A study on the impact of sludge water on biological phosphorus removal process of the municipal wastewater treatment plant and its treatment process

Abstract

At present, the research focus for sludge water was mainly concentrated on nitrogen removal, the study on the impact of sludge water with high concentration suspended solid (SS) and total phosphorus (TP) on phosphorus removal system is rare, and there is a gap in the research of processing technology for this type of sludge water The impact of sludge water on phosphorus removal process was investigated by field investigation and test analysis on an A²O process of a typical municipal wastewater treatment plant in Xi’an. Based on the sludge water quality characteristics of high concentration SS and TP, the study on coagulation dephosphorization technology was carried out. Through the sludge water coagulation mechanism analysis, the operating conditions of coagulation were optimized. The results of the study showed the appropriate polyaluminium chloride dosage was from 100 to 200 mg/L and the TP concentration after coagulation was about 14–11.6 mg/L. The coagulation process can effectively alleviate impact of sludge water on the system phosphorus removal process, and guarantee the outflow stable up-to-first grade A standards.

Keywords:

• Sludge water
• Biological phosphorus removal process
• Municipal wastewater treatment plant
• Coagulation dephosphorization process

Acknowledgements

This study was supported by the National Program of Water Pollution Control (Grant No. 2011ZX07302-001), Science and Technology Innovation Project of Shaanxi Province (Grant No. 2011KTZB03-03-03) and Innovative Research Team of Shaanxi Province of China (Grant No. IRT 2013KCT-13).