliation: Lystek International Inc., Cambridge, ON, Canada.
authors.forename: Bill
authors.initials: B
authors.lastname: Mullin
mesh_terms: D000693:Anaerobiosis; D056804:Biofuels / Q000032:analysis; D019149:Bioreactors; D008697:Methane / Q000096:biosynthesis; D012722:Sewage / Q000032:analysis*; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000032:analysis*
chemical_list: D056804:Biofuels; D008697:Methane; D012722:Sewage; D062065:Wastewater
keywords: Anaerobic digestion; BMP; Full-scale; Lystek; SMA; TWAS