1
|
Zhang G, Hao Q, Xu S, Li Y, Zhang W, Liang Z, Jiang C. Optimizing nitrogen removal in constructed wetlands for low C/N ratio wastewater treatment: Insights from fermentation liquid utilization. WATER RESEARCH 2024; 262:122124. [PMID: 39053209 DOI: 10.1016/j.watres.2024.122124] [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: 06/05/2024] [Revised: 07/13/2024] [Accepted: 07/20/2024] [Indexed: 07/27/2024]
Abstract
The inefficient nitrogen removal in constructed wetlands (CWs) can be attributed to insufficient carbon sources for low carbon-to-nitrogen (C/N) ratio wastewater. In this study, sugarcane bagasse fermentation liquid (SBFL) was used as a supplemental carbon source in intermittently aerated CWs to enhance nitrogen removal. The impact of different regulated influent C/N ratios on nitrogen removal and greenhouse gas (GHG) emissions was investigated. Results demonstrated that SBFL addition significantly enhanced the denitrification capacity, resulting in faster NO3--N removal compared to sucrose. Moreover, intermittently aerated CWs significantly improved NH4+-N removal efficiency compared to non-aerated CWs. The highest total nitrogen removal efficiency (98.3 %) was achieved at an influent C/N ratio of 5 in intermittently aerated CWs with SBFL addition. The addition of SBFL resulted in a reduction of N2O emissions by 17.8 %-43.7 % compared to sucrose. All CWs exhibited low CH4 emissions, with SBFL addition (0.035-0.066 mg·m-2h-1) resulting in lower emissions compared to sucrose. Additionally, higher abundance of denitrification (nirK, nirS and nosZ) genes as well as more abundant denitrifying bacteria were shown in CWs of SBFL inputs. The results of this study provide a feasible strategy for applying SBFL as a carbon source to improve nitrogen removal efficiency and mitigate GHG emissions in CWs.
Collapse
Affiliation(s)
- Guosheng Zhang
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Qingju Hao
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China; Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Shiwen Xu
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Yanxun Li
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Wenxiao Zhang
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Zhenghao Liang
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Changsheng Jiang
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China; Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400715, China.
| |
Collapse
|
2
|
He Y, He Y, Abdullah Al-Dhabi N, Gao P, Huang H, Yan B, Cui X, Tang W, Zhang J, Lu Y, Peng F. Effects of exogenous thermophilic bacteria and ripening agent on greenhouse gas emissions, enzyme activity and microbial community during straw composting. BIORESOURCE TECHNOLOGY 2024; 407:131114. [PMID: 39009049 DOI: 10.1016/j.biortech.2024.131114] [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: 02/28/2024] [Revised: 07/12/2024] [Accepted: 07/12/2024] [Indexed: 07/17/2024]
Abstract
This research examined the impact of exogenous thermophilic bacteria and ripening agents on greenhouse gas (GHG) emission, enzyme activity, and microbial community during composting. The use of ripening agents alone resulted in a 30.9 % reduction in CO2 emissions, while the use of ripening agents and thermophilic bacteria resulted in a 50.8 % reduction in N2O emissions. Pearson's analysis showed that organic matter and nitrate nitrogen were the key parameters affecting GHG emissions. There was an inverse correlation between CO2 and CH4 releases and methane monooxygenase α subunit and N2O reductase activity (P<0.05). Additionally, N2O emissions were positively related to β-1, 4-N-acetylglucosaminidase, and ammonia monooxygenase activity (P<0.05). Deinococcota, Chloroflexi, and Bacteroidota are closely related to CO2 and N2O emissions. Overall, adding thermophilic bacteria represents an effective strategy to mitigate GHG emissions during composting.
Collapse
Affiliation(s)
- Yuewei He
- Institute of Agro-Environment and Ecology, Hunan Academy of Agricultural Sciences, Changsha, Hunan, 410125, China; College of Environment and Ecology, Hunan Agricultural University, Changsha 410128, Hunan, China
| | - Yuedong He
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, 410128, Hunan, China
| | - Naif Abdullah Al-Dhabi
- Department of Botany and Microbiology, College of Science, King Saud University, P. O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Peng Gao
- Institute of Agro-Environment and Ecology, Hunan Academy of Agricultural Sciences, Changsha, Hunan, 410125, China
| | - Hongli Huang
- College of Environment and Ecology, Hunan Agricultural University, Changsha 410128, Hunan, China
| | - Binghua Yan
- College of Environment and Ecology, Hunan Agricultural University, Changsha 410128, Hunan, China
| | - Xinwei Cui
- Institute of Agro-Environment and Ecology, Hunan Academy of Agricultural Sciences, Changsha, Hunan, 410125, China.
