title: Waste activated sludge hydrolysis during ultrasonication: two-step disintegration.
abstract: In order to clearly describe the hydrolysis of waste activated sludge (WAS) during ultrasonication by a 2-step disintegration process, concentrations of ribonucleic acid (RNA) and bound extracellular polymeric substance (EPS) were measured. Apparently, different decreasing patterns of RNA and EPS concentrations during WAS hydrolysis made it possible to distinguish the floc disintegration (FD) and cell lysis (CL). Initially, FD and CL appear to take simultaneously, but the dominant hydrolytic process is shifted from FD to CL after 10 min of ultrasonication. Additional kinetic analysis of WAS hydrolysis was also conducted. A five-fold greater hydrolysis rate constant of FD relative to that of CL was observed, reflecting the different strengths of floc and cells. Therefore, different rates of increased solubilization during WAS hydrolysis appear to account for the initial disintegration of the rather loose part (sludge floc) and the subsequent disintegration of the rigid part (microbial cells).
authors: Department of Civil and Environmental Engineering, KAIST, 373-1 Guseong-Dong, Yuseong-gu, Daejeon, Republic of Korea. sikyung@kaist.ac.kr
authors: Si-Kyung
authors: SK
authors: Cho
authors: Hang-Sik
authors: HS
authors: Shin
authors: Dong-Hoon
authors: DH
authors: Kim
mesh_terms: D057919:Biological Oxygen Demand Analysis; D001704:Biopolymers / Q000032:analysis; D005427:Flocculation; D019220:High-Energy Shock Waves; D006868:Hydrolysis; D007700:Kinetics; D012313:RNA / Q000032:analysis; D012722:Sewage / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D001704:Biopolymers; D012722:Sewage; D012313:RNA