污水处理厂尾水导流工程中氮元素的变化规律

Change of Nitrogen Elements in Tail Water Diversion Project of Wastewater Treatment Plant

宿迁市污水处理厂的导流工程是保障南水北调东线工程调水水质的重要举措,但传输过程中污水水质的变化规律尚未明确,其对最终出水水质的影响亦未可知。因此,调查了近3年来8座污水处理厂出水水质的变化,在明确其存在典型水质问题的基础上,利用试验模拟污水输配过程,探究混合时间、初始浓度、温度、初始生化比等因素对输送过程中总氮、硝态氮、氨氮的影响,并确定其对总排口水质的影响。结果表明,混合时间、初始浓度、初始生化比对出水中的氮污染物浓度没有显著影响;温度对氨氮浓度的变化影响显著,温度升高,氨氮浓度呈现下降的趋势。高通量测序结果表明,随着输送距离的增加,导流管壁附着微生物的多样性增加,功能菌属的生物降解作用有利于氮的转化去除。

The tail water diversion project of wastewater treatment plant in Suqian is an important measure to ensure the water quality of the east route of South-to-North Water Transfer Project.However,the change rule of water quality in the transfer process is not clear,and its influence on the final effluent quality is also unknown.The change of effluent quality of eight wastewater treatment plants in the past three years were investigated.On the basis of defining the typical water quality problems,the wastewater diversion and transportation process was simulated by laboratory experiments.Then,effects of mixing time,initial concentration,temperature and initial biochemical ratio on total nitrogen,nitrate nitrogen and ammonia nitrogen in the transportation process were explored,and influence of nitrogen variation on water quality of the main outlet was finally determined.Mixing time,initial concentration and initial biochemical ratio had no significant effect on nitrogen concentration in effluent.Temperature had a significant influence on the change of ammonia nitrogen concentration,and the concentration of ammonia nitrogen decreased with the increase of temperature.The microbial community composition was analyzed by high-throughput sequencing.The diversity of wall-attached microorganisms increased with the transportation distance,and biodegradation of the functional bacteria was beneficial to the transformation and removal of nitrogen.