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Lu J, Tan Y, Tian S, Qin Y, Zhou M, Hu H, Zhao X, Wang Z, Hu B. Effect of carbon source on carbon and nitrogen metabolism of common heterotrophic nitrification-aerobic denitrification pathway. CHEMOSPHERE 2024; 361:142525. [PMID: 38838867 DOI: 10.1016/j.chemosphere.2024.142525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 05/10/2024] [Accepted: 06/02/2024] [Indexed: 06/07/2024]
Abstract
Pseudomonas sp. ZHL02, removing nitrogen via ammonia nitrogen (NH4+) → hydroxylamine (HN2OH) → nitrite (NO2-) → nitrate (NO3-) → NO2- → nitric oxide (NO) → nitrous oxide (N2O) pathway was employed for getting in-depth information on the heterotrophic nitrification-aerobic denitrification (HNAD) pathway from carbon oxidation, nitrogen conversion, electron transport process, enzyme activity, as well as gene expression while sodium succinate, sodium citrate, and sodium acetate were utilized as the carbon sources. The nitrogen balance analysis results demonstrated that ZHL02 mainly removed NH4+-N through assimilation. The carbon source metabolism resulted in the discrepancies in electron transport chain and nitrogen removal between different HNAD bacteria. Moreover, the prokaryotic strand-specific transcriptome method showed that, amo and hao were absent in ZHL02, and unknown genes may be involved in ZHL02 during the HNAD process. As a fascinating process for removing nitrogen, the HNAD process is still puzzling, and the relationship between carbon metabolism and nitrogen metabolism among different HNAD pathways should be studied further.
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Affiliation(s)
- Jiyan Lu
- School of Civil Engineering, Changan University, Xian, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, China; Chang'an University, The Middle Section of the South 2nd Ring Road, 710064, Xian, Shaanxi Province, China
| | - Yue Tan
- School of Civil Engineering, Changan University, Xian, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, China; Chang'an University, The Middle Section of the South 2nd Ring Road, 710064, Xian, Shaanxi Province, China
| | - Shanghong Tian
- School of Civil Engineering, Changan University, Xian, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, China; Chang'an University, The Middle Section of the South 2nd Ring Road, 710064, Xian, Shaanxi Province, China
| | - Yuxiao Qin
- School of Civil Engineering, Changan University, Xian, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, China; Chang'an University, The Middle Section of the South 2nd Ring Road, 710064, Xian, Shaanxi Province, China
| | - Meng Zhou
- School of Civil Engineering, Changan University, Xian, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, China; Chang'an University, The Middle Section of the South 2nd Ring Road, 710064, Xian, Shaanxi Province, China
| | - Hao Hu
- School of Civil Engineering, Changan University, Xian, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, China; Chang'an University, The Middle Section of the South 2nd Ring Road, 710064, Xian, Shaanxi Province, China
| | - Xiaohong Zhao
- School of Civil Engineering, Changan University, Xian, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, China; Chang'an University, The Middle Section of the South 2nd Ring Road, 710064, Xian, Shaanxi Province, China
| | - Zhoufeng Wang
- School of Water and Environment, Changan University, Xian, China; Chang'an University, The Middle Section of the South 2nd Ring Road, 710064, Xian, Shaanxi Province, China.
| | - Bo Hu
- School of Civil Engineering, Changan University, Xian, China; Key Laboratory of Water Supply & Sewage Engineering, Ministry of Housing and Urban-rural Development, China; Chang'an University, The Middle Section of the South 2nd Ring Road, 710064, Xian, Shaanxi Province, China.