| | - Wangwang Tang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China
| | - Jiachao Zhang
- College of Environment and Ecology, Hunan Agricultural University, Changsha 410128, Hunan, China
| | - Yaoxiong Lu
- Institute of Agro-Environment and Ecology, Hunan Academy of Agricultural Sciences, Changsha, Hunan, 410125, China
| | - Fuyuan Peng
- Institute of Agro-Environment and Ecology, Hunan Academy of Agricultural Sciences, Changsha, Hunan, 410125, China
| |
Collapse
|
3
|
Liu Z, Feng L, Liu C. Effect of bacteria-algae ratio on treatment of anaerobic digested wastewater by symbiotic coupling of bacteria and algae under the background of carbon neutralization. ENVIRONMENTAL RESEARCH 2024; 251:118771. [PMID: 38522745 DOI: 10.1016/j.envres.2024.118771] [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: 11/14/2023] [Revised: 03/04/2024] [Accepted: 03/20/2024] [Indexed: 03/26/2024]
Abstract
Environmental pollution is a growing concern, particularly the impact of sewage treatment gas on the atmosphere's greenhouse effect. Efficient sewage resource recycling is crucial to achieving carbon neutrality. The bacteria-algae symbiotic sewage treatment system combines wastewater treatment, carbon dioxide fixation, and biomass energy recovery to achieve the goal of carbon neutrality, environmental protection, and the transformation of high-value added products. This paper presents the construction of a sequencing batch photobiological reaction system that utilizes a microbial-algae symbiotic relationship. The system was used to analyze the degradation effects of sCOD, TN, AN, and TP in anaerobic digestion wastewater by varying the microbial-algae ratios. Additionally, changes in the microbial community were analyzed to explore the system's potential for reducing carbon emissions. The study's findings indicate that: 1)When the ratio of bacteria to algae was 2:3, the removal rates of TN, AN, sCOD, and TP were 81.38%, 94.28%, 75.33%, and 96.56%. 2)Changing the ratio of bacteria to algae would affect the bacterial concentration in the mixed system, but not the bacterial community structure. The results indicate that a ratio of 2:3 enhances the removal of pollutants by bacteria and algae symbionts.3) Under the context of carbon neutralization, this paper investigates the reduction of carbon emissions in ADE treated by bacteria-algae symbiosis at the optimal bacteria to algae ratio. The experimental process can reduce 177.03 mg CO2 compared to complete nutrient consumption treatment, which is equivalent to a reduction of 355.08 g CO2 per 1 m3 of ADE. For full anaerobic treatment, this experimental process can reduce 228.35 mg of CO2 equivalent CH4, which translates to a reduction of 456.71 g of CO2 equivalent CH4 per 1 m3 of ADE.
Collapse
Affiliation(s)
- Zhipeng Liu
- School of Energy and Environment, Shenyang Aerospace University, Shenyang, 110136, China
| | - Lei Feng
- School of Energy and Environment, Shenyang Aerospace University, Shenyang, 110136, China.
| | - Chenxi Liu
- School of Energy and Environment, Shenyang Aerospace University, Shenyang, 110136, China
| |
Collapse
|
4
|
Feng R, Li Z, Qi Z. China's anthropogenic N 2O emissions with analysis of economic costs and social benefits from reductions in 2022. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 353:120234. [PMID: 38308993 DOI: 10.1016/j.jenvman.2024.120234] [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: 11/21/2023] [Revised: 01/24/2024] [Accepted: 01/24/2024] [Indexed: 02/05/2024]
Abstract
We assess China's overall anthropogenic N2O emissions via the official guidebook published by Chinese government. Results show that China's overall anthropogenic N2O emissions in 2022 were around 1593.1 (1508.7-1680.7) GgN, about 47.0 %, 27.0 %, 13.4 %, 4.9 %, and 7.7 % of which were caused by agriculture, industry, energy utilization, wastewater, and indirect sources, respectively. Maximum reduction rate for N2O emissions from agriculture, industry, energy utilization, wastewater, and indirect sources can achieve 69 %, 99 %, 79 %, 86 %, and 48 %, respectively, in 2022. However, given current global scenarios with a rapidly changing population and geopolitical and energy tension, the emission reduction may not be fully fulfilled. Without compromising yields, China's theoretical minimum anthropogenic N2O emissions would be 600.6 (568.8-633.6) GgN. In terms of the economic costs for reducing one kg of N2O-N emissions, the price ranged from €12.9 to €81.1 for agriculture, from €0.08 to €0.16 for industry, and from €104.8 to €1571.5 for energy utilization. We acknowledge the emission reduction rates may not be completely realistic for large-scale application in China. The social benefits gained from reducing one kg of N2O-N emissions in China was about €5.2, indicating anthropogenic N2O emissions caused a loss 0.03 % of China's GDP, but only justifying reduction in industrial N2O emissions from the economic perspective. We perceive that the present monetized values will be trustworthy for at least three to five years, but later the numerical monetized values need to be considered in inflation and other currency-dependent conditions.
Collapse
Affiliation(s)
- Rui Feng
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China; State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, 310027, China.
| | - Zhenhua Li
- Xiacheng District Study-Aid Science & Technology Studio, Hangzhou, 310004, China
| | - Zhuangzhou Qi
- School of Economics and Management, University of Chinese Academy of Sciences, Beijing, 100190, China.
| |
Collapse
|