Life cycle assessment of greenhouse gas emissions from an urban water system : a case study of Phnom Penh city, Cambodia | |
| Author | Seangly, Pao |
| Call Number | AIT Thesis no.EV-25-11 |
| Subject(s) | Greenhouse gases--Cambodia--Phnom Penh Water-supply--Environmental aspects--Cambodia--Phnom Penh |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Environmental Engineering and Management |
| Publisher | Asian Institute of Technology |
| Abstract | Urban water systems (UWSs) are essential for sustainable development but are major contributors to greenhouse gas (GHG) emissions through both direct and indirect emissions related to energy and water use. Tackling this issue is vital for cities to meet climate commitments while providing efficient water and sanitation services. Therefore, this study aims to conduct a whole-system analysis of GHG emissions associated with UWSs, including water abstraction, treatment, distribution, wastewater collection which includes containments (septic tank and cesspit) for onsite sanitation systems and conveyance (sewer network and pumping stations) for sewered sanitation systems, wastewater treatment, and final discharge into water bodies, taking Phnom Penh City as a case study. The quantification of GHG emissions was done using a Life Cycle Assessment (LCA) approach, accounting for both construction stage considering materials used and operational stage considering various activities of energy usage and biological activity leading to GHG emissions. Direct GHG emissions from wastewater processes were calculated based on IPCC guidelines, while indirect emissions were assessed using methodologies adopted from Singh and Kansal (2018); Jonhson et al. (2022) and GHG protocol guideline. Scenario analysis was performed to evaluate the potential impacts of different assumptions and future conditions in 2030, while sensitivity analysis was done to account for potential variability in the results.The results showed that onsite fecal sludge containment systems contribute the highest GHG emissions for both construction and operation phases, accounting for 325,847 t CO2-eq (65%). Other major contributors include the discharge system at 111,171 t CO2-eq (22%), pumping stations at 42,976 t CO2-eq (8.70%), DWTPs at 8,076 t CO2-eq (1.63%), the sewer network at 3,466 t CO2-eq (0.70%), FSTP at 1,309 t CO2-eq (0.27%), and WWTPs at 1,254 t CO2-eq (0.25%). In terms of emissions per capita per year (2024), water systems have a lower contribution compared to wastewater systems. Specifically, water systems account for 24.98 kg CO₂-eq/cap/year, while wastewater systems contribute significantly more, at 228 kg CO₂-eq/cap/year. The highest energy consumption within the wastewater sector is attributed to pumping stations, which require 0.19 kWh/m3. These findings highlight the substantial role of UWS in overall GHG emissions, emphasizing their importance in sustainable urban development planning and climate mitigation strategies. |
| Year | 2025 |
| Type | Thesis |
| School | School of Engineering and Technology |
| Department | Department of Water Resources and Environmental Engineering (DWREE) |
| Academic Program/FoS | Environmental Engineering and Management (EV) |
| Chairperson(s) | Ghimire, Anish |
| Examination Committee(s) | Thammarat Koottatep;Shanmugam, Mohana Sundaram |
| Scholarship Donor(s) | Loom Nam Khong Pijai (Greater Mekong Subregion) Scholarships; |
| Degree | Thesis (M. Sc.) - Asian Institute of Technology, 2025 |