title: Evaluating the feasibility of ratio control strategy for achieving partial nitritation in a continuous floccular sludge reactor: Experimental demonstration.
abstract: To investigate the applicability of ratio control strategy to other systems, a continuous floccular sludge reactor was used in this study. It was found that nitrite accumulation was barely detected throughout 70days' investigation, being the average concentration in the effluent of 0.7±0.4mg/L. Batch experiments indicated that low dissolved oxygen (DO<0.3mg·L-1) greatly repressed the ammonium oxidizing bacteria (AOB) but only slightly inhibited the nitrite oxidizing bacteria (NOB). However, high-throughput sequencing revealed that the ratio of abundance between Nitrospira and Nitrosomonas, being the dominant NOB and AOB respectively, was considerably low (1.2%/18.7%). The weak oxygen gradients in floccular sludge and the selectively enriched K-strategist NOB Nitrospira under oxygen-limited conditions were both contributed to the failure of achieving partial nitritation; therefore, the rapid start-up of partial nitritation process based on proposed ratio control strategy is not feasible for continuous floccular sludge systems treating low-strength wastewater.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai, China.
authors.forename: Wenru
authors.initials: W
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai, China. Electronic address: yangdianhai@tongji.edu.cn.
authors.forename: Dianhai
authors.initials: D
authors.lastname: Yang
mesh_terms: D064751:Ammonium Compounds / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D019149:Bioreactors / Q000382:microbiology; D009573:Nitrites / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D009606:Nitrosomonas / Q000145:classification / Q000378:metabolism; D010100:Oxygen / Q000032:analysis; D012722:Sewage / Q000737:chemistry / Q000382:microbiology; D062065:Wastewater / Q000737:chemistry* / Q000382:microbiology; D018508:Water Purification / Q000379:methods*
chemical_list: D064751:Ammonium Compounds; D009573:Nitrites; D010100:Oxygen; D012722:Sewage; D062065:Wastewater
keywords: Ammonium excess; Flocs; Low dissolved oxygen; Nitrosomonas; Nitrospira; Partial nitritation