为耦合厌氧氨氧化产生NO2^-的城市污水中试研究

Pilot-scale Study on Producing NO2^-for Anammox With Municipal Wastewater

厌氧氨氧化技术因其节省曝气能耗和有机碳源等突出优势,被认为是迄今为止最经济高效的污水脱氮工艺.然而该技术尚未实现主流城市污水处理的工程化应用,其瓶颈在于厌氧氨氧化所需基质亚硝酸盐(NO2^-)难以稳定获取.目前普遍采用的短程硝化方法在主流条件下难以维持稳定的NO2^-积累.短程反硝化是指将废水中的硝酸盐还原为亚硝酸盐(NO3^-→NO2^-)的过程.短程反硝化技术具有长期稳定的NO2^-积累特性,反应速率快,节省有机碳源,是为厌氧氨氧化菌提供底物NO2^-的新途径.基于此,本研究通过中试规模试验研究验证短程反硝化为厌氧氨氧化提供底物NO2^-的可行性.结果表明,接种的城市污水处理厂剩余污泥具有一定的短程反硝化潜势,以城市污水及其硝化液为进水,通过对进水比例和水力停留时间(hydraulic retention time,HRT)等参数进行调控,成功启动了短程反硝化系统.长期试验结果表明,短程反硝化产生NO2^-的性能逐渐提高,NO3-还原为NO2^-的转化率(nitrate translation rate,NTR)高于75%,且在低温(13.7~16.2℃)条件下仍具有较高的产亚硝酸盐性能,低温阶段平均NTR可达62.3%.本研究为解决城市污水厌氧氨氧化脱氮过程底物NO2^-难以稳定获取的问题提供了思路和方法,对短程反硝化耦合厌氧氨氧化技术在城市污水处理领域的推广应用具有重要意义和研究价值.

Anammox is regarded as the most economical and efficient wastewater nitrogen removal process due to its outstanding advantages of saving aeration energy consumption and organic carbon source.However,it has not yet been applied in the engineering application of the mainstream municipal wastewater treatment,and its bottleneck is the stable acquisition of nitrite(NO2^-).Partial denitrification refers to the process of reducing nitrate to nitrite(NO3-→NO2^-),which is a new approach to provide NO2^-for anammox with the advantages of stable nitrite accumulation and high-rates production.Therefore,the feasibility of partial denitrification to provide NO2^-for anammox has been investigated in a pilot-scale experiment.Results show that partial denitrification can be achieved with excess sludge and municipal wastewater by controlling the influent ratio and HRT when fed with the municipal wastewater and its nitrifying effluent.In the long-term operation,the nitrite production increases and the NO3-to NO2^-translation ratio(NTR)is higher than 75.0%.The partial denitrification can be maintained stably with the condition of low temperature(13.7-16.2℃)and average NTR is 62.3%.This study provides a method and idea to solve the problem of stable acquisition of NO2^-in the process of municipal wastewater nitrogen removal by anammox,which is of great significance and valuable for the application of partial denitrification coupled anammox in municipal wastewater treatment.