Effect of sludge retention time on microbial succession and assembly in thermal hydrolysis pretreated sludge digesters: deterministic versus stochastic processes
Thermal hydrolysis process (THP) assisted anaerobic digestion (AD) has been demonstrated to be an efficient approach to improve biogas production and solids reduction. Given the faster reaction kinetics in the THP-AD system, reduction of sludge retention time (SRT) is possible. However, a comprehens...
| Main Authors: | , , , , , |
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| Other Authors: | |
| Format: | Journal Article |
| Language: | English |
| Published: |
2022
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| Online Access: | https://hdl.handle.net/10356/161809 |
| _version_ | 1811684327785758720 |
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| author | Zhang, Liang Guo, Kun Wang, Li Xu, Ronghua Lu, Dan Zhou, Yan |
| author2 | School of Civil and Environmental Engineering |
| author_facet | School of Civil and Environmental Engineering Zhang, Liang Guo, Kun Wang, Li Xu, Ronghua Lu, Dan Zhou, Yan |
| author_sort | Zhang, Liang |
| collection | NTU |
| description | Thermal hydrolysis process (THP) assisted anaerobic digestion (AD) has been demonstrated to be an efficient approach to improve biogas production and solids reduction. Given the faster reaction kinetics in the THP-AD system, reduction of sludge retention time (SRT) is possible. However, a comprehensive understanding of the effects of sludge retention time (SRT) on microbial dynamics and community assemblages is still lacking in THP-AD systems. Thus, twelve THP-AD reactors were operated at different SRTs (10-30 d) to fulfill the knowledge gap. Results showed that, although all the bioreactors displayed good performance, shorter SRT reactors (SRT 10 d) took a longer time to reach the stable state. The total biogas production at SRT of 10 d was lower than that at other longer SRTs, attributing to the limited hydrolytic/fermentative capacities of AD microbiomes. Different SRTs resulted in distinct succession patterns of AD microbiomes. THP sludge reduced the microbial diversity in all the bioreactors over time, but longer SRTs maintained higher biodiversity. Null model analysis suggested that THP-AD microbial community assembly was predominately driven by deterministic selection at the tested SRT range, but stochasticity increased with elevated SRTs, likely attributing to the immigrants from the feedstock. Phylogenetic molecular ecological networks (pMENs) analysis revealed more stable network structures at longer SRTs, evidenced by the lower modularity, shorter harmonic geodesic distance, and higher connectivity. The potential keystone taxa under varied SRTs were identified, some of which were hydrolytic/fermentative bacteria (e.g., Peptostreptococcus, Lutispora, Synergistaceae), suggesting that these species related to organic hydrolysis/fermentation even with low-abundance could still play pivotal ecological roles in maintaining the THP-AD microbial community structure and functions. Collectively, this study provides comprehensive and in-depth insights into the mechanisms underlying community assembly in THP-AD reactors, which could aid in diagnosing system stability. |
| first_indexed | 2024-10-01T04:26:52Z |
| format | Journal Article |
| id | ntu-10356/161809 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T04:26:52Z |
| publishDate | 2022 |
| record_format | dspace |
| spelling | ntu-10356/1618092022-09-20T07:38:46Z Effect of sludge retention time on microbial succession and assembly in thermal hydrolysis pretreated sludge digesters: deterministic versus stochastic processes Zhang, Liang Guo, Kun Wang, Li Xu, Ronghua Lu, Dan Zhou, Yan School of Civil and Environmental Engineering Nanyang Environment and Water Research Institute Advanced Environmental Biotechnology Centre (AEBC) Engineering::Environmental engineering Anaerobic Digestion Ecological Network Thermal hydrolysis process (THP) assisted anaerobic digestion (AD) has been demonstrated to be an efficient approach to improve biogas production and solids reduction. Given the faster reaction kinetics in the THP-AD system, reduction of sludge retention time (SRT) is possible. However, a comprehensive understanding of the effects of sludge retention time (SRT) on microbial dynamics and community assemblages is still lacking in THP-AD systems. Thus, twelve THP-AD reactors were operated at different SRTs (10-30 d) to fulfill the knowledge gap. Results showed that, although all the bioreactors displayed good performance, shorter SRT reactors (SRT 10 d) took a longer time to reach the stable state. The total biogas production at SRT of 10 d was lower than that at other longer SRTs, attributing to the limited hydrolytic/fermentative capacities of AD microbiomes. Different SRTs resulted in distinct succession patterns of AD microbiomes. THP sludge reduced the microbial diversity in all the bioreactors over time, but longer SRTs maintained higher biodiversity. Null model analysis suggested that THP-AD microbial community assembly was predominately driven by deterministic selection at the tested SRT range, but stochasticity increased with elevated SRTs, likely attributing to the immigrants from the feedstock. Phylogenetic molecular ecological networks (pMENs) analysis revealed more stable network structures at longer SRTs, evidenced by the lower modularity, shorter harmonic geodesic distance, and higher connectivity. The potential keystone taxa under varied SRTs were identified, some of which were hydrolytic/fermentative bacteria (e.g., Peptostreptococcus, Lutispora, Synergistaceae), suggesting that these species related to organic hydrolysis/fermentation even with low-abundance could still play pivotal ecological roles in maintaining the THP-AD microbial community structure and functions. Collectively, this study provides comprehensive and in-depth insights into the mechanisms underlying community assembly in THP-AD reactors, which could aid in diagnosing system stability. Nanyang Technological University The authors acknowledge the financial support of Advanced Environmental Biotechnology centre, Nanyang Environment and Water Research Institute (NEWRI), Nanyang Technological University. 2022-09-20T07:38:46Z 2022-09-20T07:38:46Z 2022 Journal Article Zhang, L., Guo, K., Wang, L., Xu, R., Lu, D. & Zhou, Y. (2022). Effect of sludge retention time on microbial succession and assembly in thermal hydrolysis pretreated sludge digesters: deterministic versus stochastic processes. Water Research, 209, 117900-. https://dx.doi.org/10.1016/j.watres.2021.117900 0043-1354 https://hdl.handle.net/10356/161809 10.1016/j.watres.2021.117900 34902758 2-s2.0-85120944210 209 117900 en Water Research © 2021 Elsevier Ltd. All rights reserved. |
| spellingShingle | Engineering::Environmental engineering Anaerobic Digestion Ecological Network Zhang, Liang Guo, Kun Wang, Li Xu, Ronghua Lu, Dan Zhou, Yan Effect of sludge retention time on microbial succession and assembly in thermal hydrolysis pretreated sludge digesters: deterministic versus stochastic processes |
| title | Effect of sludge retention time on microbial succession and assembly in thermal hydrolysis pretreated sludge digesters: deterministic versus stochastic processes |
| title_full | Effect of sludge retention time on microbial succession and assembly in thermal hydrolysis pretreated sludge digesters: deterministic versus stochastic processes |
| title_fullStr | Effect of sludge retention time on microbial succession and assembly in thermal hydrolysis pretreated sludge digesters: deterministic versus stochastic processes |
| title_full_unstemmed | Effect of sludge retention time on microbial succession and assembly in thermal hydrolysis pretreated sludge digesters: deterministic versus stochastic processes |
| title_short | Effect of sludge retention time on microbial succession and assembly in thermal hydrolysis pretreated sludge digesters: deterministic versus stochastic processes |
| title_sort | effect of sludge retention time on microbial succession and assembly in thermal hydrolysis pretreated sludge digesters deterministic versus stochastic processes |
| topic | Engineering::Environmental engineering Anaerobic Digestion Ecological Network |
| url | https://hdl.handle.net/10356/161809 |
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