The composition was as follows: 13 mg L 1 NH 4 Cl, 17 mg L 1 peptone, 79 mg L 1 NaAc, 122 mg L 1 starch, 116 mg L 1 low fat milk powder, 52 mg L 1 yeast, 92 mg L 1 urea, 23 mg L 1 KH 2 PO 4, and 5.8 mg L 1 FeSO 4 7H 2 O.This Open Access Article is licensed under a Creative Commons Attribution-Non Commercial 3.0 Unported Licence DOI: 10.1039D0RA05252C.
![]() The ratio of nitrite oxidizing bacteria (NOB) to ammonia oxidizing bacteria (AOB) increased from 0.84 to 2.14 after cultivation. The Illumina MiSeq sequencing showed that the dominant AOB was Nitrosomonas sp. Nm84 and unidentified species, and the three most abundant Nitrospira were Nitrospira defluvii, Nitrospira calida, and unidentified Nitrospira spp. The shared reads of raw sewage and activated sludge were 48.76 for AOB and 89.35 for Nitrospira. These indicated that nitrifiers, especially NOB, immigrated from influent can survive and propagate in wastewater systems, which may be a significant hinder to suppress NOB in the application of advanced nitrogen remove process based on partial nitrification in the mainstream. Raw Data Aob Extractor How To Stably AndBesides, how to stably and sustainably eliminate nitrite oxidizing bacteria (NOB) is still the main bottleneck in the application of advanced mainstream biological nitrogen removal (BNR) technologies based on partial nitrification. Thus, the microorganism community of nitrifiers has attracted more and more attention in the field of biological wastewater treatment design and operation. ![]() In order to counterbalance this removal in the system, the number of organisms must increase at a rate of 1SRT per day. This increase is generally considered to be caused by the net growth of bacteria in the bioreactor. Meanwhile, a continuous supply of nitrifiers, especially NOB, immigrated from raw sewage is very likely to have an adverse effect on achieving partial nitrification in the mainstream application. Therefore, immigration from sewers to wastewater treatment systems is attracting increasing attention for understanding community assembly mechanisms and improving process modeling and operation. While so far, almost all of the studies previously discussed were based on the investigation of the similarity of the influent and activated sludge nitrifier communities. Comparatively few experiments have been designed directly to understand how the influent nitrifiers grow and persist in environmental conditions prevalent in WRRFs. The floc size, nitrification performance, and nitrifier community were investigated to explore the process of the survival and reproduction of the influent nitrifiers in activated sludge bioreactors and evaluate the impact of nitrifier immigration from influent on nitrifier community assembly. Raw Data Aob Extractor Full Nitrification InUsing this basis, we provided new insight into achieving full nitrification in cold northern regions and meanwhile proposes a great challenge of suppressing NOB in the application of advanced BNR process based on partial nitrification in the mainstream. Throughout, the reactor temperature was maintained at 20 1 C. The processes of influent, effluent and sludge discharge were controlled by a programmable logic controller (PLC) using the peristaltic pumps. In addition, airflow rate was kept constant and average dissolved oxygen (DO) concentration during an operating cycle was above 2.5 mg L 1. H was maintained at 7.58.0 by manually adding 1.0 M NaHCO 3 to maintain the alkalinity required for nitrification. The characteristics of the 2 nd WRRF and influent sewage were described in ESI (Tables S1 and S2 ). On the sixth day, once the ammonium was completely degraded, the reactor began operation for 90 days. Each cycle consisted of feeding (5 min), aeration (depending on the operating cycle time of different phases), settling (40 min), decanting (5 min) and idle time (10 min). Once the mixed liquor volatile suspended solids (MLVSS) is close to the value of the 2 nd WRRF in Xian (2.35 g L 1 ), a specific volume of activated sludge was discharged prior to the end of the aeration phase to keep the SRT at 1520 days.
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