交替好氧/缺氧短程硝化反硝化工艺处理低C/N城市污水

Alternating aerobic/anoxic short-cut nitrification and denitrification process for treating low C/N urban sewage

采用好氧/缺氧交替运行模式处理低C/N城市污水,考察了低温环境下启动短程硝化反硝化的可行性,重点研究了好氧池区域Ⅰ、区域Ⅱ、区域Ⅲ溶解氧分布对短程硝化反硝化脱氮效果的影响。结果表明,采用好氧/缺氧交替运行模式,对好氧池溶解氧进行分区优化后,在低温环境下启动短程硝化反硝化具有可行性。在所采用的7种工况中,较为优化的工况是区域Ⅰ、区域Ⅱ、区域Ⅲ,溶解氧分别为0.8~1.2、<0.5、1.2~1.8 mg·L-1,该工况下亚硝态氮累积率稳定在78%以上,出水总氮去除率在73%左右。相比短程硝化反硝化启动前,去除率提高了19.4%,氨氮浓度低于0.60 mg·L-1,出水氮素指标显著优于GB 18918-2002一级A排放标准,出水COD去除率为86.9%~94.9%,出水总磷浓度低于0.15 mg·L-1,可控性仍然较强。对于已启动短程硝化反硝化的A/O工艺处理低C/N城市污水,全年可节约碳源投加资金97×104元左右,节约电费42×104元左右,有效实现了成本与水质的双赢。以上结果可为短程硝化反硝化工艺的工程推广提供参考。

The alternating aerobic/anoxic operation mode was used to treat low C/N urban sewage.The starting up feasibility of the short-cut nitrification and denitrification in low tem perature environment and the effect of dissolved oxygen distribution in aerobic zoneⅠ,ⅡandⅢon the nitrogen removal by the short-cut nitrification and denitrification were studied.The results show that it was feasible to start up the short-cut nitrification and denitrification at low temperature by using the alternating aerobic/anoxic operation mode and partitionoptim izing the dissolved oxygen in aerobic tank.Based on the seven different operating conditions,the dissolved oxygen distributions in the more optimal zonesⅠ,ⅡandⅢwere 0.8〜1.2 mg·L-1,lower than 0.5 m g·L-1,and 1.2〜1.8 mg·L-1,respectively.Under this operating condition,the accum ulation rate of nitrite nitrogen m aintained above 78%,the removal rate of total nitrogen in the effluent was about 73%.Compared with that before the start-up of the short-cut nitrification and denitrification,the removal rate increased by 19.4%,the concentration of ammonia nitrogen was lower than 0.60 mg·L-1 and the nitrogen index of effluent was significantly better than the emission standard of the first level A of GB 18918-2002.The COD removal rate of the effluent was between 86.9%and 94.9%.The total phosphorus concentration of the effluent was lower than 0.15 m g-L"1 with strong controllability.For the low C/N urban sewage treated by using the short-cut nitrification and denitrification A/O process,it can save more than 970000 yuan of carbon source investment fund and 420000 yuan of electricity cost in the whole year,and effectively realize the win-win of cost and water quality.This study provides a case and param eter support for the engineering popularization of the short-cut nitrification and denitrification process.