低温条件下分流式侧流-AAO工艺污水处理及同步污泥减量效果研究

当前剩余污泥产量巨大及低温条件下运行不稳定是城市污水处理厂活性污泥技术面临的主要挑战和制约.基于此,本文通过向厌氧-缺氧-好氧(AAO)系统中的污泥回流系统引入分流式侧流厌氧系统,以实现强化污水处理和同步污泥减量的目标.结果发现,当侧流分流比例为30%时,分流式侧流-AAO系统能够实现最好的污泥减量效果,污泥累计排放量减少18.43%,污泥表观产率下降19.70%;并且分流式侧流-AAO系统的COD、氨氮和总氮去除效率分别为88.56%、83.12%和71.60%,均略高于AAO系统.同时该条件下,分流式侧流-AAO系统能够在51 d后实现良好的总磷去除效率,并维持出水TP浓度稳定在0.50 mg·L,而AAO系统则需要93 d后才能实现稳定的总磷去除效果.在适当的分流比条件下,分流式侧流厌氧池内能够实现TN的有效去除,可以作为提升水处理系统脱氮能力的潜在手段.

Performance on simultaneously nutrients removal and sludge reduction in AAO combined distributary side-stream anaerobic reactors under low-temperature

Currently, huge amount of waste activated sludge production and unstable operation for nutrients removal under low-temperature condition were the main challenge and constrain to wastewater treatment plants. In order to achieve sludge reduction and enhance nutrients removal simultaneously, a distributary side-stream anaerobic reactor was introduced in the return sludge line. Study indicated that optimal distributary ratio was 30%. Accumulated sludge discharge reduced 18.43% and observed sludge growth rate (Y_obs) reduced 19.70% compared with AAO system. COD, ammonia nitrogen and total nitrogen removal efficiencies of distributary side-stream AAO system were 88.56%, 81.12% and 71.60%, respectively. Organic substance and nitrogen removal were higher than AAO system. Distributary side-stream AAO system achieved efficient total phosphorus removal and maintain total phosphorus concentration in effluent under 0.5 mg·L^-1 faster than AAO system (51 d vs 93 d). Side-stream anaerobic tank achieved efficient TN removal under proper distributary ratio in this study. The result suggested that coupling a side-stream anaerobic tank was a promising approach to upgrading TN removal performance of wastewater treatment processes.