气升式氧化沟污水处理效果的中试研究

在太湖流域某小城镇污水处理厂研究中试气升式氧化沟的污水处理效果,获取了出水主要指标稳定达标的工艺参数.结果表明,出水COD<50mg/L的最大容积负荷为0.88kg/(m3·d).NH4+–N污泥负荷不大于0.06kg /(kg·d)时,出水能达到排放标准要求的5 mg/L.直沟段DO降低到0.6~1.0mg/L后,进出水TN平均浓度分别为30.7,11.3mg/L,并能保证出水TN<15 mg/L稳定运行14d以上.进气量30m3/h时,直段底部最大流速为0.19m/s,中上部流速为0.03m/s,此时沟底没有出现污泥沉降,出水各项指标稳定达标.生产型气升式氧化沟的占地面积将比传统氧化沟至少减少25%.

Wastewater treatment performance of a pilot-scale airlift oxidation ditch

The wastewater treatment performance of a pilot-scale airlift oxidation ditch (AOD) was studied in a wastewater treatment plant near the Taihu Lake. The main process parameters that can satisfy the current discharge standard were obtained. It was possible to achieve a COD effluent concentration <50mg/L at the maximum loading rate of 0.88kg/(m3·d). The ammonium nitrogen concentration of the effluent could be lower than 5 mg/L with a loading rate less than 0.06kg/(kg·d). After the dissolved oxygen in the straight part was maintained between 0.6~1.0mg/L, total nitrogen (TN) concentration in the effluent was less than 15mg/L and kept steadily for over 14 days. The average TN concentrations of the influent and effluent were 30.7mg/L and 11.3mg/L, respectively. When air flow rate was 30m3/h, a velocity of 0.19m/s in the bottom of straight part was sufficient to prevent the settling of activated sludge. Liquid velocity in the top of straight part was only 0.03m/s, but it did not interfere with the removal of organic pollutants. Technical and economic evaluation showed that a large-scale AOD will save at least 25% land area compared with the conventional oxidation ditch.