Resource Reuse of Waste-Activated Sludge as Raw Material of Microbial Flocculant Preparation: Methods and Comparison
Zhiqiang Zhang1,2, Jiao Zhang3, Siqing Xia2
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1Key Laboratory of Yangtze River Water Environment, Ministry of Education,
College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
2State Key Laboratory of Pollution Control and Resource Reuse,
College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
3School of Civil Engineering and Transportation, Shanghai Technical College of Urban Management,
Shanghai 200432, China
Pol. J. Environ. Stud. 2013;22(3):951–956
Resource reuse of waste-activated sludge (WAS) from a municipal wastewater treatment plant (WWTP) was introduced as raw material of microbial flocculant (MBF) preparation. With WAS samples of three concentrations, MBF preparation by various methods – including cation exchange resin (CER), CER-ultrasonication, CER-ultrasonication-CER, ultrasonication, ultrasonication-CER, and ultrasonication-CER-ultrasonication methods – were comparatively investigated. According to the results of chemical compositions, concentrations, and flocculating activities of the prepared MBFs, the compound methods excelled the sole methods, and the CER-ultrasonication method was the best. Major compositions of the prepared MBFs contained polysaccharides, proteins, and nucleic acids. Improving sludge concentration was beneficial to extract MBF in high concentrations using the above methods. Appropriate MBF mass dosage was crucial its flocculating activity because less or more dosage would deteriorate the flocculation. The mechanism analysis indicated that CER treatment could provide a good pretreatment for ultrasonication, but became useless when it was set after ultrasonication.