膜序批式生物反应器脱氮性能研究

Investigation of Nitrogen Removal Performance with Membrane Sequencing Batch Reactor Process

采用厌-好氧交替膜序批式反应器,实验室人工合成配水,连续运行300d,对反应器脱氮性能进行了研究。结果表明,污泥浓度达到18g·L^-1时,污泥粒径大小在100μm以上的占96%,污泥出现颗粒化。FISH-CLSM分析AOB及NOB的群落空间分布表明它们在污泥中大量存在。NH4^＋-N进水50mg·L-1左右时出水在1mg·L^-1以下,硝化反应在180-210min就可以完成。曝气强度与硝化反应速率密切相关,曝气强度为100m3·（m^2·h）^-1时,NH4＋-N降解速率最佳达24.25mg·（L·h）^-1,系统硝化性能稳定。影响系统脱氮的主要因素是反硝化速率,曝气强度为69m^3·（m^2·h）^-1时,对NO3^--N的利用率为10.98mg·（L·h）^-1,出水NO3^--N浓度为4.4mg·L^-1,滞留在厌氧段的浓度3.5mg·L^-1为最低,反硝化效果最好。曝气过量或不足时反硝化速率都低。在保证系统处理能力的同时,大的交换比0.35有利于系统脱氮运行。C/N比为2时,反硝化速率最高,〉2时出现NO2^--N的积累。

Nitrogen removal performance was investigated using synthetic wastewater as feed without sludge discharge in an anaerobic/aerobic membrane sequencing batch reactor （MSBR） during 300 clays operation. The results showed that MISS in reactor was retained up to about 18 g·L^-1, sludge size larger than 100 μm was 96%, and aerobic granular sludge was developed. The bacterial community observation of AOB and NOB by FISH-CISM for sludge revealed that they were existed in larger numbers. When influent NH4^＋ -N concentration was about 50 mg·L^-1, effluent NH4^＋ -N concentration was lower than to 1 mg·L^-1, and nitrification could complete in 180-210 min. There was a good correlation between nitrification reaction and aeration strength. When aeration strength was 100 m^3·（m^2·h）^-1, NH4^＋ -N degradation rate 24.25 mg·（L·h）^-1, and nitrification reaction in MSBR was stable. The main factor determining nitrogen removal of the system was denitrification rate, which was optimal at aeration 69 m^3·（m^2·h）^-1, when the nitrification rate of NO3^-N 10.98 mg·（L·h）^-1, effluent NO3^-N 4.4 mg·L^-1 , and NO3^- -N in the beginning of anaerobic phase 3.5 mg·L^-1. The denitrification performance was not benefited by excessive aeration or deficient aeration. Bigger volumetric exchange ratio was helpful for nitrogen removal and the system treatment capacity. The C/N ratio 2 was suitable to good denitrification rate, while there was a NO2^- -N accumulation if C/N ratio was larger than 2.