微藻生物强化对藻-菌颗粒污泥的形成影响及污染物去除研究

为了探究微藻强化好氧颗粒污泥(aerobic granular sludge, AGS)方式培养藻-菌颗粒污泥(microalgal-bacterial granular sludge, MBGS)的可行性及其关键藻种的潜在作用机理，分别向序批式光生物反应器(光强4 000 lx)中投加小球藻(R1反应器)，小球藻和斜生栅藻(R2反应器)，小球藻、斜生栅藻和鲍氏细鞘丝藻(R3反应器)，并对形成的MBGS理化特性、污染物去除及微生物群落结构进行系统研究. 结果表明:①MBGS均能在30 d左右形成，其稳态下的污染物去除总体优于AGS，对COD、NH₄+-N、TN和TP的平均去除率分别在98%、97%、77%和93%以上，且R2、R3反应器对NH₄+-N、TP的去除率显著高于R1反应器(P<0.05). ②胞外聚合物(EPS)分析表明，与R1反应器相比，R2、R3反应器具有更多的芳香蛋白、可溶性微生物副产物、腐殖酸、类富里酸等成分，有利于MBGS的形成. ③R3反应器中鲍氏细鞘丝藻被淘汰，形成了与R2反应器主要藻种类似的MBGS. ④R1、R2和R3反应器稳态下具有硝化螺旋菌门(Nitrospirae)和红环菌科(Rhodocyclaceae)等脱氮除磷功能微生物. 研究显示，在微藻生物强化形成MBGS的过程中，斜生栅藻可能起到重要作用，提高了氮、磷的去除率，并有利于维持MBGS的稳定性. 

Effect of Microalgae Bio-Augmentation on Formation of Microalgal-Bacterial Granular Sludge and the Pollutants Removal

In order to explore the feasibility of microalgal-bacterial granular sludge (MBGS) cultivation from aerobic granular sludge (AGS) and the potential function of key algae species, Chlorella pyrenoidosa (R1 reactor), Chlorella pyrenoidosa and Scenedesmus obliquus (R2 reactor), Chlorella pyrenoidosa, Scenedesmus obliquus, and Leptolyngbya boryana (R3 reactor) were added to the sequencing batch photobioreactor (light intensity of 4 000 lx). The physicochemical characteristics of MBGS, pollutants removal performance and microbial community structure were systematically studied. The results showed that: (1) MBGS could be formed in about 30 days, and the pollutant removal performance under steady state was generally better than that of AGS. The average removal efficiencies of COD, NH₄+-N, TN and TP were over 98%, 97%, 77% and 93% for MBGS, respectively, while the NH₄+-N and TP removal efficiencies of R2 and R3 reactor were significantly higher than that of R1 reactor (P<0.05). (2) The analysis of extracellular polymeric substances (EPS) showed that R2 and R3 reactor had more aromatic proteins, soluble microbial byproduct, humic acid, fulvic acid, etc. as compared with R1 reactor, which were conducive to the formation of MBGS. (3) Leptolyngbya boryana in R3 reactor was eliminated and the formed MBGS contained the main algae species as R2 reactor. (4) R1, R2 and R3 reactor had more abundant functional microorganisms for nitrogen and such as Nitrospirae and Rhodocyclaceae during the steady state. The study showed that Scenedesmus obliquus might play an important role in the MBGS cultivation by microalgae bio-augmentation, which improved nitrogen and phosphorus removal as well as the MBGS stability.