通过对某污水处理厂循环活性污泥法工艺(cyclic activated sludge technology，CAST)中选择池、缺氧池和好氧池中氮组分和污泥浓度进行测定，结合污泥活性、同步硝化-反硝化(simultaneous nitrification and denitrification，SND)速率及饱食-饥饿(feast-famine)批次实验，评价该处理工艺的脱氮性能。结果表明，好氧池内同步硝化-反硝化和沉淀过程中的内源反硝化(endogenous denitrification，ED)脱氮对总氮去除的贡献占据主导，分别为(35。50±4。15)％和(62。86±4。13)％，而缺氧池反硝化(DEN)脱氮贡献仅为(1。64±0。05)％;溶解氧(dissolved oxygen，DO)浓度对CAST工艺脱氮性能有极大影响，控制好氧池中DO浓度为1～1。5 mg·L-1时可获得最佳脱氮效果，CAST工艺的TN去除率可达84。51％;饱食-饥饿批次实验证明，饥饿时长为36 h时对乙酸(HAc)的吸收能力最强，可达每1 g VSS消耗0。173 g HAc，依此可推算出CAST工艺的最佳回流比为45％。
Evaluation of nitrogen removal performance of the CAST process in a wastewater treatment plant
The nitrogen removal performance of CAST process in a wastewater treatment was evaluated by measuring the nitrogen components and suspended solids in the selective,anoxic and aerobic tanks,combined with the simultaneous nitrification and denitrification(SND)rate and feast-famine batch tests.The results showed that the contribution to total nitrogen(TN)removal through SND in aerobic tank and endogenous denitrification at sedimentation stage were dominated,which were(35.50±4.15)％and(62.86±4.13)％,respectively,while the denitrification in anoxic tank only accounted for(1.64±0.05)％.The Dissolved oxygen(DO)concentration had a great influence on the nitrogen removal performance of CAST process.The best nitrogen removal effect happened when the DO concentration in aerobic pool was controlled at 1～1.5 mg·L-1,and the TN removal rate of CAST process could reach 84.51％.The Feast-Famine batch tests proved that the maximum absorption of HAc occurred at the famine duration of 36 h,being up to 0.173 g HAc per 1 g VSS consumption.Based on this result,the optimal reflux ratio could be estimated to be 45％.
CASTnitrogen removalsimultaneous nitrification and denitrificationendogenous denitrificationfeast-famine
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