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Chen J, Wang H, Yin W, Wang Y, Lv J, Wang A. Deciphering carbon emissions in urban sewer networks: Bridging urban sewer networks with city-wide environmental dynamics. WATER RESEARCH 2024; 256:121576. [PMID: 38608619 DOI: 10.1016/j.watres.2024.121576] [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: 12/08/2023] [Revised: 03/26/2024] [Accepted: 04/05/2024] [Indexed: 04/14/2024]
Abstract
As urbanization accelerates, understanding and managing carbon emissions from urban sewer networks have become crucial for sustainable urban water cycles. This review examines the factors influencing greenhouse gas (GHG) emissions within urban sewage systems, analyzing the complex effects between water quality, hydrodynamics, and sewer infrastructure on GHG production and emission processes. It reveals significant spatiotemporal heterogeneity in GHG emissions, particularly under long-term scenarios where flow rates and temperatures exhibit strong impacts and correlations. Given the presence of fugitive and dissolved potential GHGs, standardized monitoring and accounting methods are deemed essential. Advanced modeling techniques emerge as crucial tools for large-scale carbon emission prediction and management. The review identifies that traditional definitions and computational frameworks for carbon emission boundaries fail to fully consider the inherent heterogeneity of sewers and the dynamic changes and impacts of multi-source pollution within the sewer system during the urban water cycle. This includes irregular fugitive emissions, the influence of stormwater systems, climate change, geographical features, sewer design, and the impacts of food waste and antibiotics. Key strategies for emission management are discussed, focusing on the need for careful consideration of approaches that might inadvertently increase global emissions, such as ventilation, chemical treatments, and water management practices. The review advocates for an overarching strategy that encompasses a holistic view of carbon emissions, stressing the importance of refined emission boundary definitions, novel accounting practices, and comprehensive management schemes in line with the water treatment sector's move towards carbon neutrality. It champions the adoption of interdisciplinary, technologically advanced solutions to mitigate pollution and reduce carbon emissions, emphasizing the importance of integrating cross-scale issues and other environmentally friendly measures in future research directions.
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Affiliation(s)
- Jiaji Chen
- Key Lab of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing 100085, China; Sino-Danish College, University of Chinese Academy of Sciences, Beijing 101408, China; State Key Laboratory of Urban Water Resource and Environment, School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen 518055, China; Sino-Danish Center for Education and Research, University of Chinese Academy of Sciences, Beijing 101408, China
| | - Hongcheng Wang
- State Key Laboratory of Urban Water Resource and Environment, School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen 518055, China.
| | - Wanxin Yin
- College of the Environment, Liaoning University, Shenyang 110036, China
| | - Yuqi Wang
- State Key Laboratory of Urban Water Resource and Environment, School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen 518055, China
| | - Jiaqiang Lv
- State Key Laboratory of Urban Water Resource and Environment, School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen 518055, China; State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - AiJie Wang
- Key Lab of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Haidian District, Beijing 100085, China; State Key Laboratory of Urban Water Resource and Environment, School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen 518055, China.
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Ren Z, Li D, Zhang Z, Sun W, Liu G. Enhancing the relative abundance of comammox nitrospira in ammonia oxidizer community decreases N 2O emission in nitrification exponentially. CHEMOSPHERE 2024; 356:141883. [PMID: 38583528 DOI: 10.1016/j.chemosphere.2024.141883] [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: 01/13/2024] [Revised: 03/28/2024] [Accepted: 04/01/2024] [Indexed: 04/09/2024]
Abstract
Comammox Nitrospira and canonical ammonia-oxidizing bacteria (cAOB) generally coexist in activated sludge. In present study, the effect of comammox Nitrospira on N2O production during nitrification of activated sludge was investigated. Comammox Nitrospira and cAOB were separately enriched in two nitrifying reactors, with respective relative abundance of approximately 98% in ammonia oxidizer community. The N2O emission factor (EF) of nitrification in comammox Nitrospira dominated reactor was 0.35%, consistently lower than that (2.2%) in cAOB dominated reactor. When increasing the relative abundance of comammox Nitrospira in ammonia oxidizer community, the N2O EF of nitrification decreased exponentially, which suggested that comammox Nitrospira not only decreased N2O production directly but also might have reduced N2O yield by cAOB. When cAOB dominated the ammonia oxidizer community of sludge, decreasing pH to 6.3, lowering DO to less than 0.5 mg/L, and increasing nitrite concentration enhanced N2O EF dramatically. When comammox Nitrospira became the dominant ammonia oxidizer, however, the N2O EF correlated to nitrite insignificantly and a low DO of 0.2 mg/L and weakly acidic pH (6.3) decreased N2O EF by approximately 70% and 60%, respectively. These results imply that enhancing the relative abundance of comammox Nitrospira in sludge is an effective way to reducing N2O emissions and can also offset the promoting effects of acidic pH, low DO, and high nitrite concentration on N2O production during nitrification.
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Affiliation(s)
- Zhichang Ren
- Guangdong Engineering Research Center of Water Treatment Processes and Materials, Guangdong Key Laboratory of Environmental Pollution and Health, and School of Environment, Jinan University, Guangzhou 510632, And Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000, China
| | - Deyong Li
- Guangdong Engineering Research Center of Water Treatment Processes and Materials, Guangdong Key Laboratory of Environmental Pollution and Health, and School of Environment, Jinan University, Guangzhou 510632, And Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000, China
| | - Zhuang Zhang
- Guangdong Engineering Research Center of Water Treatment Processes and Materials, Guangdong Key Laboratory of Environmental Pollution and Health, and School of Environment, Jinan University, Guangzhou 510632, And Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000, China
| | - Weimin Sun
- Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou, 510650, China
| | - Guoqiang Liu
- Guangdong Engineering Research Center of Water Treatment Processes and Materials, Guangdong Key Laboratory of Environmental Pollution and Health, and School of Environment, Jinan University, Guangzhou 510632, And Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000, China.
