title: Sludge reduction by direct addition of chlorine dioxide into a sequencing batch reactor under operational mode of repeatedly alternating aeration/non-aeration.
abstract: The effect of direct addition of chlorine dioxide (ClO2) into a repeatedly alternating aeration/non-aeration sequencing batch reactor (SBR) on its sludge reduction and process performance was investigated. The experimental results showed that the sludge reduction efficiency was 32.9% and the observed growth yield (Yobs) of SBR was 0.11 kg VSS (volatile suspended solids) /kg COD (chemical oxygen demand) for 80 days' operation at the optimum ClO2 dosage of 2.0 mg/g TSS (total suspended solids). It was speculated that cell lysis and cryptic growth, uncoupled metabolism and endogenous metabolism were jointly responsible for the sludge reduction in this study. COD, NH3-N, total nitrogen (TN) and total phosphorus (TP) in the effluent increased on average 29.47, 4.44, 1.97 and 0.05 mg/L, respectively. However, the effluent quality still satisfied the first-class B discharge standards for municipal wastewater treatment plants in China. In that case, the sludge maintained fine viability with the specific oxygen uptake rate (SOUR) being 14.47 mg O2/(g VSS·h) and demonstrated good settleability with the sludge volume index (SVI) being 116 mL/g. The extra cost of sludge reduction at the optimum ClO2 dosage was estimated to be 2.24 CNY (or 0.36 dollar)/kg dry sludge.
authors.affiliation: College of Environmental Sciences, Sichuan Agricultural University, 611130 Chengdu, Sichuan, China E-mail: scux_hong@163.com.
authors.forename: Hong
authors.initials: H
authors.lastname: Peng
authors.affiliation: College of Environmental Sciences, Sichuan Agricultural University, 611130 Chengdu, Sichuan, China E-mail: scux_hong@163.com.
authors.forename: Weiyi
authors.initials: W
authors.lastname: Liu
authors.affiliation: College of Environmental Sciences, Sichuan Agricultural University, 611130 Chengdu, Sichuan, China E-mail: scux_hong@163.com.
authors.forename: Yuanmei
authors.initials: Y
authors.lastname: Li
authors.affiliation: College of Environmental Sciences, Sichuan Agricultural University, 611130 Chengdu, Sichuan, China E-mail: scux_hong@163.com.
authors.forename: Hong
authors.initials: H
authors.lastname: Xiao
mesh_terms: D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D002681:China; D017606:Chlorine Compounds; D009584:Nitrogen / Q000032:analysis; D010087:Oxides; D010758:Phosphorus / Q000032:analysis; D012722:Sewage; D018505:Waste Management; D062065:Wastewater / Q000737:chemistry
chemical_list: D017606:Chlorine Compounds; D009584:Nitrogen; D010087:Oxides; D010758:Phosphorus; D012722:Sewage; D062065:Wastewater; C025109:chlorine dioxide