scholarly journals Enhanced nitrite accumulation under mainstream conditions by a combination of free ammonia-based sludge treatment and low dissolved oxygen: reactor performance and microbiome analysis

RSC Advances ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 2049-2059 ◽  
Author(s):  
Heng Yu ◽  
Zhiyong Tian ◽  
Jiane Zuo ◽  
Yonghui Song
Keyword(s):  
Dissolved Oxygen ◽  
Free Ammonia ◽  
Nitrite Accumulation ◽  
Reactor Performance ◽  
Sludge Treatment ◽  
Low Dissolved Oxygen ◽  
Microbiome Analysis ◽  
Side Stream ◽  
Low Do

An introduction of the combination of side-stream sludge treatment using FA and low DO could more effectively enhance nitrite accumulation than single low DO.

scholarly journals Low-dissolved-oxygen nitrification in tropical sewage: an investigation on potential, performance and functional microbial community

2018 ◽  
Vol 77 (9) ◽  
pp. 2274-2283 ◽  
Author(s):  
S. W. How ◽  
S. Y. Lim ◽  
P. B. Lim ◽  
A. M. Aris ◽  
G. C. Ngoh ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Batch Reactor ◽  
In Situ Hybridisation ◽  
Sewage Treatment ◽  
Oxygen Affinity ◽  
Amplicon Sequencing ◽  
Fluorescence In Situ Hybridisation ◽  
Low Dissolved Oxygen ◽  
16S Rrna Amplicon Sequencing ◽  
Low Do

Abstract Intensive aeration for nitrification is a major energy consumer in sewage treatment plants (STPs). Low-dissolved-oxygen (low-DO) nitrification has the potential to lower the aeration demand. However, the applicability of low-DO nitrification in the tropical climate is not well-understood. In this study, the potential of low-DO nitrification in tropical setting was first examined using batch kinetic experiments. Subsequently, the performance of low-DO nitrification was investigated in a laboratory-scale sequential batch reactor (SBR) for 42 days using real tropical sewage. The batch kinetic experiments showed that the seed sludge has a relatively high oxygen affinity. Thus, the rate of nitrification was not significantly reduced at low DO concentrations (0.5 mg/L). During the operation of the low-DO nitrification SBR, 90% of NH4-N was removed. The active low-DO nitrification was mainly attributed to the limited biodegradable organics in the sewage. Fluorescence in-situ hybridisation and 16S rRNA amplicon sequencing revealed the nitrifiers were related to Nitrospira genus and Nitrosomonadaceae family. Phylogenetic analysis suggests 47% of the operational taxonomic units in Nitrospira genus are closely related to a comammox bacteria. This study has demonstrated active low-DO nitrification in tropical setting, which is a more sustainable process that could significantly reduce the energy footprint of STPs.

scholarly journals Response of nitrite accumulation and microbial community to free ammonia and dissolved oxygen treatment of high ammonium wastewater

2016 ◽  
Vol 100 (9) ◽  
pp. 4177-4187 ◽  
Author(s):  
Qianwen Sui ◽  
Chong Liu ◽  
Junya Zhang ◽  
Hongmin Dong ◽  
Zhiping Zhu ◽  
...  
Keyword(s):  
Microbial Community ◽  
Dissolved Oxygen ◽  
Free Ammonia ◽  
Nitrite Accumulation ◽  
Oxygen Treatment

scholarly journals Side-stream sludge treatment using free ammonia for reducing sludge production

2019 ◽  
Vol 25 (2) ◽  
pp. 163-170
Author(s):  
Kang Song ◽  
Xu Zhou ◽  
Yi-Wen Zhou ◽  
Wenbiao Jin ◽  
Renjie Tu
Keyword(s):  
Activated Sludge ◽  
Free Ammonia ◽  
Treatment Unit ◽  
Sludge Treatment ◽  
Effluent Quality ◽  
Side Stream ◽  
Sludge Properties ◽  
Treatment And Disposal ◽  
High Treatment ◽  
Sludge Production

Much attention has been paid to reducing of excess sludge production in the activated sludge process, due to high treatment and disposal costs. In this study, an innovative approach for achieving sludge reduction, which featured recirculating a portion of the activated sludge through a side-stream sludge treatment unit, was applied by adding free ammonia (FA, i.e., NH3). The results showed that sludge production was significantly reduced after FA treatment, while the sludge production rate was decreased by 21%. Meanwhile, the treatment performance and the sludge properties were not negatively affected by the FA-treated sludge during the experiment (e.g. effluent quality, nitrification activity, sludge settleability). Economic analysis also indicated that the FA treatment approach would be an economically favorable technology, and the sludge treatment costs could be cut by 16.6%.

