为了解决垃圾渗滤液与城市污水合并处理氮难以稳定达标排放的问题,采用倒置A2/O法合并处理混合污水脱氮。结果表明,水力停留时间是脱氮效果的限制因素,试验条件下水力停留时间至少应保证9h。好氧池溶解氧浓度增加对总氮去除不利;在60%~100%的范围内提高污泥回流比对有机物去除和反硝化有利;混合液回流比在100%-200%范围内增加对反硝化有一定促进作用。在水温25-30℃、泥龄20d、MLSS3000-3500mg/L、HRT11h、DO3mg/L、R80%、r200%时,有机物和脱氮效果同步达到最优,且出水浓度均可稳定地达到《城镇污水处理厂污染物排放标准》(GB18918—2002)一级A标准。
In order to solve the problem that the consolidated treatment of leachate and municipal wastewater is difficult to reach the standard of nitrogen, the reversed A^2/O process is used to removal nitrogen in the experiment. The results show that HRT (hydraulic retention time) is the key factor for nitrogen removal efficiency. HRT should be long at least 9 hours under the test conditions. The increase of dissolved oxygen of the aerobic basin is hurt to the total nitrogen removal. At the range of 60% to 100%, the improvement of the sludge return ratio could get better organic and denitrification removal treatment effect. At the range of 100% to 200%, the improvement of the mixed-liquor return ratio could get better denitrification removal treatment effect. Under the conditions of water temperature with 25-30℃, SRT with 20 d, MLSS with 3 000-3 500 mg/L, HRT with 11h, DO with 3.0 mg/L, R with 80 % and r with 200 %, the effect of organic and nitrogen removal achieve the optimal synchronization simultaneously and the effluent concentration could steadily reached the A-level standard according to the standard of Discharge standard of pollutants for municipal wastewater treatment plant.