菌藻共生系统实现短程硝化工艺的藻供氧条件和影响因素分析

STUDY ON OXYGEN SUPPLY CONDITION AND INFLUENCE OF ALGAL IN PARTIAL NITRIFICATION PROCESS IN A BACTERIA AND ALGAE SYMBIOTIC SYSTEM

通过调节光照强度和藻浓度来实现最佳的短程硝化工艺,探究了光照强度和藻浓度对反应器出水水质、溶解氧(DO)浓度、氨氧化菌(AOB)数量和酶活、藻光合作用色素含量以及微生物形貌及群落结构的影响。水质测定结果表明:在16000 Lux光照强度和添加1170 mL小球藻培养液(OD680=1.6±0.4)的条件下,亚硝酸盐积累率达到88.88%,实现了良好的短程硝化效果。DO监测结果表明:反应器中ρ(DO)一直在0.1~0.11 mg/L,并且藻浓度是反应器中DO浓度的主要影响因素。AOB菌的氨单加氧酶(ammonia monooxygenase,AMO)活性和amoA基因拷贝数,以及藻的3种光合作用色素含量在反应器运行后期逐渐趋于稳定,说明反应器内AOB菌和藻逐渐形成了稳定的共生系统。高通量测序结果显示,AOB菌属Nitrosomonas和小球藻属Chlorella是主要的功能微生物,并且扫描电子显微镜观察到2种功能微生物的形貌。通过探究不同藻供氧条件对短程硝化工艺中功能微生物活性、数量和微生物群落结构的影响,为该工艺启动和稳定运行的藻供氧调控提供了理论参考。

In this study,the optimal partial nitrification(PN)process was achieved by adjusting the light intensity and algae concentration,and their effects on effluent quality,dissolved oxygen(DO)concentration,the number and enzyme activity of ammonia oxidizing bacteria(AOB),the content of algae photosynthetic pigments,microbial morphology and community structure were investigated.The results of water quality measurement showed that the nitrite accumulation rate reached 88.88%under the condition of 16000 Lux illumination intensity and 1170 mL Chlorella culture solution(OD_(680)=1.6±0.4),achieving a good PN effect.The DO monitoring results showed that the reactor was always in the concentration range of 0.1~0.11 mg/L,and the algae concentration was the main factor affecting the DO concentration in the reactor.The ammonia monooxygenase(AMO)activity and amoA gene copy number of AOB bacteria,and the concentration of three photosynthetic pigments of algae gradually stabilized at the later stage of reactor operation,indicating that AOB bacteria and algae gradually formed a stable symbiotic system in the reactor.High-throughput sequencing results showed that Nitrosomonas and Chlorella were the main functional microorganisms,and the morphologies of two functional microorganisms were observed by scanning electron microscopy.In this paper,the effect of different algal oxygen supply conditions on the activity,quantity of functional microorganisms and microbial community structure in the PN process were investigated,which provided a theoretical reference for regulating algal oxygen supply during the start-up and stable operation of the process.