新型城市污水脱氮除磷工艺的试验研究与优化设计

提出了一种改进型A2/O脱氮除磷工艺(MAAO),通过工艺试验和活性污泥2D模型对其进行运行和设计优化.结果表明,系统对COD、TN、NH 4-N和TP的平均去除率分别为85.7%、66.8%、97.35%和78.1%;当COD在300mg/L以上时,脱氮除磷效果均较好,可分别达到70%和90%以上.基于试验结果建立的MMAO工艺数学模型仿真效果良好,可对各单元组合进行优化,校核预测不利工况下的工艺运行效果,实现工艺不同工况下的运行参数优化,较好地实现新工艺的机理性优化设计和运行. MMAO稳定运行出水可达到<城镇污水处理厂污染物排放标准>(GB 18918-2002)一级B标准.由于工艺省去内回流,增加厌氧混合液部分超越提供反硝化碳源,使得运行费用明显降低;系统总停留时间比目前传统的以去除有机污染物为主的生物处理工艺略低,该工艺非常适用于对不具有脱氮除磷功能污水厂的改造.

Novel Phosphorus and Nitrogen Removal Process for Municipal Sewage Treatment: Performance Evaluation and Design Optimization

A novel modified A2/O process (MMAO) was developed for nitrogen and phosphorus removal of municipal sewage. Bench-scale study was conducted to evaluate the performance of the MMAO process treating practical municipal sewage at normal temperature. Activated sludge model (ASM2D) was used to simulate the MMAO process and optimize its design and operation. It was found that the average treatment efficiency of COD, TN, NH4+-N and TP achieved by MMAO were up to 85.7%, 66.8%, 97.35% and 78.1%, respectively. When influent COD concentration of the system was more than 300 mg/L, a better nitrogen and phosphorus removal efficiency of 70% and 90% were achieved. After being calibrated and validated by the experimental results, the activated sludge model of MMAO could simulate the biological reactions occurred in the systems excellently. Optimization design and operational parameters could be accomplished by the mechanical activated sludge modeling. Furthermore, the model could also evaluate the process performance under peak load and low temperature and presented a whole scheme toward the unit combination and operation control. The effluent quality of MMAO process under stable operating could reach the first (B) standard of Municipal Sewage Treatment Plant Pollutants Discharge Standards (GB 18918-2002). The effluent of anaerobic unit was pumped directly into the anoxic unit to supply carbon source for denitrification instead of internal recirculation of mixture liquid, which would save operation cost significantly. The total hydraulic retention time of MMAO was lower than traditional biological organic removal system, so it was very suitable for the improvement of existing plant.