城市污水部分亚硝化的实现与稳定运行

摘要

在常温(16.4～25.5℃)限氧(溶解氧DO质量浓度为0～0.60 mg/L)条件下,以A/O除磷工艺二级出水为原水,采用中试规模(容积1.14m3)的推流式反应器进行部分亚硝化试验研究.试验结果表明:较低的DO质量浓度(＜0.60mg/L)、沿程交替好氧缺氧的运行模式及较恒定的氨氮污泥去除负荷是实现部分亚硝化的关键因素；通过调整反应器4个格室的曝气量分别为4～8,3～4,0和3～5 L/min,沿程形成好氧、好氧、缺氧、好氧的环境,DO质量浓度分别为0.40～0.60,0.25～0.45,0.05～0.10和0.40～0.60 mg/L,水力停留时间(HRT)为7～9h,污泥回流比为40％～60％,氨氧化率控制在55％左右,出水m(NO2-N)/m(NH4+-N)平均为1.11,部分亚硝化效果稳定,亚硝化率超过95％,达到后续厌氧氨氧化(ANAMMOX)生物滤池进水要求；整个运行阶段污泥沉降性能良好,污泥容积指数(SVI)为60～100 mL/g,未出现污泥膨胀现象.%The effluent of an Anaerobic/Oxic(A/O) process removing phosphorous from municipal wastewater was used as influent to a partial nitritation process of pilot scale plug flow reactor (volume of 1.14 m3) with the conditions of room temperature (16.4-25.5 ℃) and limited oxygen (DO concentration of 0-0.60 mg/L).The experimental result indicates that relatively low DO concentration (＜ 0.60 mg/L),operating mode of alternating aerobic and anoxic as well as the relatively constant sludge removal rate of ammonia are the key factors to achieve partial nitritation.By adjusting the aeration of the four grids in the reactor 4-8,3-4,0,3-5 L/min,DO concentrations controlling in 0.40-0.60,0.25-0.45,0.05-0.10,0.40-0.60 mg/L,forming aerobic,aerobic,anoxic,aerobic environment along the way,hydraulic retention time (HRT)for 7-9 h,the sludge circulation ratio is between 40％-60％.So ammonia oxidation rate is around 55％,the effluent of m(NO2--N)/m(NH4+-N) averaged 1.11,the effect of partial nitritation is stable for the nitrite accumulation rate is over 95％; which meet the requirement of the appropriate influent for the subsequent ANAMMOX biofilter.During the whole operating period,the settleability of sludge is good with volume Index (SVI) being 60-100 mL/g,and sludge bulking does not appear.