Oxygen Requirements of Fishes in Northern Alberta Rivers with a General Review of the Adverse Effects of Low Dissolved Oxygen

1996 ◽  
Vol 31 (2) ◽  
pp. 361-410 ◽  
Author(s):  
Bruce A. Barton ◽  
Barry R. Taylor
Keyword(s):  
Dissolved Oxygen ◽  
Surface Film ◽  
Pulp Mill ◽  
Blood Chemistry ◽  
Acid Base Balance ◽  
Low Dissolved Oxygen ◽  
Base Balance ◽  
Oxygen Requirements ◽  
Northern Alberta ◽  
Low Do

Abstract Sublethal responses of fish to low dissolved oxygen (DO) include changes in cardiac function, increased respiratory and metabolic activity, alterations in blood chemistry, mobilization of anaerobic energy pathways, upset in acid-base balance, reduced growth and decreased swimming capacity. Lowered final temperature preferenda and avoiding low DO are behavioral responses, and under extreme conditions, fish may take advantage of oxygen-rich surface film water. Low DO can affect invertebrate communities by causing selective mortality or inducing drift, which may affect fish production. The presence of pollutants can exacerbate responses to low DO with the effect of raising the threshold DO at which such responses occur. Based on published literature, northern Alberta riverine fishes are grouped into four categories of acute lethal sensitivity. However, chronic DO requirements are far more important to long-term maintenance of healthy fish communities than acute tolerances. Defining chronic DO criteria for northern fishes is complicated by long periods of winter ice cover, possible presence of pulp mill effluent, and lack of information on many regional species. Although previously recommended criteria should provide a reasonable level of protection for fish, any reduction in DO below saturation will cause some production impairment within the aquatic community.

Nitrification of high strength ammonia wastewater and nitrite accumulation characteristics

2003 ◽  
Vol 47 (11) ◽  
pp. 45-51 ◽  
Author(s):  
D.J. Kim ◽  
J.S. Chang ◽  
D.I. Lee ◽  
D.W. Han ◽  
I.K. Yoo ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Deficiency ◽  
Biofilm Reactor ◽  
Free Ammonia ◽  
Limiting Factor ◽  
Nitrite Accumulation ◽  
Ammonium Oxidation ◽  
Nitrite Oxidation ◽  
Ammonia Inhibition ◽  
Nitrite Oxidizers

Biological nitrogen removal via the nitrite pathway in wastewater treatment is very important in saving the cost of aeration and as an electron donor for denitrification. Wastewater nitrification and nitrite accumulation were carried out in a biofilm airlift reactor with autotrophic nitrifying biofilm. The biofilm reactor showed almost complete nitrification and most of the oxidized ammonium was present as nitrite at the ammonium load of 1.5 to 3.5 kg N/m3·d. Nitrite accumulation was stably achieved by the selective inhibition of nitrite oxidizers with free ammonia and dissolved oxygen limitation. Stable 100% conversion to nitrite could also be achieved even under the absence of free ammonia inhibition on nitrite oxidizers. Batch ammonium oxidation and nitrite oxidation with nitrite accumulating nitrifying biofilm showed that nitrite oxidation was completely inhibited when free ammonia is higher than 0.2 mg N/L. However, nitrite oxidation activity was recovered as soon as the free ammonia concentration was below the threshold level when dissolved oxygen concentration was not the limiting factor. Fluorescence in situ hybridization analysis of cryosectioned nitrite accumulating nitrifying biofilm showed that the β-subclass of Proteobacteria, where ammonia oxidizers belong, was distributed outside the biofilm whereas the α-subclass of Proteobacteria, where nitrite oxidizers belong, was found mainly in the inner part of the biofilm. It is likely that dissolved oxygen deficiency or limitation in the inner part of the nitrifying biofilm, where nitrite oxidizers exist, is responsible for the complete shut down of the nitrite oxidizers activity under the absence of free ammonia inhibition.

scholarly journals Investigation of full-scale step-fed SBR under low dissolved oxygen: performance and microbial community response

2016 ◽  
Vol 51 (2) ◽  
pp. 141-152
Author(s):  
Heloísa Fernandes ◽  
Regina Vasconcellos Antonio ◽  
Rejane Helena Ribeiro da Costa
Keyword(s):  
Microbial Community ◽  
Dissolved Oxygen ◽  
Chemical Oxygen Demand ◽  
Suspended Solids ◽  
Oxygen Demand ◽  
Community Response ◽  
Full Scale ◽  
Low Dissolved Oxygen ◽  
Do Concentration ◽  
Low Do

A decentralized full-scale sequencing batch reactor (SBR) system for treating wastewater was operated to assess their feasibility and the response of bacterial population dynamic and nutrient removal performance. The reactor was operated under low dissolved oxygen (DO) concentration (0.3–0.7 mgL−1) and an average applied organic load of 0.5 g COD L−1 d−1 (COD: chemical oxygen demand). Removal efficiencies were higher than 70% for both soluble chemical oxygen demand and ammonium, with average effluent concentration of 51 ± 15 mg COD L−1 and 16.0 mg NH4+ L−1. The mixed liquor volatile suspended solids/total suspended solids ratio was 0.9, and the average food/microorganism ratio was 0.3 g COD g VSS−1 d−1 (VSS: volatile suspended solids). The active biomass was composed of 94.9% heterotrophic and 5.1% autotrophic organisms. The most frequently identified were chemoorganoheterotrophic organisms affiliated with Bacteroidetes and Firmicutes, some of them with the capacity to denitrify and grow under low DO concentration. Temperature and sludge withdrawal were important factors in determining nitrification and phosphorus removal rates. The SBR was viable for domestic wastewater treatment and showed that the microbial community greatly influenced its performance. This work can also provide valuable insights into further applications in systems operated under low DO condition.

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