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Sierra A, Correia C, Ortega T, Forja J, Rodrigues M, Cravo A. Dynamics of CO 2, CH 4, and N 2O in Ria Formosa coastal lagoon (southwestern Iberia) and export to the Gulf of Cadiz. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167094. [PMID: 37734615 DOI: 10.1016/j.scitotenv.2023.167094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 08/16/2023] [Accepted: 09/13/2023] [Indexed: 09/23/2023]
Abstract
A first characterization of greenhouse gases had been carried out to study their role and impact in a productive transitional coastal system of the southern Portugal - Ria Formosa lagoon. To this purpose, the partial pressure of CO2 (pCO2) and the concentration of dissolved CH4 and N2O have been measured. Two surveys were carried out during 2020, at low tide under typical conditions of Spring (March) and end of Summer (October). The samplings sites were distributed along the costal lagoon covering: i) inner areas with strong human impact (influence of different flows of treated wastewater discharges); and ii) main channels in connection with the main inlets to study the exchanges with the ocean. In general, the highest values of the three greenhouse gases were found at the inner studied areas, especially affected by the disposal of treated effluents from wastewater treatment plans, in October. The mean water - atmosphere fluxes of the CO2, CH4 and N2O are positive, showing that the study area acts as a source of these gases to the atmosphere. On the other hand, it was calculated a rough estimation of the three gases globally exported from Ria Formosa to the ocean, through the main six inlets to evaluate the magnitude of the supply of these gases from Ria Formosa to the adjacent ocean. The mean CO2, CH4 and N2O horizontal water fluxes exported from all the inlets of Ria Formosa to the Gulf of Cadiz for both seasons, during low water, are 8.7 ± 3.9 mmol m-2 s-1, 8.0 ± 3.5 μmol m-2 s-1 and 3.2 ± 1.5 μmol m-2 s-1, which corresponds to a mass transport through the inlets section of 0.7 ± 0.7 kg s-1, 0.2 ± 0.2 g s-1 and 0.2 ± 0.3 g s-1 respectively. From these estimates, as expected, the higher mass transport was found at the larger and deeper inlets (Faro-Olhão and Armona).
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Affiliation(s)
- A Sierra
- Dpto. Química-Física, INMAR, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, Campus Universitario Río San Pedro, 11510 Puerto Real, Cádiz, Andalucía, Spain.
| | - C Correia
- FCT, CIMA, Centre of Marine and Environmental Research\ARNET - Infrastructure Network in Aquatic Research, University of Algarve, Campus de Gambelas, 8000-139 Faro, Portugal.
| | - T Ortega
- Dpto. Química-Física, INMAR, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, Campus Universitario Río San Pedro, 11510 Puerto Real, Cádiz, Andalucía, Spain.
| | - J Forja
- Dpto. Química-Física, INMAR, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, Campus Universitario Río San Pedro, 11510 Puerto Real, Cádiz, Andalucía, Spain.
| | - M Rodrigues
- Laboratório Nacional de Engenharia Civil, Avenida do Brasil, 101, 1700-066 Lisboa, Portugal.
| | - A Cravo
- FCT, CIMA, Centre of Marine and Environmental Research\ARNET - Infrastructure Network in Aquatic Research, University of Algarve, Campus de Gambelas, 8000-139 Faro, Portugal.
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Zhang G, Pang Y, Zhou Y, Zhang Y, Zhu DZ. Effect of dissolved oxygen on N 2O release in the sewer system during controlling hydrogen sulfide by nitrate dosing. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 816:151581. [PMID: 34774952 DOI: 10.1016/j.scitotenv.2021.151581] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/03/2021] [Accepted: 11/06/2021] [Indexed: 06/13/2023]
Abstract
Nitrate dosing is commonly used for controlling hydrogen sulfide in sewer systems. However, it may potentially facilitate N2O emission due to the denitrification process promoted by nitrate addition. In this study, lab-scale sewer reactors were operated to investigate the impact of nitrate addition on N2O production in sewer systems. Results showed that the N2O flux even increased by six times with the addition of nitrate when dissolved oxygen (DO) in the wastewater exceeded 0.4 mg/L. Principal component analysis showed that the N2O concentration was notably affected by DO and oxidation-reduction potential (ORP) in the wastewater. Furthermore, it was founded that N2O flux had a strong linear relationship with the DO concentration in the batch test. The microbial analysis found that the nosZ possessing organisms decreased significantly in the micro-aerobic condition and the copy numbers of nosZ gene declined consequently. It indicated that the inhibition of N2O reduced to N2 was responsible for significant accumulation and emission of N2O in the micro-aerobic condition. Given the gravity sewers are not completely anaerobic, the DO concentration is ranged from 0.1 to 2.4 mg/L in gravity sewers with the partially filled flow. Therefore, more attention should be paid to the N2O production when nitrate dosing for hydrogen sulfide controlling in gravity sewers.
