title: Optimized production of a novel bioflocculant M-C11 by Klebsiella sp. and its application in sludge dewatering.
abstract: The optimized production of a novel bioflocculant M-C11 produced by Klebsiella sp. and its application in sludge dewatering were investigated. The optimal medium carbon source, nitrogen source, metal ion, initial pH and culture temperature for the bioflocculant production were glucose, NaNO3, MgSO4, and pH7.0 and 25°C, respectively. A compositional analysis indicated that the purified M-C11 consisted of 91.2% sugar, 4.6% protein and 3.9% nucleic acids (m/m). A Fourier transform infrared spectrum confirmed the presence of carboxyl, hydroxyl, methoxyl and amino groups. The microbial flocculant exhibited excellent pH and thermal stability in a kaolin suspension over a pH range of 4.0 to 8.0 and a temperature range of 20 to 60°C. The optimum bioflocculating activity was observed as 92.37% for 2.56mL M-C11 and 0.37g/L CaCl2 dosages using response surface methodology. The sludge resistance in filtration (SRF) decreased from 11.6×10(12) to 4.7×10(12)m/kg, which indicated that the sludge dewaterability was remarkably enhanced by the bioflocculant conditioning. The sludge dewatering performance conditioned by M-C11 was more efficient than that of inorganic flocculating reagents, such as aluminum sulfate and polymeric aluminum chloride. The bioflocculant has advantages over traditional sludge conditioners due to its lower cost, benign biodegradability and negligible secondary pollution. In addition, the bioflocculant was favorably adapted to the specific sludge pH and salinity.
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Beijing Normal University, Beijing 100875, China.. Electronic address: liujw123@gmail.com.
authors.forename: Jiewei
authors.initials: J
authors.lastname: Liu
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Beijing Normal University, Beijing 100875, China.. Electronic address: jwma@bnu.edu.cn.
authors.forename: Junwei
authors.initials: J
authors.lastname: Ma
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Beijing Normal University, Beijing 100875, China.
authors.forename: Yanzhong
authors.initials: Y
authors.lastname: Liu
authors.affiliation: State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Beijing Normal University, Beijing 100875, China.
authors.forename: Ya
authors.initials: Y
authors.lastname: Yang
authors.affiliation: School of Environment, Tsinghua University, Beijing 100084, China.
authors.forename: Dongbei
authors.initials: D
authors.lastname: Yue
authors.affiliation: School of Environment, Tsinghua University, Beijing 100084, China.
authors.forename: Hongtao
authors.initials: H
authors.lastname: Wang
mesh_terms: D005427:Flocculation; D006863:Hydrogen-Ion Concentration; D007709:Klebsiella / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D012722:Sewage; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D014867:Water
chemical_list: D012722:Sewage; D014867:Water
keywords: Bioflocculant; Klebsiella sp.; Optimized production; Response surface methodology; Sludge dewatering