Environmental life cycle assessment of different domestic wastewater streams : policy effectiveness in a tropical urban environment
To enhance local water security, the Singapore government promotes two water conservation policies: the use of eco-friendly toilets to reduce yellow water (YW) disposal and the installation of water efficient devices to minimize gray water (GW) discharge. The proposed water conservation policies hav...
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sg-ntu-dr.10356-1035852020-03-07T11:45:55Z Environmental life cycle assessment of different domestic wastewater streams : policy effectiveness in a tropical urban environment Ng, Bernard J.H. Zhou, Jin Giannis, Apostolos Wang, Jing-Yuan Chang, Victor Wei-Chung School of Civil and Environmental Engineering Nanyang Environment and Water Research Institute DRNTU::Engineering::Civil engineering::Water resources To enhance local water security, the Singapore government promotes two water conservation policies: the use of eco-friendly toilets to reduce yellow water (YW) disposal and the installation of water efficient devices to minimize gray water (GW) discharge. The proposed water conservation policies have different impacts on the environmental performance of local wastewater management. The main purpose of this study is to examine and compare the impacts of different domestic wastewater streams and the effectiveness of two water conservation policies by means of life cycle assessment (LCA). LCA is used to compare three scenarios, including a baseline scenario (BL), YW-reduced scenario (YWR) and GW-reduced scenario (GWR). The BL is designed based on the current wastewater management system, whereas the latter two scenarios are constructed according to the two water conservation policies that are proposed by the Singapore government. The software SIMPARO 7.3 with local data and an eco-invent database is used to build up the model, and the functional unit is defined as the daily wastewater disposal of a Singapore resident. Due to local water supply characteristics, the system boundary is extended to include the sewage sludge management and tap water production processes. The characterization results indicate that the GWR has a significant impact reduction (22–25%) while the YWR has only a 2–4% impact reduction compared with the BL. The contribution analysis reveals that the GW dominates many impact categories except eutrophication potential. The tap water production is identified as the most influential process due to its high embodied energy demand in a local context. Life cycle costing analysis shows that both YWR and GWR are financially favorable. It is also revealed that the current water conservation policies could only achieve Singapore's short-term targets. Therefore, two additional strategies are recommended for achieving long-term goals. This study provides a comprehensive and reliable environmental profile of Singapore's wastewater management with the help of extended system boundary and local data. This work also fills the research gap of previous studies by identifying the contribution of different wastewater streams, which would serve as a good reference for source-separating sanitation system design. Accepted version 2014-04-29T08:57:32Z 2019-12-06T21:15:59Z 2014-04-29T08:57:32Z 2019-12-06T21:15:59Z 2014 2014 Journal Article Ng, B. J., Zhou, J., Giannis, A., Chang, V. W. C., & Wang, J. Y. (2014). Environmental life cycle assessment of different domestic wastewater streams: Policy effectiveness in a tropical urban environment. Journal of Environmental Management, 140, 60-68. 0301-4797 https://hdl.handle.net/10356/103585 http://hdl.handle.net/10220/19274 10.1016/j.jenvman.2014.01.052 179247 en Journal of environmental management © 2014 Elsevier Ltd. This is the author created version of a work that has been peer reviewed and accepted for publication by Journal of Environmental Management, Elsevier. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [http://dx.doi.org/10.1016/j.jenvman.2014.01.052]. application/pdf |
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DRNTU::Engineering::Civil engineering::Water resources Ng, Bernard J.H. Zhou, Jin Giannis, Apostolos Wang, Jing-Yuan Chang, Victor Wei-Chung Environmental life cycle assessment of different domestic wastewater streams : policy effectiveness in a tropical urban environment |
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To enhance local water security, the Singapore government promotes two water conservation policies: the use of eco-friendly toilets to reduce yellow water (YW) disposal and the installation of water efficient devices to minimize gray water (GW) discharge. The proposed water conservation policies have different impacts on the environmental performance of local wastewater management. The main purpose of this study is to examine and compare the impacts of different domestic wastewater streams and the effectiveness of two water conservation policies by means of life cycle assessment (LCA). LCA is used to compare three scenarios, including a baseline scenario (BL), YW-reduced scenario (YWR) and GW-reduced scenario (GWR). The BL is designed based on the current wastewater management system, whereas the latter two scenarios are constructed according to the two water conservation policies that are proposed by the Singapore government. The software SIMPARO 7.3 with local data and an eco-invent database is used to build up the model, and the functional unit is defined as the daily wastewater disposal of a Singapore resident. Due to local water supply characteristics, the system boundary is extended to include the sewage sludge management and tap water production processes. The characterization results indicate that the GWR has a significant impact reduction (22–25%) while the YWR has only a 2–4% impact reduction compared with the BL. The contribution analysis reveals that the GW dominates many impact categories except eutrophication potential. The tap water production is identified as the most influential process due to its high embodied energy demand in a local context. Life cycle costing analysis shows that both YWR and GWR are financially favorable. It is also revealed that the current water conservation policies could only achieve Singapore's short-term targets. Therefore, two additional strategies are recommended for achieving long-term goals. This study provides a comprehensive and reliable environmental profile of Singapore's wastewater management with the help of extended system boundary and local data. This work also fills the research gap of previous studies by identifying the contribution of different wastewater streams, which would serve as a good reference for source-separating sanitation system design. |
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School of Civil and Environmental Engineering |
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School of Civil and Environmental Engineering Ng, Bernard J.H. Zhou, Jin Giannis, Apostolos Wang, Jing-Yuan Chang, Victor Wei-Chung |
format |
Article |
author |
Ng, Bernard J.H. Zhou, Jin Giannis, Apostolos Wang, Jing-Yuan Chang, Victor Wei-Chung |
author_sort |
Ng, Bernard J.H. |
title |
Environmental life cycle assessment of different domestic wastewater streams : policy effectiveness in a tropical urban environment |
title_short |
Environmental life cycle assessment of different domestic wastewater streams : policy effectiveness in a tropical urban environment |
title_full |
Environmental life cycle assessment of different domestic wastewater streams : policy effectiveness in a tropical urban environment |
title_fullStr |
Environmental life cycle assessment of different domestic wastewater streams : policy effectiveness in a tropical urban environment |
title_full_unstemmed |
Environmental life cycle assessment of different domestic wastewater streams : policy effectiveness in a tropical urban environment |
title_sort |
environmental life cycle assessment of different domestic wastewater streams : policy effectiveness in a tropical urban environment |
publishDate |
2014 |
url |
https://hdl.handle.net/10356/103585 http://hdl.handle.net/10220/19274 |
_version_ |
1681045362254544896 |