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Affiliation(s)
- Guijiao Zhang
- College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, 310058, China
| | - Yao Pang
- College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, 310058, China
| | - Yongchao Zhou
- College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, 310058, China.
| | - Yiping Zhang
- College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, 310058, China
| | - David Z Zhu
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, AB T6G 2W2, Canada
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Domingo-Félez C, Smets BF. Regulation of key N2O production mechanisms during biological water treatment. Curr Opin Biotechnol 2019; 57:119-126. [DOI: 10.1016/j.copbio.2019.03.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 01/11/2019] [Accepted: 03/05/2019] [Indexed: 11/26/2022]
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Analysis of Greenhouse Gas Emissions in Centralized and Decentralized Water Reclamation with Resource Recovery Strategies in Leh Town, Ladakh, India, and Potential for Their Reduction in Context of the Water–Energy–Food Nexus. WATER 2019. [DOI: 10.3390/w11050906] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
With the constant increase of population and urbanization worldwide, stress on water, energy, and food resources is growing. Climate change constitutes a source of vulnerability, raising the importance of implementing actions to mitigate it. Within this, the water and wastewater sector represents an important source of greenhouse gas (GHG) emissions, during both the construction and operation phase. The scope of this study is to analyze the GHG emissions from the current and future water supply scheme, as well as to draw a comparison between possible water reclamation with resource recovery scenarios in the town Leh in India: a centralized scheme, a partly centralized combined with a decentralized scheme, and a household level approach. Precise values of emission factors, based on the IPCC Guidelines for National Greenhouse Gas Inventories, previous studies, and Ecoinvent database, have been adopted to quantify the different emissions. Potential sources of reduction of GHG emissions through sludge and biogas utilization have been identified and quantified to seize their ability to mitigate the carbon footprint of the water and wastewater sector. The results show that the future water supply scheme will lead to a significant increase of the GHG emissions during its operation. Further, it is shown that decentralizing wastewater management in Leh town has the least carbon footprint during both construction and operation phases. These results have implications for cities worldwide.
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Bojorquez Carrillo M, Herrera EF, Navarro CJ, Tapia Padilla G. Correlation between meteorological parameters and nitrogen compounds present in wastewater in the formation of nitrous oxide in soils. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION (1995) 2018; 68:1357-1365. [PMID: 30118630 DOI: 10.1080/10962247.2018.1511488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 07/29/2018] [Accepted: 08/09/2018] [Indexed: 06/08/2023]
Abstract
In the present work, nitrous oxide emissions were estimated [mg/L] by the use of lysimeters under the closed chamber technique for a six month period. The lysimeters were classified by the type of irrigation used: one for drinking water, and the other for treated wastewater. Each lysimeter had two different types of soil (sand and clay), based on the types of soil in Chihuahua City, Mexico. An additional classification based on the depth was done (reticular and vadose zone). Each zone collected gas by the use of a closed chamber technique, allowing the samples to be taken for subsequent quantification and analysis by gas chromatography. A statistical analysis of variance (ANOVA) and principal components analysis (PCA) were conducted to identify the most influential variables or parameters in the formation of nitrous oxide. The variables that were considered for analysis were total Kjeldahl nitrogen (TKN), ammoniacal nitrogen (NH3-N), nitrate nitrogen (NO3-N), and nitrite nitrogen (NO2-N), along with meteorological parameters. In total, 58944 mg/L of N2O were emitted during the measurement period. The results showed that concentration emissions of N2O where the type of soil is sandy were smaller than those of clay soil, while the mean concentration in the vadose zone was higher than those in the reticular zone, regardless the type of soil. The parameters that showed greater influence in the N2O emissions were NO2-N and NO3-N concentrations. Temperature also played an important role in the emissions (the highest emissions were emitted during the cold months). Furthermore, denitrification appeared to be the dominant process in the production of nitrous oxide in soils. Implications: Nitrous oxide (N2O) emissions produced in lysimeters with two types of soil (sand and clay) at two different depths (vadose and reticular zones) using treated waste water showed that the higher emissions of N2O are derived from clay soils in vadose zone; it could be due to the formation of clogging that favors the formation of anoxic conditions for the denitrification process. The parameters that showed more influence in the N2O emissions were nitrite (NO2-N) and nitrate (NO3-N) concentrations along with the temperature.
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Affiliation(s)
- Martin Bojorquez Carrillo
- a Department of Environmental and Energy , Research Center of Advanced Materials S.C. (CIMAV) , Chih , Mexico
| | - Eduardo Florencio Herrera
- a Department of Environmental and Energy , Research Center of Advanced Materials S.C. (CIMAV) , Chih , Mexico
| | - Carmen Julia Navarro
- b Autonomous University of Chihuahua, Faculty of Engineering , University Campus Chihuahua , Chih , Mexico
| | - Gabriela Tapia Padilla
- c Department of Environmental and Energy , National Council for Science and Technology (CONACYT), Research Center of Advanced Materials S.C. (CIMAV) , Chih , Mexico
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Yu L, Li R, Delatolla R, Zhang R, Yang X, Peng D. Natural continuous influent nitrifier immigration effects on nitrification and the microbial community of activated sludge systems. J Environ Sci (China) 2018; 74:159-167. [PMID: 30340669 DOI: 10.1016/j.jes.2018.02.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 02/13/2018] [Accepted: 02/13/2018] [Indexed: 06/08/2023]
Abstract
Two sequencing batch reactors (SBRs) were operated for 100days under aerobic conditions, with one being fed with unsterilized municipal wastewater (USBR), and the other fed with sterilized municipal wastewater (SSBR). Respirometric assays and fluorescence in situ hybridization (FISH) results show that active nitrifiers were present in the unsterilized influent municipal wastewater. The maximum ammonia utilization rate (AUR) and nitrite utilization rate (NUR) of the unsterilized influent were 0.32±0.12mg NH4+-N/(L·hr) and 0.71±0.18mg NO2--N/(L·hr). Based on the maximum utilization rates, the estimated seeding intensity for the ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) of the USBR was 0.08g AOB/(g AOB·day) and 0.20g NOB/(g NOB·day) respectively. The fraction of nitrifiers/total bacteria in the influent was 5.35%±2.1%, the dominant AOB was Nitrosomonas spp., Nitrosococcus mobilis hybridizated with Nsm156, and the dominant NOB was Nitrospira hybridizated with Ntspa662. The influent nitrifiers potentially seeded the activated sludge of the bioreactor and hence demonstrated a mitigation of the acclimatization times and instability during start-up and early operation. The AUR and NUR in the USBR was 15% and 13% higher than the SSBR respectively during the stable stage, FISH results showed that nitrifiers population especially the Nitrospira in the USBR was higher than that in the SSBR. These results indicate that the natural continuous immigration of nitrifiers from municipal influent streams may have some repercussions on the modeling and design of bioreactors.
