多点交替进水阶式A2/O工艺氮磷去除途径

为分析CMICAO(多点交替进水阶式A2/O)工艺处理实际生活污水时对氮、磷的去除机理,基于物料衡算方程,计算各反应池内污染物质量浓度,并与实测值进行对比,分析氮、磷的去除途径,提出强化工艺脱氮除磷的方法.结果表明,试验条件下,出水中ρ(TP)、ρ(TN)和ρ(氨氮)分别为(0.41±0.08)、(10.24±0.40)和(2.07±0.30)mg/L.除微生物同化作用外,系统中的氮主要通过好氧硝化、缺氧/厌氧反硝化及SND(同步硝化反硝化)途径去除,阶段一3#反应池、阶段二2#反应池和阶段三1#反应池的SND率分别达到37%、52%和58%左右.磷通过聚磷菌厌氧/缺氧释磷、好氧吸磷和反硝化除磷途径去除,阶段一4#池的反硝化吸磷量达到3 mg/L左右.降低好氧池ρ(DO)和改变缺氧池与厌氧池的进水量比例可强化脱氮除磷效果.

Phosphorus and Nitrogen Removal Pathways in a Commutative Multi-Influent Cascade A2/O Process

As a result of the excessive discharge of nutrients (e.g. nitrogen and phosphorus) into surface water bodies, eutrophication is a global environmental problem and has been identified as a serious threat to ecosystems. A stricter effluent discharge standard was issued to control the release of nitrogen and phosphorus. In order to meet the discharge requirements, a variety of strategies have been proposed to improve the performance of wastewater treatment plants (WWTPs). The commutative multi-influent cascade A²/O (CMICAO) process was developed and studied in Southeast University of China. In order to analyze the removal mechanisms of nitrogen and phosphorus, the CMICAO process was used to treat domestic wastewater. The concentration of pollutants in each reactor was calculated based on the material balance equation. The results obtained were compared with the measured concentration values to analyze removal pathways of nitrogen and phosphorus and further strengthen the nitrogen and phosphorus removal processes. Under laboratory conditions, effluent concentrations of TP, TN and NH₄⁺-N were about (0.41±0.08), (10.24±0.40) and (2.07±0.30)mg/L, respectively. Besides assimilation, the nitrogen was removed through aerobic nitrification, anoxic/anaerobic denitrification and simultaneous nitrification and denitrification (SND). The SND rates in stage one of tank #3, stage two of tank #2 and stage three of tank #1 were about 37%, 52% and 58%, respectively. Phosphorus was released by the phosphate accumulating bacteria under anaerobic/anoxic conditions and taken up excessively under the aerobic condition in order to be removed from the system. The rate of dephosphatation in stage one of the #4 tank was about 3 mg/L. The reduction of dissolved oxygen concentration in the aerobic reactor and the adjustment of feeding ratio in the anoxic and anaerobic reactors were identified to strengthen the nitrogen and phosphorus removal efficiencies. The results provided insights into the removal mechanism and optimized energy consumption and effluent quality.