无回流生物滤床净化槽脱氮效果的研究

构建一种脱氮的无回流生物滤床家庭生活污水处理一体化净化槽,研究其处理效果;改变各区内的曝气形式,形成A/O/A/O的脱氮工艺,通过测定各区COD、NH+4-N、NO-3-N和TN的浓度变化,考察其处理效果。结果表明:随着净化槽各区生物滤床的加入,反应器抗冲击性增强,处理效果明显提高。但A/O/A/O系统中第二级厌氧过程因碳源不足,脱氮效果不佳,改用分段进水后,净化槽不仅运行稳定,而且取得了很好的处理效果,出水COD平均浓度12.3 mg·L~(-1),NH+4-N平均浓度2.7 mg·L~(-1),TN平均浓度13.0mg·L~(-1),均达到国标(GB 18918—2002)一级A标准。A/O/A/O生物滤床新型净化槽不仅在结构上形成一体化,而且由于生物滤床的使用,不需要污泥回流,节省能耗,通过分段进水可以实现过程脱氮。

Study on nitrogen removal effect of non-circumfluence bio-filter purifying tank

A non-circumfluence multi-functional integrated bio-filter purifying tank was developed to study the removal performance of nitrogen and chemical oxygen demand(COD) in rural domestic sewage. The influence of support media on pollutant biodegradation was investigated by adding support media in each zone in a stepwise manner. Subsequently, the aeration condition was changed to anaerobic/oxide/anoxic/oxide(A/O/A/O) mode and variations of COD, NH₄⁺-N, NO₃^--N, and total nitrogen(TN) concentrations in each zone were detected. Stable effluent quality and good resistance to shock-loading were achieved in the purifying tank when the support media were employed. In the A/O/A/O system, the denitrification efficiency was unsatisfactory because of the lack of carbon source in the second anoxic stage. However, when the step-feed strategy was adopted, the treating performance of the purifying tank became stable and afforded highly efficient nitrogen removal. Specifically, the average effluent concentration of COD, NH₄⁺-N, and TN reached 12.3, 2.7 mg·L^-1 and 13.0 mg·L^-1, respectively, which satisfies the national primary A of discharge standard(GB 18918-2002). Overall, the purifying tank with the A/O/A/O operation mode not only performed as a compact reactor to remove nitrogen by step-feed, but also avoided the recirculation of sludge by employing the bio-filter and saved energy costs.