title: Thermo-alkaline pretreatment of waste activated sludge at low-temperatures: effects on sludge disintegration, methane production, and methanogen community structure.
abstract: Low-temperature thermo-alkaline pretreatment of waste activated sludge (WAS) was studied, within the region of 0-0.2 M NaOH and 60-90°C, for the effects of NaOH concentration and temperature on sludge degradability in anaerobic digestion (AD). Significant disintegration of sludge solids (up to 75.6%) and an increase in methane production (up to 70.6%) were observed in the pretreatment trials. Two quadratic models were successfully generated by response surface analysis (R(2)>0.9, p<0.05) to approximate how the degree of sludge disintegration (SD) and methane production (MP) respond to changes in the pretreatment conditions. The maximum responses of SD (77.8%) and MP (73.9% increase over the control) were shown at [0.16 M NaOH, 90°C] and [0.10 M NaOH, 73.7°C], respectively. NaOH addition showed a significant influence on the evolution of methanogen community structure during AD, whereas temperature did not. Aceticlastic Methanosaeta and Methanosarcina speceies were likely the major methanogens.
authors.affiliation: School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulju-gun, Ulsan 689-798, Republic of Korea.
authors.forename: Jaai
authors.initials: J
authors.lastname: Kim
authors.forename: Youngseob
authors.initials: Y
authors.lastname: Yu
authors.forename: Changsoo
authors.initials: C
authors.lastname: Lee
mesh_terms: D000468:Alkalies / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects / Q000254:growth & development*; D001483:Base Sequence; D001673:Biodegradation, Environmental / Q000187:drug effects; D003080:Cold Temperature; D058645:Denaturing Gradient Gel Electrophoresis; D008697:Methane / Q000096:biosynthesis*; D008962:Models, Theoretical; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012722:Sewage / Q000737:chemistry*; D012972:Sodium Hydroxide / Q000494:pharmacology; D014865:Waste Disposal, Fluid
chemical_list: D000468:Alkalies; D012336:RNA, Ribosomal, 16S; D012722:Sewage; D012972:Sodium Hydroxide; D008697:Methane
keywords: Anaerobic digestion; Methanogen community structure; Response surface analysis; Thermo-alkaline pretreatment; Waste activated sludge