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Affiliation(s)
- Lifang Yu
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
| | - Ren Li
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Robert Delatolla
- Department of Civil Engineering, University of Ottawa, Ottawa, ON, Canada
| | - Ru Zhang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Xiuling Yang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Dangcong Peng
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
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Fries AE, Schifman LA, Shuster WD, Townsend-Small A. Street-level emissions of methane and nitrous oxide from the wastewater collection system in Cincinnati, Ohio. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 236:247-256. [PMID: 29414346 PMCID: PMC6537879 DOI: 10.1016/j.envpol.2018.01.076] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 01/20/2018] [Accepted: 01/22/2018] [Indexed: 06/08/2023]
Abstract
Recent studies have indicated that urban streets can be hotspots for emissions of methane (CH4) from leaky natural gas lines, particularly in cities with older natural gas distribution systems. The objective of the current study was to determine whether leaking sewer pipes could also be a source of street-level CH4 as well as nitrous oxide (N2O) in Cincinnati, Ohio, a city with a relatively new gas pipeline network. To do this, we measured the carbon (δ13C) and hydrogen (δ2H) stable isotopic composition of CH4 to distinguish between biogenic CH4 from sewer gas and thermogenic CH4 from leaking natural gas pipelines and measured CH4 and N2O flux rates and concentrations at sites from a previous study of street-level CH4 enhancements (77 out of 104 sites) as well as additional sites found through surveying sewer grates and utility manholes (27 out of 104 sites). The average isotopic signatures for δ13C-CH4 and δ2H-CH4 were -48.5‰ ± 6.0‰ and -302‰ ± 142‰. The measured flux rates ranged from 0.0 to 282.5 mg CH4 day-1 and 0.0-14.1 mg N2O day-1 (n = 43). The average CH4 and N2O concentrations measured in our study were 4.0 ± 7.6 ppm and 392 ± 158 ppb, respectively (n = 104). 72% of sites where fluxes were measured were a source of biogenic CH4. Overall, 47% of the sampled sites had biogenic CH4, while only 13% of our sites had solely thermogenic CH4. The other sites were either a source of both biogenic and thermogenic CH4 (13%), and a relatively large portion of sites had an unresolved source (29%). Overall, this survey of emissions across a large urban area indicates that production and emission of biogenic CH4 and N2O is considerable, although CH4 fluxes are lower than those reported for cities with leaky natural gas distribution systems.
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Affiliation(s)
- Anastasia E Fries
- Department of Geology, University of Cincinnati, 500 Geology-Physics Building, 345 Clifton Court, Cincinnati, OH, 45221, USA
| | - Laura A Schifman
- U.S. Environmental Protection Agency, National Risk Management Research Laboratory, 26 W. Martin Luther King Dr., Cincinnati, OH, 45268, USA
| | - William D Shuster
- U.S. Environmental Protection Agency, National Risk Management Research Laboratory, 26 W. Martin Luther King Dr., Cincinnati, OH, 45268, USA
| | - Amy Townsend-Small
- Department of Geology, University of Cincinnati, 500 Geology-Physics Building, 345 Clifton Court, Cincinnati, OH, 45221, USA.
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Masuda S, Sano I, Hojo T, Li YY, Nishimura O. The comparison of greenhouse gas emissions in sewage treatment plants with different treatment processes. CHEMOSPHERE 2018; 193:581-590. [PMID: 29169134 DOI: 10.1016/j.chemosphere.2017.11.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 10/31/2017] [Accepted: 11/04/2017] [Indexed: 06/07/2023]
Abstract
Greenhouse gas emissions from different sewage treatment plants: oxidation ditch process, double-circulated anoxic-oxic process and anoxic-oxic process were evaluated based on the survey. The methane and nitrous oxide characteristics were discussed based on the gaseous and dissolved gas profiles. As a result, it was found that methane was produced in the sewer pipes and the primary sedimentation tank. Additionally, a ventilation system would promote the gasification of dissolved methane in the first treatment units. Nitrous oxide was produced and emitted in oxic tanks with nitrite accumulation inside the sewage treatment plant. A certain amount of nitrous oxide was also discharged as dissolved gas through the effluent water. If the amount of dissolved nitrous oxide discharge is not included, 7-14% of total nitrous oxide emission would be overlooked. Based on the greenhouse gas calculation, electrical consumption and the N2O emission from incineration process were major sources in all the plants. For greenhouse gas reduction, oxidation ditch process has an advantage over the other advanced systems due to lower energy consumption, sludge production, and nitrogen removal without gas stripping.
