低接种量条件下实现厌氧氨氧化快速启动的策略

厌氧氨氧化(Anaerobic ammonia oxidation, anammox)是目前最高效节能的脱氮方式,可以在不加碳源的条件下实现自养高负荷脱氮。然而,厌氧氨氧化菌(Anaerobic ammonia oxidizing bacterial, anAOB)因其生长缓慢,会导致污水处理工艺的启动周期较长。因此,为缩短anammox的启动周期,设置了3种不同污泥接种方式(A：接种500 mg·L^?1 anAOB; B：接种500 mg·L^?1 anAOB+5 000 mg·L^?1反硝化菌;C：接种500 mg·L^?1 anAOB+5 000 mg·L^?1硝化菌)开展anammox启动实验,分析了底物浓度对脱氮效果的影响以及不同接种条件下微生物群落的差异。结果表明,采用向反应器投加500 mg·L^?1 anAOB+5 000 mg·L^?1反硝化菌的接种方式,可以实现anammox的快速启动;启动30 d后,总氮去除效率(nitrogen removal rate, NRR)可达1.41 kg·(m³·d)^?1以上。微生物群落分析结果表明,反应器中主要存在的anAOB为Candaditue Kuenenia;与单独接种anammox污泥相比,接种反硝化污泥和anammox污泥会使Candaditue Kuenenia的相对丰度提高了40.0%,从而使脱氮效率提高了31.2%。底物浓度对anammox过程的影响结果表明,进水${\rm{NO}}_2^{-} $-N质量浓度达到500 mg·L^?1时会导致游离亚硝酸(FNA)浓度升高,而当FNA质量超过0.05 mg·L^?1时,会严重影响anAOB活性,导致反应器出水水质波动;通过降低进水${\rm{NO}}_2^{-} $-N浓度,可以使系统恢复。以上研究结果说明,通过接种反硝化菌和anAOB的方式可实现anammox的快速启动,加速实现anammox工艺在污水处理中大规模应用。

Strategy on fast start-up of anaerobic ammonia oxidation under low inoculation conditions

Anaerobic ammonia oxidation (anammox) was by far the most efficient and energy-saving method of nitrogen removal, which achieved autotrophic and high-load nitrogen removal without adding carbon sources. However, the slow growth characteristic of anaerobic ammonia oxidizing bacteria (anAOB) prolonged the start-up period of wastewater treatment process. Therefore, in order to shorten the start-up cycle of anammox, three sludge inoculation methods (A inoculation with 500 mg·L?1 anAOB; B inoculation with 500 mg·L?1 anAOB+5 000 mg·L?1 denitrifying bacteria; C inoculation with 500 mg·L?1 anAOB+5 000 mg·L?1 nitrifying bacteria) were set up to conduct experiment of anammox. The effect of substrate concentration on the nitrogen removal and the difference of microbial community under different inoculation conditions were analyzed. The results indicated that the method of inoculating low-concentration anammox sludge (500 mg·L?1) and denitrification sludge (5 000 mg·L?1) achieved a rapid start of anammox, and the nitrogen removal rate (NRR) exceeded 1.41 kg·(m3·d)?1 after 30 days. The result of microbial analysis showed that the main anammox bacteria in the reactor was Candidatus Kuenenia. Comparing with the inoculation with anammox sludge alone, the abundance of Candaditue Kuenenia in the inoculation with denitrification sludge and anammox sludge increased by 40.0%, thereby the nitrogen removal efficiency increased by 31.2%. The result of the effect of substrate load showed that when the concentration of ${\rm{NO}}_2^{-} $-N reached 500 mg·L?1, the concentration of free nitrous acid (FNA) increased, FNA concentration exceeding 0.05 mg·L?1 would seriously affect the activity of anAOB and caused the unstable quality of effluent. The system could be restored by reducing the nitrite nitrogen concentration of influent. These results indicated the rapid start of anammox could be achieved by inoculating denitrifying bacteria and anAOB, which will accelerate the large-scale application of the anammox process in sewage treatment.