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Sun L, Yue X, Zhang G, Wang A. A pilot-scale anoxic-anaerobic-anoxic-oxic combined with moving bed biofilm reactor system for advanced treatment of rural wastewater. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 933:173074. [PMID: 38734101 DOI: 10.1016/j.scitotenv.2024.173074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 04/27/2024] [Accepted: 05/06/2024] [Indexed: 05/13/2024]
Abstract
Rural domestic poses a significant challenge to treatment technologies due to significant fluctuations in both water quality, particularly in terms of carbon concentration, and quantity. Conventional biological technology, such as anaerobic-anoxic-oxic (A2O) systems, is inefficient. In this work, a continuous pilot-scale anoxic-anaerobic-anoxic-oxic (A3O) reactor with a moving bed biofilm reactor (MBBR) system was constructed and optimized to improve the treatment efficiency of rural domestic wastewater. The sludge return ratio, volume ratio of the oxic-to-anoxic zone (Voxi/Vano), step-feeding and hydraulic retention time (HRT) at low temperature were considered the main parameters for optimization. Microbial analysis was performed on both the mixed liquor and carrier of the A3O-MBBR system under initial and post-optimized conditions. The results indicated that the A3O-MBBR improved the treatment efficiency of rural domestic wastewater, especially for total phosphorus (TP), which increased by 20 % compared with that of the A2O-MBR. In addition, the removal efficiencies of nitrogen and phosphorus were further optimized, and the average concentrations of total nitrogen (TN) and TP in the effluent reached 2.46 and 0.364 mg/L, respectively, at a sludge reflux ratio of 100 or 150 %, Voxi/Vano =200 %, step-feeding of 0.5Q/0.5Q (anaerobic/anoxic) and HRT of 15 h at low temperature in the A3O-MBBR, which met standard A of GB18918-2002, China (TN < 15 mg/L, TP < 0.5 mg/L). The average rate of attaining the standard increased by 58.63 % (post optimization). The microbial analysis showed an increase in species diversity and richness after the parameters were optimized. Moreover, compared to the microbial community structure before optimization, the post-optimization exhibited a more stable microbial structure with a significant enrichment of functional bacteria. Defluviimonas, Novosphingobium and Bifidobacterium, considered as the dominant nitrification or denitrifying bacteria, were enriched in the suspended sludge of the MBBR reactor, which the relative abundance increased by 3.11 %, 3.84 %, and 3.24 %, respectively. Further analysis of the microbial community in the carrier revealed that the abundance of Nitrospira and the denitrifying bacteria carried by the carrier were much greater than those in the suspended sludge. Consequently, the microorganism cooperation between suspended sludge and biofilm might be responsible for the improved performance of the optimized A3O-MBBR.
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Affiliation(s)
- Li Sun
- School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin 300401, China
| | - Xinbo Yue
- School of Intelligent Manufacturing Technology, Nanyang Vocational College, Xixia 474550, China
| | - Guangming Zhang
- School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin 300401, China.
| | - Aijie Wang
- Key Laboratory of Environmental Biotechnology, Chinese Academy of Sciences, Beijing 100085, China.
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Zhou Q, Jia L, Li Y, Wu W, Wang J. Significantly Enhanced Nitrate and Phosphorus Removal by Pyrite/Sawdust Composite-Driven Mixotrophic Denitrification with Boosted Electron Transfer: Comprehensive Evaluation of Water-Gas-Biofilm Phases during a Long-Term Study. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:10149-10161. [PMID: 38808456 DOI: 10.1021/acs.est.4c03677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
Further reducing total nitrogen (TN) and total phosphorus (TP) in the secondary effluent needs to be realized effectively and in an eco-friendly manner. Herein, four pyrite/sawdust composite-based biofilters were established to treat simulated secondary effluent for 304 days. The results demonstrated that effluent TN and TP concentrations from biofilters under the optimal hydraulic retention time (HRT) of 3.5 h were stable at <2.0 and 0.1 mg/L, respectively, and no significant differences were observed between inoculated sludge sources. The pyrite/sawdust composite-based biofilters had low N2O, CH4, and CO2 emissions, and the effluent's DOM was mainly composed of five fluorescence components. Moreover, mixotrophic denitrifiers (Thiothrix) and sulfate-reducing bacteria (Desulfosporosinus) contributing to microbial nitrogen and sulfur cycles were enriched in the biofilm. Co-occurrence network analysis deciphered that Chlorobaculum and Desulfobacterales were key genera, which formed an obvious sulfur cycle process that strengthened the denitrification capacity. The higher abundances of genes encoding extracellular electron transport (EET) chains/mediators revealed that pyrite not only functioned as an electron conduit to stimulate direct interspecies electron transfer by flagella but also facilitated EET-associated enzymes for denitrification. This study comprehensively evaluates the water-gas-biofilm phases of pyrite/sawdust composite-based biofilters during a long-term study, providing an in-depth understanding of boosted electron transfer in pyrite-based mixotrophic denitrification systems.