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Affiliation(s)
- Shuhei Masuda
- Department of Civil Engineering and Architecture, National Institute of Technology, Akita College, Bunkyocho 1-1, Iijima, Akita, Japan.
| | - Itsumi Sano
- Department of Civil and Environmental Engineering, Tohoku University, Aoba 6-6-06, Aobayama, Aoba-ku, Sendai, Japan
| | - Toshimasa Hojo
- Department of Civil and Environmental Engineering, Tohoku University, Aoba 6-6-06, Aobayama, Aoba-ku, Sendai, Japan
| | - Yu-You Li
- Department of Civil and Environmental Engineering, Tohoku University, Aoba 6-6-06, Aobayama, Aoba-ku, Sendai, Japan
| | - Osamu Nishimura
- Department of Civil and Environmental Engineering, Tohoku University, Aoba 6-6-06, Aobayama, Aoba-ku, Sendai, Japan
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11
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Kosse P, Lübken M, Schmidt TC, Wichern M. Quantification of nitrous oxide in wastewater based on salt-induced stripping. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 601-602:83-88. [PMID: 28550728 DOI: 10.1016/j.scitotenv.2017.05.053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 05/03/2017] [Accepted: 05/05/2017] [Indexed: 06/07/2023]
Abstract
Monitoring nitrous oxide (N2O) emissions from wastewater treatment plants has attracted much attention in recent years demanding accurate and rapid quantification methods. In the present study a salt-assisted methodology is proposed by which N2O is chemically stripped out from wastewater and quantified by gas chromatography (GC-TCD) subsequently. Eight different inorganic salts have been evaluated for this purpose, likewise the application of ultrasound. By addition of sodium bromide (NaBr) the best recovery rate of about 98% (=1.14±0.05kg·m-3) N2O from a saturated stock solution (1.16kg·m-3, 295.85K and 1atm) was achieved. The application of ultrasound led to considerable smaller N2O recoveries of 37% (=0.43±0.01kg·m-3) after a 60min treatment. Practical applicability of the method has been demonstrated by applying NaBr to grab samples from a municipal wastewater treatment plant. The highest N2O concentration was found in the secondary clarifier with 10.99±0.20g·m-3. Besides, N2O could be quantified in the activated sludge process with up to 9.87±0.50g·m-3 yielding 7.75gN2O·PE-1·a-1 specifically for the investigated wastewater treatment plant. Hence, the proposed method proved suitable as a routine quantification method for N2O.
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Affiliation(s)
- Pascal Kosse
- Institute of Urban Water Management and Environmental Engineering, Ruhr-Universität Bochum, Universitätsstraße 150, 44780 Bochum, Germany.
| | - Manfred Lübken
- Institute of Urban Water Management and Environmental Engineering, Ruhr-Universität Bochum, Universitätsstraße 150, 44780 Bochum, Germany
| | - Torsten C Schmidt
- Instrumental Analytical Chemistry, University of Duisburg-Essen, Universitätsstraße 5, 45141 Essen, Germany; Centre for Water and Environmental Research (ZWU), University of Duisburg-Essen, Universitätsstraße 2, 45141 Essen, Germany
| | - Marc Wichern
- Institute of Urban Water Management and Environmental Engineering, Ruhr-Universität Bochum, Universitätsstraße 150, 44780 Bochum, Germany
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Short MD, Daikeler A, Wallis K, Peirson WL, Peters GM. Dissolved methane in the influent of three Australian wastewater treatment plants fed by gravity sewers. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 599-600:85-93. [PMID: 28472696 DOI: 10.1016/j.scitotenv.2017.04.152] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 04/19/2017] [Accepted: 04/20/2017] [Indexed: 06/07/2023]
Abstract
Methane (CH4) is an important anthropogenic greenhouse gas and a by-product of urban sewage management. In recent years and contrary to international (IPCC) consensus, pressurised (anaerobic) sewers were identified as important CH4 sources, yet relatively little remains known regarding the role of gravity sewers in CH4 production and conveyance. Here we provide the results of a nine month study assessing dissolved CH4 levels in the raw influent of three large Australian wastewater treatment plants (WWTPs) fed by gravity sewers. Similar to recent international research and contrary to IPCC guidance, results show that gravity sewered wastewater contains moderate levels of CH4 (≈1mgL-1). Dissolved CH4 concentration correlated negatively with daily sewage flow rate (i.e. inversely proportional to sewer hydraulic residence time), with daily CH4 mass loads on average some two-fold greater under low flow (dry weather) conditions. Along with sewage hydraulic residence time, sewer sediments are thought to interact with sewage flow rate and are considered to play a key role in gravity sewer CH4 production. A per capita load of 78gCH4person-1y-1 is offered for gravity sewered wastewater entering WWTPs, with a corresponding emission estimate of up to 62gCH4person-1y-1, assuming 80% water-to-air transfer of inflowing CH4 in WWTPs with combined preliminary-primary plus secondary treatment. Results here support the emerging consensus view that hydraulic operation (i.e. gravity versus pressurised, sewage flow rate) is a key factor in determining sewer CH4 production, with gravity sewer segments likely to play a dominant role in total CH4 production potential for large metropolitan sewer networks. Further work is warranted to assess the scale and temporal dynamics of CH4 production in gravity sewers elsewhere, with more work needed to adequately capture and assess the scale of diffuse sewer network CH4 emissions from sprawling urban settlements globally.
