Study on microbial characteristics of the ultra-short sludge retention time activated sludge system

As an enhanced process for high-rate activated sludge (HRAS) systems, the ultra-short sludge retention time (SRT) activated sludge (USSAS) process can achieve high efficiency carbon separation, energy savings and resource recovery potential, this study deeply investigated the microbial community cha...

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Main Authors: Yuting Shao, Han Zhang, Chongqing Xu, Guihuan Yan, Hongchen Wang, Guo-hua Liu, Lu Qi
Format: Article
Language:English
Published: Elsevier 2025-06-01
Series:Results in Engineering
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Online Access:http://www.sciencedirect.com/science/article/pii/S2590123025016305
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author Yuting Shao
Han Zhang
Chongqing Xu
Guihuan Yan
Hongchen Wang
Guo-hua Liu
Lu Qi
author_facet Yuting Shao
Han Zhang
Chongqing Xu
Guihuan Yan
Hongchen Wang
Guo-hua Liu
Lu Qi
author_sort Yuting Shao
collection DOAJ
description As an enhanced process for high-rate activated sludge (HRAS) systems, the ultra-short sludge retention time (SRT) activated sludge (USSAS) process can achieve high efficiency carbon separation, energy savings and resource recovery potential, this study deeply investigated the microbial community characteristics and the microbial kinetic behavior of activated sludge of the USSAS system. The results showed that, compared with conventional activated sludge (CAS), the USSAS system can screen microorganisms with different functions and generation cycles. The microbial community diversity in the USSAS system was 80% of that in CAS, and the dominant bacteria were mostly microorganisms with short generation cycles and filamentous bacteria that can cause instability such as sludge bulking. Additionally, HRT=2 h is the critical point of the system from stability to functionality. In the USSAS system, with increasing SRT, the specific oxygen uptake rate gradually increased, the activity of sludge was enhanced, and the maximum activity was observed at the SRT of 3 d. Additionally, the values of sludge observed yield (Yobs), heterotrophic bacteria yield coefficient (YH) and heterotrophic bacteria attenuation coefficient (KdH) all increased with SRT and were all higher than those at CAS, the microorganisms in the USSAS system renewed faster, and the heterotrophic bacteria that can utilize organic matter rapidly can dominate the system and multiply rapidly. However, the maximum specific removal rate of COD (VmS) was lower than CAS, means the USSAS system had a lower biodegradation capacity and a higher biosorption capacity.
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spelling doaj-art-7a9f0b70c2ff46b08d54c109db84255b2025-08-20T03:25:08ZengElsevierResults in Engineering2590-12302025-06-012610556010.1016/j.rineng.2025.105560Study on microbial characteristics of the ultra-short sludge retention time activated sludge systemYuting Shao0Han Zhang1Chongqing Xu2Guihuan Yan3Hongchen Wang4Guo-hua Liu5Lu Qi6School of Environmental Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, PR ChinaShandong Normal University, Jinan 250353, PR ChinaSchool of Environmental Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, PR China; Shandong Technology Innovation Center of Carbon Neutrality, Ecology Institute of Shandong Academy of Sciences, Jinan 250353, PR ChinaShandong Technology Innovation Center of Carbon Neutrality, Ecology Institute of Shandong Academy of Sciences, Jinan 250353, PR ChinaResearch Center for Low Carbon Technology of Water Environment, Renmin University of China, Beijing 100872, PR China; Corresponding author.Research Center for Low Carbon Technology of Water Environment, Renmin University of China, Beijing 100872, PR ChinaResearch Center for Low Carbon Technology of Water Environment, Renmin University of China, Beijing 100872, PR ChinaAs an enhanced process for high-rate activated sludge (HRAS) systems, the ultra-short sludge retention time (SRT) activated sludge (USSAS) process can achieve high efficiency carbon separation, energy savings and resource recovery potential, this study deeply investigated the microbial community characteristics and the microbial kinetic behavior of activated sludge of the USSAS system. The results showed that, compared with conventional activated sludge (CAS), the USSAS system can screen microorganisms with different functions and generation cycles. The microbial community diversity in the USSAS system was 80% of that in CAS, and the dominant bacteria were mostly microorganisms with short generation cycles and filamentous bacteria that can cause instability such as sludge bulking. Additionally, HRT=2 h is the critical point of the system from stability to functionality. In the USSAS system, with increasing SRT, the specific oxygen uptake rate gradually increased, the activity of sludge was enhanced, and the maximum activity was observed at the SRT of 3 d. Additionally, the values of sludge observed yield (Yobs), heterotrophic bacteria yield coefficient (YH) and heterotrophic bacteria attenuation coefficient (KdH) all increased with SRT and were all higher than those at CAS, the microorganisms in the USSAS system renewed faster, and the heterotrophic bacteria that can utilize organic matter rapidly can dominate the system and multiply rapidly. However, the maximum specific removal rate of COD (VmS) was lower than CAS, means the USSAS system had a lower biodegradation capacity and a higher biosorption capacity.http://www.sciencedirect.com/science/article/pii/S2590123025016305Low-carbon wastewater treatmentUltra-short sludge retention time activated sludgeMicrobial kinetics
spellingShingle Yuting Shao
Han Zhang
Chongqing Xu
Guihuan Yan
Hongchen Wang
Guo-hua Liu
Lu Qi
Study on microbial characteristics of the ultra-short sludge retention time activated sludge system
Results in Engineering
Low-carbon wastewater treatment
Ultra-short sludge retention time activated sludge
Microbial kinetics
title Study on microbial characteristics of the ultra-short sludge retention time activated sludge system
title_full Study on microbial characteristics of the ultra-short sludge retention time activated sludge system
title_fullStr Study on microbial characteristics of the ultra-short sludge retention time activated sludge system
title_full_unstemmed Study on microbial characteristics of the ultra-short sludge retention time activated sludge system
title_short Study on microbial characteristics of the ultra-short sludge retention time activated sludge system
title_sort study on microbial characteristics of the ultra short sludge retention time activated sludge system
topic Low-carbon wastewater treatment
Ultra-short sludge retention time activated sludge
Microbial kinetics
url http://www.sciencedirect.com/science/article/pii/S2590123025016305
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