低温下稳定塘系统对二级出水的处理效果

镇江市征润州污水厂的出水排入长江,为保护长江水环境,需要对其进行深度处理,以使出水水质达到《城镇污水处理厂污染物排放标准》(GB 18918—2002)的一级A标准。采用"好氧塘/兼性塘/生物塘"组合工艺处理该厂出水,考察了系统在低温条件下的脱氮除磷效果。结果表明:该系统能进一步降低二级出水中的TN和TP浓度,对TN、NH3-N、TP的去除率分别为40%、70%和55%,出水TN、NH3-N、TP分别为14、4和0.4 mg/L左右;稳定塘中的硝化作用有利于NH3-N的去除,但厌氧环境的缺乏限制了反硝化作用的进行,使出水TN中NO3--N的比例升高;HRT是稳定塘的重要参数,系统中TN的去除以生物作用为主,可以适当延长HRT以提高对TN的去除率。

Treatment Efficiency of Secondary Effluent by Stabilization Pond System at Low Temperature

The effluent from Zhengrunzhou WWTP in Zhenjiang City is discharged into the Yangtze River.In order to protect the water environment of the Yangtze River,advanced treatment of the effluent was carried out to meet first level A criteria specified in Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant(GB 18918-2002).The stabilization pond system consists of aerobic pond,facultative pond and biological pond.The removal efficiencies of nitrogen and phosphorus in secondary effluent were investigated at low temperature.In the results,the removal rates of TN,NH3-N and TP were 40%,70% and 55% respectively,and the effluent TN,NH3-N and TP concentrations were about 14 mg/L,4 mg/L and 0.4 mg/L respectively.Nitrification in the stabilization pond system was helpful for NH3-N removal,but denitrification was limited by lack of an anaerobic environment,resulting in the increase of NO-3-N ratio in the effluent TN.The HRT was an important parameter for the stabilization pond system.Extending the HRT could improve TN removal solely achieved by biological effect.