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Affiliation(s)
- Michael D Short
- School of Natural and Built Environments, University of South Australia, Mawson Lakes, South Australia 5095, Australia; Future Industries Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia; School of Civil and Environmental Engineering, The University of New South Wales, Sydney, New South Wales 2052, Australia.
| | - Alexander Daikeler
- School of Civil and Environmental Engineering, The University of New South Wales, Sydney, New South Wales 2052, Australia; Institute for Energy Systems and Technology, Technische Universität Darmstadt, 64289 Darmstadt, Germany
| | - Kirsten Wallis
- School of Civil and Environmental Engineering, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - William L Peirson
- School of Civil and Environmental Engineering, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Gregory M Peters
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
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Sun S, Bao Z, Li R, Sun D, Geng H, Huang X, Lin J, Zhang P, Ma R, Fang L, Zhang X, Zhao X. Reduction and prediction of N 2O emission from an Anoxic/Oxic wastewater treatment plant upon DO control and model simulation. BIORESOURCE TECHNOLOGY 2017; 244:800-809. [PMID: 28830043 DOI: 10.1016/j.biortech.2017.08.054] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 08/08/2017] [Accepted: 08/09/2017] [Indexed: 06/07/2023]
Abstract
In order to make a better understanding of the characteristics of N2O emission in A/O wastewater treatment plant, full-scale and pilot-scale experiments were carried out and a back propagation artificial neural network model based on the experimental data was constructed to make a precise prediction of N2O emission. Results showed that, N2O flux from different units followed a descending order: aerated grit tank>oxic zone≫anoxic zone>final clarifier>primary clarifier, but 99.4% of the total emission of N2O (1.60% of N-load) was monitored from the oxic zone due to its big surface area. A proper DO control could reduce N2O emission down to 0.21% of N-load in A/O process, and a two-hidden-layers back propagation model with an optimized structure of 4:3:9:1 could achieve a good simulation of N2O emission, which provided a new method for the prediction of N2O emission during wastewater treatment.
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Affiliation(s)
- Shichang Sun
- College of Chemistry and Enviromental Engineering, Shenzhen University, Shenzhen 518060, China; College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| | - Zhiyuan Bao
- Beijing Key Lab. for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing, China
| | - Ruoyu Li
- Beijing Key Lab. for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing, China
| | - Dezhi Sun
- Beijing Key Lab. for Source Control Technology of Water Pollution, Beijing Forestry University, Beijing, China
| | - Haihong Geng
- College of Chemistry and Enviromental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Xiaofei Huang
- College of Chemistry and Enviromental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Junhao Lin
- College of Chemistry and Enviromental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Peixin Zhang
- College of Chemistry and Enviromental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Rui Ma
- College of Chemistry and Enviromental Engineering, Shenzhen University, Shenzhen 518060, China.
| | - Lin Fang
- College of Chemistry and Enviromental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Xianghua Zhang
- College of Chemistry and Enviromental Engineering, Shenzhen University, Shenzhen 518060, China; Laboratory of Glasses and Ceramics, Institute of Chemical Science, University of Rennes 1, Rennes 35042, France
| | - Xuxin Zhao
- College of Chemistry and Enviromental Engineering, Shenzhen University, Shenzhen 518060, China
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14
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Smith RM, Kaushal SS, Beaulieu JJ, Pennino MJ, Welty C. Influence of infrastructure on water quality and greenhouse gas dynamics in urban streams. ACTA ACUST UNITED AC 2017; 14. [PMID: 32665782 DOI: 10.5194/bg-14-2831-2017] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Streams and rivers are significant sources of nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4) globally, and watershed management can alter greenhouse gas (GHG) emissions from streams. We hypothesized that urban infrastructure significantly alters downstream water quality and contributes to variability in GHG saturation and emissions. We measured gas saturation and estimated emission rates in headwaters of two urban stream networks (Red Run and Dead Run) of the Baltimore Ecosystem Study Long-Term Ecological Research project. We identified four combinations of stormwater and sanitary infrastructure present in these watersheds, including: (1) stream burial, (2) inline stormwater wetlands, (3) riparian/floodplain preservation, and (4) septic systems. We selected two first order catchments in each of these categories and measured GHG concentrations, emissions, and dissolved inorganic and organic carbon (DIC and DOC) and nutrient concentrations biweekly for 1 year. From a water quality perspective, the DOC : NO3 - ratio of streamwater was significantly different across infrastructure categories. Multiple linear regressions including DOC : NO3 - and other variables (dissolved oxygen, DO; total dissolved nitrogen, TDN; and temperature) explained much of the statistical variation in nitrous oxide (N2O, r2 = 0.78), carbon dioxide (CO2, r2 = 0.78) and methane (CH4, r 2 = 0.50) saturation in stream water. We measured N2O saturation ratios, which were among the highest reported in the literature for streams, ranging from 1.1 to 47 across all sites and dates. N2O saturation ratios were highest in streams draining watersheds with septic systems and strongly correlated with TDN. The CO2 saturation ratio was highly correlated with the N2O saturation ratio across all sites and dates, and the CO2 saturation ratio ranged from 1.1 to 73. CH4 was always supersaturated, with saturation ratios ranging from 3.0 to 2157. Longitudinal surveys extending form headwaters to third-order outlets of Red Run and Dead Run took place in spring and fall. Linear regressions of these data yielded significant negative relationships between each gas with increasing watershed size as well as consistent relationships between solutes (TDN or DOC, and DOC : TDN ratio) and gas saturation. Despite a decline in gas saturation between the headwaters and stream outlet, streams remained saturated with GHGs throughout the drainage network, suggesting that urban streams are continuous sources of CO2, CH4, and N2O. Our results suggest that infrastructure decisions can have significant effects on downstream water quality and greenhouse gases, and watershed management strategies may need to consider coupled impacts on urban water and air quality.
