一种基于脱氮和除磷分开的强化污染物去除组合工艺中试研究

针对北京等严重缺水地区提高污水综合排放标准,用于地表水和地下水补充水的需求,以强化COD、N和P去除为目的,研发了N和P不同单元处理的缺氧立体循环氧化沟单元/好氧立体循环氧化沟单元/除磷过滤器单元组合工艺,通过中试实验研究了该工艺的去除效果,并优化了该工艺水力停留时间(HRT)和溶解氧(DO)参数。结果表明,当缺氧和好氧立体循环氧化沟单元的HRT 和DO分别为12 h、DO 0.5 mg/L和6 h、2.0 mg/L,除磷过滤器滤速6~8 m/h时,该工艺的平均出水浓度COD 25 mg/L,TN 11 mg/L,NH4+-N 1.2 mg/L,TP 0.15 mg/L,平均去除率分别为88%、57%、94%和96%。其中缺氧立体循环氧化沟单元COD、NH4+-N和TN平均去除率为70%、80%和57%,好氧立体循环氧化沟单元进一步去除COD和NH4+-N(去除率为18%和14%);经缺氧、好氧氧化沟处理去除50%左右的TP,除磷单元吸附作用去除46%的TP。经过该组合工艺处理,COD、N和P都能达到北京市2013年出台的地方污水排放新标准一级B排放要求。

Pilot study on a combined process based on separation of nitrogen and phosphorus removal for enhancing pollutant removal

In order to meet the increased sewage discharge standards for some regions of China (such as Beijing) and the supplement surface and groundwater, a combined process based on separation of nitrogen and phosphorus removal for enhancing pollutant removal was developed. The combined process includes an anoxic oxidation ditch process with vertical circulation (ODVC), an aerobic ODVC and a phosphorus filter. The combined process was developed for enhancing removal of chemical oxygen demand (COD), nitrogen (N), and phosphorous (P), in which N and P were removed in different units. Pilot test was carried out to study the pollutant removals of the combined process and its optimization based on hydraulic retention time (HRT) and dissolved oxygen (DO). The results showed that the average effluent qualities of the combined process were COD of 25 mg/L, total nitrogen (TN) of 11 mg/L, ammonium nitrogen (NH4+-N) of 1.2 mg/L, and total phosphorous (TP) of 0.15 mg/L, respectively, when the HRT and DO of anoxic ODVC and aerobic ODVC were 12 h at 0.5 mg/L and 6 h at 2.0 mg/L, and the filtration velocity of the P filter was 6 to 8 m/h. The average removal rates of COD, TN, NH4+-N, and TP reached 88%, 57%, 94%, and 96%, respectively. Approximately 70% of COD, 80% of NH4+-N, and 57% of TN were removed in the anoxic ODVC unit. The remaining COD and NH4+-N (with average removals of 18% and 14%) were further removed in the aerobic ODVC unit. About 50% of TP was removed in the first two units and the remainder was removed in the P filter unit. The average effluent of the combined process could reach the class 1-type B of the new comprehensive sewage discharge standard of Beijing implemented in 2013.