单级和多级A/O工艺中氮的去除效果及N_2O的产生特性  

Nitrogen Removal Effect and Conversion Characteristics of Nitrous Oxide in Single-stage and Multi-stage A/O Processes

作　　者：郭昌梓[1] 张凤燕[1] 刘富宇[1] 朱超[1] 裴立影[1] 

机构地区：[1]陕西科技大学环境科学与工程学院,西安710021

出　　处：《环境科学》2017年第2期647-653,共7页Environmental Science

基　　金：陕西省科技厅自然科学基金项目(2016JM5079);陕西省教育厅专项科研计划项目(14JK1096);陕西科技大学博士科研启动基金项目(BJ13-08)

摘　　要：利用SBR反应器模拟单级和多级A/O工艺,在进水水质、水力停留时间(HRT)、泥龄(SRT)、温度、缺氧好氧时间比(A/O比)均相同的条件下,考察了两种脱氮系统中氮的去除效果及N_2O的释放情况.结果表明,对于与城市污水水质相当的进水水质,单级A/O工艺和多级A/O工艺对COD、氨氮的去除率均在95%以上,二者无明显区别,但是前者对TN的去除效率高于后者,二者的总氮去除率分别为72.1%和52.2%.在氮素的转化过程中,典型周期内(3 h)单级A/O工艺和多级A/O工艺中N_2O的产生量分别为16.95 mg和3.59 mg,其转化率(即N_2O的产量与TN的去除量之比)分别为11.47%和4.11%,且N_2O的产生和释放主要发生在好氧段(硝化阶段),缺氧段(反硝化阶段)基本无N_2O释放.单级A/O工艺比多级A/O工艺更有利于硝化细菌(AOB、NOB)的生长,在相同的运行条件下,两工艺中AOB的优势菌种皆为Nitrosomonas,但前者的相对丰度高于后者;单级A/O工艺中NOB的种类和相对丰度也明显多于多级A/O工艺.在实际运行中采用合适的A/O分区或供氧方式既可以较好地去除污水中氮素污染,又可以减少N_2O的释放对大气造成二次污染.The single-stage A/ O and multi-stage A/ O processes were simulated by sequencing batch reactors （SBRs） with alternate stirring and aeration. The removal efficiency of nitrogen and the release mechanism of N2 O were studied under the identical conditions of influent quality, hydraulic retention time （HRT）, sludge retention time（SRT）, temperature and anoxic/ oxic （A/ O） retention time ratio. Experimental results showed that COD or ammonia-nitrogen removal had no significant difference between the single-stage and the multi-stage A/ O processes for the influent quality equivalent to municipal wastewater. However, TN removal efficiency of the former was better than the later with 72. 1% and 52. 2% , respectively. In the conversion of total nitrogen, during the typical cycle in the single-stage A/ O and multi-stage A/ O processes, the yields of N2 O were 16. 95 mg and 3. 95 mg, respectively. The conversion rate, which is the ratio of N2 O yield and TN removal, was respectively 11. 47% and 4. 11% . N2 O production and emission occurred mainly in aerobic （nitrification） phase while there was little N2 O emission in anoxic （denitrification） phase. Although the dominant species of AOB was both Nitrosomonas in the single-stage A/ O and the multi-stage A/ O processes under the same operating conditions, it was more conducive to the growth of nitrifying bacteria （ AOB, NOB） in the single-stage A/ O process with the greater abundance of Nitrosomonas. Meanwhile, the type and abundance of NOB in the single-stage A/ O process were significantly more than in the multi-stage A/ O process too. Therefore, it is more competitive to deal with the high-strengthening ammonia-nitrogen wastewater in the single-stage A/ O process. In the actual operation of wastewater treatment, using appropriate partitions of A/ O or oxygen-supplying modes can not only result in better nitrogen removal but also decrease the secondary pollution caused by N2 O to the atmosphere.

关 键 词：单级A/O 多级A/O 脱氮 氧化亚氮(N2O) 亚硝酸单胞菌属 

分 类 号：X703.1[环境科学与工程—环境工程]