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Affiliation(s)
- Rose M Smith
- Department of Biology, University of Utah, Salt Lake City, UT 84112, USA.,Department of Geology, Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 20742, USA
| | - Sujay S Kaushal
- Department of Geology, Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 20742, USA
| | - Jake J Beaulieu
- US Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, Cincinnati, OH 45220, USA
| | - Michael J Pennino
- US Environmental Protection Agency National Health and Environmental Effects Research Lab, Corvallis, OR 97333, USA.,Department of Chemical, Biochemical, and Environmental Engineering, Center for Urban Environmental Research and Education, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Claire Welty
- Department of Chemical, Biochemical, and Environmental Engineering, Center for Urban Environmental Research and Education, University of Maryland Baltimore County, Baltimore, MD 21250, USA
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15
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Comparing the Life Cycle Energy Consumption, Global Warming and Eutrophication Potentials of Several Water and Waste Service Options. WATER 2016. [DOI: 10.3390/w8040154] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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16
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Xue X, Schoen ME, Ma XC, Hawkins TR, Ashbolt NJ, Cashdollar J, Garland J. Critical insights for a sustainability framework to address integrated community water services: Technical metrics and approaches. WATER RESEARCH 2015; 77:155-169. [PMID: 25864006 DOI: 10.1016/j.watres.2015.03.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2014] [Revised: 02/21/2015] [Accepted: 03/18/2015] [Indexed: 06/04/2023]
Abstract
Planning for sustainable community water systems requires a comprehensive understanding and assessment of the integrated source-drinking-wastewater systems over their life-cycles. Although traditional life cycle assessment and similar tools (e.g. footprints and emergy) have been applied to elements of these water services (i.e. water resources, drinking water, stormwater or wastewater treatment alone), we argue for the importance of developing and combining the system-based tools and metrics in order to holistically evaluate the complete water service system based on the concept of integrated resource management. We analyzed the strengths and weaknesses of key system-based tools and metrics, and discuss future directions to identify more sustainable municipal water services. Such efforts may include the need for novel metrics that address system adaptability to future changes and infrastructure robustness. Caution is also necessary when coupling fundamentally different tools so to avoid misunderstanding and consequently misleading decision-making.
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Affiliation(s)
- Xiaobo Xue
- Oak Ridge Institute for Science and Engineering (ORISE), National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268, USA.
| | - Mary E Schoen
- Soller Environmental, 312 NE 82nd St., Seattle, WA 98115, USA.
| | - Xin Cissy Ma
- National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268, USA.
| | - Troy R Hawkins
- National Risk Management Research Laboratory, U.S. Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268, USA.
| | - Nicholas J Ashbolt
- National Exposure Research Laboratory, U.S. Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268, USA.
| | - Jennifer Cashdollar
- National Exposure Research Laboratory, U.S. Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268, USA.
| | - Jay Garland
- National Exposure Research Laboratory, U.S. Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268, USA.
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17
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Wood A, Blackhurst M, Hawkins T, Xue X, Ashbolt N, Garland J. Cost-effectiveness of nitrogen mitigation by alternative household wastewater management technologies. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2015; 150:344-354. [PMID: 25575282 DOI: 10.1016/j.jenvman.2014.10.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 10/10/2014] [Indexed: 06/04/2023]
Abstract
Household wastewater, especially from conventional septic systems, is a major contributor to nitrogen pollution. Alternative household wastewater management technologies provide similar sewerage management services but their life cycle costs and nitrogen flow implications remain uncertain. This paper addresses two key questions: (1) what are the total costs, nitrogen mitigation potential, and cost-effectiveness of a range of conventional and alternative municipal wastewater treatment technologies, and (2) what uncertainties influence these outcomes and how can we improve our understanding of these technologies? We estimate a household nitrogen mass balance for various household wastewater treatment systems and combine this mass balance with life cycle cost assessment to calculate the cost-effectiveness of nitrogen mitigation, which we define as nitrogen removed from the local watershed. We apply our methods to Falmouth, MA, where failing septic systems have caused heightened eutrophication in local receiving water bodies. We find that flushing and dry (composting) urine-diversion toilets paired with conventional septic systems for greywater management demonstrate the lowest life cycle cost and highest cost-effectiveness (dollars per kilogram of nitrogen removed from the watershed). Composting toilets are also attractive options in some cases, particularly best-case nitrogen mitigation. Innovative/advanced septic systems designed for high-level nitrogen removal are cost-competitive options for newly constructed homes, except at their most expensive. A centralized wastewater treatment plant is the most expensive and least cost-effective option in all cases. Using a greywater recycling system with any treatment technology increases the cost without adding any nitrogen removal benefits. Sensitivity analysis shows that these results are robust considering a range of cases and uncertainties.
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Affiliation(s)
- Alison Wood
- The University of Texas at Austin, Dept. of Civil, Architectural, and Environmental Engineering, 301 E. Dean Keeton St. C8600, Austin, TX 78712-8600, United States.
