ABR-MBR工艺处理生活污水实现短程硝化

Realization of Shortcut Nitrification in the ABR-MBR Process Treating Domestic Wastewater

采用ABR-MBR耦合工艺对MBR反应器中实现短程硝化的运行控制条件进行了研究,并为后续研究系统的反硝化除磷性能打下基础.ABR-MBR耦合工艺在不同条件下的运行研究结果表明,在ABR反应器的水力停留时间(hydraulic retention time,HRT)6 h,污泥回流比100%,硝化液回流比300%,温度30℃±2℃的条件下,通过控制好氧区溶解氧浓度(DO从0.5~1.0 mg·L^(-1)降为0.3~0.7 mg·L^(-1))以及改变MBR反应器有效容积以控制其HRT,最终在MBR反应器HRT从3 h逐步延长至5 h时短程硝化遭到破坏,亚硝酸盐积累率(nitrite accumulation rate,NAR)从60%急剧下降至15%.短程硝化影响因素的分析表明:pH值、游离氨(free ammonia,FA)和游离亚硝酸(free nitrous acid,FNA)对本试验实现短程硝化无显著影响,维持低DO浓度(0.3~0.7 mg·L^(-1))并逐步缩短HRT是本试验实现短程硝化的关键控制因素,温度和污泥停留时间(sludge retention time,SRT)可作为辅助因素与之共同调控.短程硝化期间,系统获得了高效且稳定的COD和NH_4^+-N去除效果,平均出水浓度分别低于50 mg·L^(-1)和2 mg·L^(-1),去除率均在90%以上,TN平均去除率高达72%.

The operational control conditions for realizing shortcut nitrification in the membrane bioreactor （ MBR） process was investigated in a lab-scale anaerobic baffled reactor （ABR）-MBR combined system, which laid the foundation for further research on the performance of denitrification phosphorus removal in the system. The experimental results under different conditions showed that shortcut nitrification in the MBR was achieved by controlling the dissolved oxygen （DO） concentration to low levels （0. 5-1. 0 mg·L - 1 to 0. 3-0. 7 mg·L - 1 ） and changing the effective volume of the MBR to control hydraulic retention time （HRT）, with the HRT in the ABR equal to 6 h, sludge reflux ratio of 100% , NO -x -N reflux ratio of 300% , and temperature of 30℃ ± 2℃. Finally, the shortcut nitrification deteriorated as the HRT in the MBR increased from 3 h to 5 h, with nitrite accumulation rate dramatically dropping from 60% to 15% . The analysis of the influencing factors of shortcut nitrification showed that maintaining low DO concentration （0. 3-0. 7 mg·L - 1 ） and gradually shortening HRT were the key factors. The pH, free ammonia （FA）, free nitrous acid （FNA）, temperature, and sludge retention time （SRT） had a slightly positive effect on shortcut nitrification. During the period of shortcut nitrification, a stable and high efficiency removal of COD and NH ＋4 -N were achieved, and the average concentration of the effluent of COD and NH ＋4 -N, whose removal rates were above 90% , were below 50 mg·L - 1 and 2 mg·L - 1 , respectively, and the removal efficiency of total nitrogen （TN） reached 72% .