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Affiliation(s)
- Qi Zhou
- Department of Environmental Science, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
- Laboratory of Environmental Technology, INET, Tsinghua University, Beijing 100084, China
| | - Lixia Jia
- Department of Environmental Science, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Yuanwei Li
- Department of Environmental Science, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Weizhong Wu
- Department of Environmental Science, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Jianlong Wang
- Laboratory of Environmental Technology, INET, Tsinghua University, Beijing 100084, China
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Xie Y, Zhang Q, Wu Q, Zhang J, Dzakpasu M, Wang XC. Novel adaptive activated sludge process leverages flow fluctuations for simultaneous nitrification and denitrification in rural sewage treatment. WATER RESEARCH 2024; 255:121535. [PMID: 38564890 DOI: 10.1016/j.watres.2024.121535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Revised: 03/24/2024] [Accepted: 03/26/2024] [Indexed: 04/04/2024]
Abstract
The fluctuating characteristics of rural sewage flow pose a significant challenge for wastewater treatment plants, leading to poor effluent quality. This study establishes a novel adaptive activated sludge (AAS) process specifically designed to address this challenge. By dynamically adjusting to fluctuating water flow in situ, the AAS maintains system stability and promotes efficient pollutant removal. The core strategy of AAS leverages the inherent dissolved oxygen (DO) variations caused by flow fluctuations to establish an alternating anoxic-aerobic environment within the system. This alternating operation mode fosters the growth of aerobic denitrifiers, enabling the simultaneous nitrification and denitrification (SND) process. Over a 284-day operational period, the AAS achieved consistently high removal efficiencies, reaching 94 % for COD and 62.8 % for TN. Metagenomics sequencing revealed HN-AD bacteria as the dominant population, with the characteristic nap gene exhibiting a high relative abundance of 0.008 %, 0.010 %, 0.014 %, and 0.015 % in the anaerobic, anoxic, dynamic, and oxic zones, respectively. Overall, the AAS process demonstrates efficient pollutant removal and low-carbon treatment of rural sewage by transforming the disadvantage of flow fluctuation into an advantage for robust DO regulation. Thus, AAS offers a promising model for SND in rural sewage treatment.
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Affiliation(s)
- Yadong Xie
- Key Lab of Northwest Water Resource, Environment, and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an, 710055 China
| | - Qionghua Zhang
- Key Lab of Northwest Water Resource, Environment, and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an, 710055 China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Xi'an, 710055 China.
| | - Qi Wu
- Key Lab of Northwest Water Resource, Environment, and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an, 710055 China
| | - Jiyu Zhang
- Key Lab of Northwest Water Resource, Environment, and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an, 710055 China
| | - Mawuli Dzakpasu
- International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Xi'an, 710055 China; School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Xiaochang C Wang
- Key Lab of Northwest Water Resource, Environment, and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an, 710055 China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Xi'an, 710055 China
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Wang Z, Liao Y, Yan L, Liao B. Biological performance and membrane fouling of a microalgal-bacterial membrane photobioreactor for wastewater treatment without external aeration and carbonation. ENVIRONMENTAL RESEARCH 2024; 247:118272. [PMID: 38246292 DOI: 10.1016/j.envres.2024.118272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 01/10/2024] [Accepted: 01/18/2024] [Indexed: 01/23/2024]
Abstract
Biological nutrient removal processes involving the use of activated sludge (AS) to treat municipal wastewater normally result in high aeration energy consumption and significant greenhouse gas (GHG) emissions. Therefore, developing cost-efficient and environmentally friendly processes for wastewater treatment is vital. In this work, a novel non-aerated microalgal-bacterial membrane photobioreactor (MB-MPBR) was proposed, and its feasibility for organic contaminant and nutrient removals was evaluated, for the first time. The effects of inoculation ratio (microalgae to bacteria (M/B)) on the biological performance and membrane fouling were systematically investigated. The results showed that 95.9% of the chemical oxygen demand (COD), 74.5% of total nitrogen (TN), 98.5% of NH4+-N and 42.0% of total phosphorus (TP) were removed at an inoculation M/B ratio of 3:2 at steady state, representing a significant improvement compared to the M/B inoculation ratio of 1:3. Additionally, the higher inoculation M/B ratio (3:2) significantly promoted the biomass production owing to the favorable mutual exchange of oxygen and carbon dioxide between microalgae and bacteria. Cake layer formation was the primary fouling mechanism owing to the absence of aeration scouring on the membrane surface. The membrane fouling rate was slightly higher at the higher inoculation ratio (M/B = 3:2) owing to the increased biomass and extracellular polymeric substances (EPS) productions, despite the larger particle size. These results demonstrated that the non-aerated MB-MPBR could achieve superior biological performance, of which the inoculation M/B ratio was of critical importance for the initiation and maintenance of microalgal-bacterial symbiotic system, yet possibly caused severer membrane fouling in the absence of external aeration and carbonation. This study provides a new perspective for further optimizing and applying non-aerated MB-MPBR to enhance municipal wastewater treatment.
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Affiliation(s)
- Zhaozhao Wang
- College of Civil and Architectural Engineering, North China University of Science and Technology, Tangshan, 063210, PR China; College of Energy and Environmental Engineering, Hebei University of Engineering, Handan, 056038, PR China; Department of Chemical Engineering, Lakehead University, 955 Oliver Road, Thunder Bay, ON, P7B 5E1, Canada.
| | - Yichen Liao
- Department of Chemical Engineering, Lakehead University, 955 Oliver Road, Thunder Bay, ON, P7B 5E1, Canada
| | - Lina Yan
- College of Chemical Engineering, North China University of Science and Technology, Tangshan, 063210, PR China
| | - Baoqiang Liao
- Department of Chemical Engineering, Lakehead University, 955 Oliver Road, Thunder Bay, ON, P7B 5E1, Canada.
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