| | - Michael Blackhurst
- The University of Texas at Austin, 301 E. Dean Keeton St. C2100, Austin, TX 78712-2100, United States
| | - Troy Hawkins
- U.S. Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, 26 W. Martin Luther King Drive, Cincinnati, OH, 45268, United States
| | - Xiaobo Xue
- ORISE Research Fellow, U.S. Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, 26 W. Martin Luther King Drive, Cincinnati, OH 45268, United States
| | - Nicholas Ashbolt
- U.S. Environmental Protection Agency, Office of Research and Development, National Exposure Research Laboratory, 26 W. Martin Luther King Drive, Cincinnati, OH, 45268, United States
| | - Jay Garland
- U.S. Environmental Protection Agency, Office of Research and Development, Microbiological and Chemical Exposure Assessment Research Division, 26 W. Martin Luther King Drive, Cincinnati, OH, 45268, United States
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18
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Baah K, Dubey B, Harvey R, McBean E. A risk-based approach to sanitary sewer pipe asset management. THE SCIENCE OF THE TOTAL ENVIRONMENT 2015; 505:1011-7. [PMID: 25461101 DOI: 10.1016/j.scitotenv.2014.10.040] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2014] [Revised: 10/01/2014] [Accepted: 10/12/2014] [Indexed: 05/20/2023]
Abstract
Wastewater collection systems are an important component of proper management of wastewater to prevent environmental and human health implications from mismanagement of anthropogenic waste. Due to aging and inadequate asset management practices, the wastewater collection assets of many cities around the globe are in a state of rapid decline and in need of urgent attention. Risk management is a tool which can help prioritize resources to better manage and rehabilitate wastewater collection systems. In this study, a risk matrix and a weighted sum multi-criteria decision-matrix are used to assess the consequence and risk of sewer pipe failure for a mid-sized city, using ArcGIS. The methodology shows that six percent of the uninspected sewer pipe assets of the case study have a high consequence of failure while four percent of the assets have a high risk of failure and hence provide priorities for inspection. A map incorporating risk of sewer pipe failure and consequence is developed to facilitate future planning, rehabilitation and maintenance programs. The consequence of failure assessment also includes a novel failure impact factor which captures the effect of structurally defective stormwater pipes on the failure assessment. The methodology recommended in this study can serve as a basis for future planning and decision making and has the potential to be universally applied by municipal sewer pipe asset managers globally to effectively manage the sanitary sewer pipe infrastructure within their jurisdiction.
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Affiliation(s)
- Kelly Baah
- School of Engineering, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2 W1, Canada
| | - Brajesh Dubey
- School of Engineering, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2 W1, Canada.
| | - Richard Harvey
- School of Engineering, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2 W1, Canada
| | - Edward McBean
- School of Engineering, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2 W1, Canada
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Loubet P, Roux P, Loiseau E, Bellon-Maurel V. Life cycle assessments of urban water systems: a comparative analysis of selected peer-reviewed literature. WATER RESEARCH 2014; 67:187-202. [PMID: 25282088 DOI: 10.1016/j.watres.2014.08.048] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 08/10/2014] [Accepted: 08/31/2014] [Indexed: 06/03/2023]
Abstract
Water is a growing concern in cities, and its sustainable management is very complex. Life cycle assessment (LCA) has been increasingly used to assess the environmental impacts of water technologies during the last 20 years. This review aims at compiling all LCA papers related to water technologies, out of which 18 LCA studies deals with whole urban water systems (UWS). A focus is carried out on these 18 case studies which are analyzed according to criteria derived from the four phases of LCA international standards. The results show that whereas the case studies share a common goal, i.e., providing quantitative information to policy makers on the environmental impacts of urban water systems and their forecasting scenarios, they are based on different scopes, resulting in the selection of different functional units and system boundaries. A quantitative comparison of life cycle inventory and life cycle impact assessment data is provided, and the results are discussed. It shows the superiority of information offered by multi-criteria approaches for decision making compared to that derived from mono-criterion. From this review, recommendations on the way to conduct the environmental assessment of urban water systems are given, e.g., the need to provide consistent mass balances in terms of emissions and water flows. Remaining challenges for urban water system LCAs are identified, such as a better consideration of water users and resources and the inclusion of recent LCA developments (territorial approaches and water-related impacts).
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Affiliation(s)
- Philippe Loubet
- Irstea, UMR ITAP, 361 rue Jean-François Breton, F-34196 Montpellier, France; Veolia Eau d'Île-de-France, 28 Boulevard du Pesaro, F-92739 Nanterre, France; ELSA, Research Group for Environmental Life Cycle Sustainability Assessment, 2 Place Pierre Viala, F-34060 Montpellier, France.
| | - Philippe Roux
- Irstea, UMR ITAP, 361 rue Jean-François Breton, F-34196 Montpellier, France; ELSA, Research Group for Environmental Life Cycle Sustainability Assessment, 2 Place Pierre Viala, F-34060 Montpellier, France
| | - Eleonore Loiseau
- Irstea, UMR ITAP, 361 rue Jean-François Breton, F-34196 Montpellier, France; ELSA, Research Group for Environmental Life Cycle Sustainability Assessment, 2 Place Pierre Viala, F-34060 Montpellier, France
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Ganigué R, Yuan Z. Impact of oxygen injection on CH4 and N2O emissions from rising main sewers. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2014; 144:279-285. [PMID: 24975803 DOI: 10.1016/j.jenvman.2014.04.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 04/22/2014] [Accepted: 04/22/2014] [Indexed: 06/03/2023]
Abstract
Oxygen injection is a commonly used mitigation strategy for sulfide control in sewers. Methane, a potent greenhouse gas, is also produced in sewers. Oxygen injection may reduce methane generation/emission, but could potentially lead to N2O production due to the development of a nitrifying microbial community. The impact of oxygen dosing for sulfide control in sewers on CH4 and N2O production was assessed in this study in laboratory sewer reactors. Results showed that oxygen injection is able to reduce CH4 formation in sewers, although full control of CH4 was not achieved, likely due to partial oxygen penetration into sewer biofilm. The experimental results also revealed a nitrogen loss of around 5 mN/L. However, no significant N2O accumulation was detected.
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Affiliation(s)
- Ramon Ganigué
- Advanced Water Management Centre, Building 60, Research Road, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia; LEQUIA, Institute of the Environment, University of Girona, Campus Montilivi, E-17071 Girona, Catalonia, Spain.
| | - Zhiguo Yuan
- Advanced Water Management Centre, Building 60, Research Road, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia.
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