MBR enhanced nitrogen and phosphorus removal technology

Thread Content

【Technology Name】MBR Enhanced Nitrogen and Phosphorus Removal Technology 【Technology Description】Targeting wastewater with low carbon sources, this technology overcomes the issue of the high carbon source requirements for nitrogen and phosphorus removal by organically combining membrane separation and biological treatment units, without the need to add external carbon sources. 【Application Scope】Nitrogen and phosphorus removal from low-carbon source wastewater 【Subject Category】Urban areas 【Technical Development Stage】Widespread application 【Key Technical Indicators and Parameters】The treated effluent meets the requirements of Standard for Discharge of Pollutants from Urban Sewage Treatment Plants, Grade A1, as well as the Standard for Quality of Water Used in Landscape Applications from Recycled Urban Sewage; endogenous denitrification contributes 20–30% to nitrogen removal. 【Basic Principle】Make full use of the MBR’s ability to retain high-concentration sludge, so as to keep high-concentration nitrifying bacteria within the reactor and improve the nitrification effect ； By utilizing internal carbon sources and through appropriate process design, endogenous denitrification is enhanced to improve the total nitrogen removal rate ； Leverage the high-efficiency retention capability of the membrane to enhance the retention of colloidal phosphorus ； Based on the characteristics of the MBR process, chemical phosphorus removal agents and methods are optimized to compensate for the limitations of biological phosphorus removal and enhance the phosphorus removal efficiency. 【Process Flow】The process flow includes anaerobic – pre-anoxic – aerobic – post-anoxic – membrane tank. The wastewater first enters the anaerobic tank, where anaerobic phosphorus release occurs ； After that, it enters the pre-anoxic tank; the return flow from the aerobic tank brings in a large amount of *AO acid salts. Denitrifying bacteria use the carbon sources present in the water to carry out denitrification and remove nitrogen, while some denitrifying polyphosphate-accumulating bacteria utilize intracellular PHA for denitrification and phosphorus removal ； It then enters the aerobic tank, where ammonia nitrogen in the influent water is removed through nitrification, and polyphosphate-accumulating bacteria remove dissolved phosphorus by absorbing it ； After that, the water enters the anoxic tank; since the carbon source has been almost completely depleted in the aerobic tank, the main function of this stage is to utilize the high sludge concentration to promote endogenous denitrification, thereby achieving thorough removal of total nitrogen ； Finally, the water enters the membrane tank; its high sludge concentration, high dissolved oxygen level, and strong separation capacity further ensure the quality of the effluent water. 【Key Technology】A MBR nitrogen and phosphorus removal process based on enhanced endogenous denitrification, tailored to the characteristics of local wastewater, has been developed. This approach addresses the challenge of achieving satisfactory nitrogen and phosphorus concentrations in the effluent for wastewater with a low carbon/nitrogen ratio in the Taihu Lake region, and features strong resistance to shock loads as well as stable effluent quality. 【Technical Source and Intellectual Property Overview】Developed independently. 【Application Cases】Applying entity: Wuxi Shuofang Sewage Treatment Plant. Introduction to the actual application case: A demonstration project with a treatment capacity of 20,000 m3/day was established at the Wuxi Shuofang Sewage Treatment Plant. The project came online in November 2009. Operation monitoring data show that the effluent quality parameters such as COD, ammonia nitrogen, total nitrogen, and total phosphorus meet the requirements of Standard Grade A1 for pollutant discharge from urban sewage treatment plants as well as the standards for water quality used in landscape applications in urban wastewater reuse; the average energy consumption per ton is 0.65 kWh/m3.