Orbal氧化沟工艺污水厂中关键酶活性对污水处理效率的影响

Effect of key enzyme activities on the operating efficiency in wastewater treatment plant with Orbal oxidation ditch

针对实际污水处理厂提标改造过程中运行参数变化对运行效果产生影响机制不明确的问题,选取以Orbal氧化沟为核心工艺的某实际污水处理厂,设置2种运行模式,采用PCR-DGGE分析、实时荧光定量PCR分析、酶活性分析等方法研究了不同运行模式下活性污泥中微生物种群结构、功能微生物含量、关键酶活性的特征;分析了微生物种群、关键酶活性与污染物去除率之间的关系;探讨了Orbal氧化沟工艺中运行参数变化对运行效果产生影响的机制。结果表明:适当减少Orbal氧化沟外侧沟道内转刷的开启数量,其沟道内溶解氧分布将发生明显变化;沿水流方向,厌氧或缺氧段将明显延长;长期运行结果显示,进水水质稳定时,减少转刷开启数量没有对生物处理工段内微生物种群结构产生影响。同时,外侧沟道内硝酸还原酶(nitrate reductase, NR)活性(以羟胺计)在夏季和冬季却均有显著增加,分别由模式Ⅰ的1.58 mg·(g·h)-1和0.80 mg·(g·h)-1增加到了模式Ⅱ的2.27 mg·(g·h)-1和1.07 mg·(g·h)-1;相关分析表明,HAO和NR活性与氨氮和总氮去除率呈显著相关,斯皮尔曼相关系数r分别为0.99(P=0.01)和0.88(P=0.12)。在实际污水处理厂中,关键酶活性是运行参数改变对运行效率产生影响的根本原因。

During the upgrade processes of full-scale wastewater treatment plant(WWTP),the effect mechanism of operation parameters variations on WWTP performance is still unclear.A WWTP with Orbal oxidation ditch was selected and two operation modes were set up.Molecular biological methods e.g.polymerase chain reaction-denaturing gradient gel electrophoresis(PCR-DGGE),real-time quantitative PCR and enzyme activity analysis were used to study the microbial population,functional microbial content and key enzyme activity in activated sludge under different operation modes,and the relationships between the microbial population,key enzyme activity and pollutant removal efficiency were analyzed.The effect mechanism of the parameters on the Orbal oxidation ditch performance was also discussed.The results showed that an obvious change in the dissolved oxygen(DO)distribution in the outer channel occurred when properly reducing the number of operating brushes in Orbal oxidation ditch.As a result,the anaerobic or anoxic zone extended significantly along the direction of water flow.The results of long-term operation indicated that the number reduction of operating brushes did not affect the microbial population structure in the biological treatment section when the water quality of influent was stable.At the same time,the nitrate reductase(NR)activities in outer channel(calculated by hydroxylamine)in summer and winter increased significantly from 1.58 mg·(g·h)-1 and 0.80 mg·(g·h)-1 under mode I to 2.27 mg·(g·h)-1 and 1.07 mg·(g·h)-1 under mode II,respectively.Correlation analysis indicated that the activities of hydroxylamine oxidoreductase(HAO)and NR had positive relationship with removal efficiencies of NH4+-N and TN,and the corresponding correlation coefficients were 0.99(P=0.01)and 0.88(P=0.12),respectively.In the full-scale WWTP,the key enzyme activity was the fundamental reason of parameters variations on the operating efficiency.