Free ammonia resistance of nitrite‐oxidizing bacteria developed in aerobic granular sludge cultivated in continuous upflow airlift reactors performing partial nitritation

Abstract The presence of toxic compounds in wastewater can cause problems for organic matter and nutrient removal. In this study, the long term effect of a model xenobiotic, 2-fluorophenol (2-FP), on ammonia oxidizing bacteria (AOB), nitrite oxidizing bacteria (NOB) and phosphate accumulating organisms (PAO) in aerobic granular sludge was investigated. Phosphate (P) and ammonium (N) removal efficiencies were high (>93%) and, after bioaugmentation with 2-FP degrading strain FP1, 2-FP was completely degraded. Neither N nor P removal were affected by 50 mg L−1 of 2-FP in the feed stream. Changes in the aerobic granule bacterial communities were followed. Numerical analysis of the denaturing gradient gel electrophoresis (DGGE) profiles showed low diversity for the amoA gene with an even distribution of species. PAOs, including denitrifying PAO (dPAO), and AOB were present in the 2-FP degrading granules, although dPAO population decreased throughout the 444 days reactor operation. The results demonstrated that the aerobic granules bioaugmented with FP1 strain successfully removed N, P and 2-FP simultaneously.

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Achieving high-rate partial nitritation with aerobic granular sludge at low temperatures

Biodegradation ◽

10.1007/s10532-021-09965-8 ◽

2021 ◽

Author(s):

Wenru Liu ◽

Yaoliang Shen ◽

Dianhai Yang

Keyword(s):

Low Temperatures ◽

Granular Sludge ◽

High Rate ◽

Aerobic Granular Sludge ◽

Partial Nitritation

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Effects of the Food-to-Microorganism (F/M) Ratio on N2O Emissions in Aerobic Granular Sludge Sequencing Batch Airlift Reactors

Water ◽

10.3390/w9070477 ◽

2017 ◽

Vol 9 (7) ◽

pp. 477 ◽

Cited By ~ 4

Author(s):

Ning Guo ◽

Jian Zhang ◽

Hui-Jun Xie ◽

Lin-Rui Tan ◽

Jie-Ning Luo ◽

...

Keyword(s):

Granular Sludge ◽

Aerobic Granular Sludge ◽

N2o Emissions ◽

Airlift Reactors

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An Attempt to Develop Aerobic Granular Sludge in Continuous Airlift Reactors

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1025.265 ◽

2021 ◽

Vol 1025 ◽

pp. 265-272

Author(s):

Muhammad Syafiq Mohd Shafei ◽

Zulkifly Jemaat

Keyword(s):

Wastewater Treatment ◽

Operation Mode ◽

Treatment Plant ◽

Granular Sludge ◽

Cod Removal ◽

Aerobic Granular Sludge ◽

Organic Loading Rate ◽

Aerobic Granules ◽

Reactor Performance ◽

Airlift Reactors

Recent advancement on biological wastewater treatment is via granular sludge technology. It is widely known that, aerobic granular sludge has been developed in a batch operation since its discovery. Yet, most of the wastewater treatment plant (WWTP) is operated in continuous mode. Now, the real challenge is how to adopt the granular technology while maintaining present operation mode of WWTP. Thus, this study attempts to evaluate the feasibility of developing aerobic granular sludge in continuous airlift reactors feed with two different substrates, namely glucose and acetate. Two identical airlift reactors (6 L) were employed and operated at room temperature (30°C). Prior to the substrate feeding, both reactors were inoculated with seed sludge obtained from a palm oil mill anaerobic pond. One of the reactors was fed with 2000 mg COD L-1 of glucose (ALR1) and the other reactor with 2000 mg COD L-1 of acetate (ALR2). The hydraulic retention time (HRT) and organic loading rate (OLR) for both reactors were maintained at 4 days and between 0.2 to 0.5 kg m-3day-1 respectively. Dissolved oxygen was maintained between 5.0 and 6.0 mg O2L-1 and supplied by air compressor. The reactor performance was monitored based on COD removal. Aerobic granules developed throughout the study period was evaluated based on granules size and morphology, sludge volumetric index (SVI30) and SVI5/SVI30 ratio analysis. Results showed that ALR1 demonstrated the formation of filamentous-type aerobic granules with most of the SVI30 average at 100 to 190 mL g-1. Ratio SVI5/SVI30 analysis was evaluated at 0.2 and 0.5. The largest granules size obtained during the experiment was about 600 μm on day-136 and average granules size obtained at 200 to 400 μm. ALR1 able to achieve 95% COD removal. For ALR2, round shaped aerobic granules were developed with average SVI30 from 100 to 1000 mLg-1. SVI5/SVI30 analysis indicated an average ratio between 0.7 and 0.9. The average granules size was between 30 to 50 μm and the largest was 78 μm on day-60. 90% of COD removal efficiency was obtained in ALR2. In conclusion, ALR fed with acetate had indicated better aerobic granules characteristics as compared to glucose fed reactor. Furthermore, the study demonstrated that to develop aerobic granules in continuous reactors is feasible.

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