Evaluation of sludge reduction of three metabolic uncouplers in laboratory-scale anaerobic–anoxic–oxic process

• Published in: Bioresource technology Vol. 221; pp. 31 - 36
• Main Authors: Li, Ping, Li, Hechao, Li, Jin, Guo, Xuesong, Liu, Junxin, Xiao, Benyi
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.12.2016
• Subjects: Anaerobiosis; Chlorophenols - chemistry; Evaluation; Metabolic uncouplers; Salicylanilides - chemistry; Sewage - chemistry; Sludge reduction; Sludge reduction mechanism; Wastewater treatment efficiency; Water Purification; Sludge reduction; Evaluation; Metabolic uncouplers; Wastewater treatment efficiency; Sludge reduction mechanism
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2016.09.019

•Effects of three metabolic uncouplers were evaluated in lab-scale A2O process.•Differences on sludge reduction of three metabolic uncouplers was slight.•Three uncouplers slightly lowered wastewater treatment efficiencies about 1.1–8.7%.•Three uncouplers increased sludge SVI about 69.9–80.6%.•Possible sludge reduction mechanisms of three metabolic uncouplers were different. To evaluate the sludge reduction of three metabolic uncouplers (3,3′,4′,5-tetrachlorosalicylanilide (TCS), 2,4-dichlorophenol (DCP), and tetrakis (hydroxymethyl) phosphonium sulfate (THPS)), we conducted continuous experiments on laboratory-scale anaerobic–anoxic–oxic processes. The three metabolic uncouplers were separately added in each oxic tank of the three systems, and a system without uncoupler addition was used as control. During the 85-day operation, sludge production and observed growth yields decreased to 38.6% and 16.98%, 43.4% and 17.55%, and 39.3% and 17.04% by the addition of TCS, DCP, and THPS, respectively. The addition of metabolic uncouplers slightly reduced the wastewater treatment efficiencies of the system (about 1.1–8.7%) and increased sludge SVIs (about 69.9–80.6%). Meanwhile, the differences among three metabolic uncouplers were little. Besides metabolic uncoupling and maintenance metabolism, which exist in the TCS- and DCP-added systems, lysis–cryptic growth also exists in the THPS-added system.