A comparative life cycle assessment of municipal wastewater treatment plants in Thailand under variable power schemes and effluent management programs

This life cycle assessment (LCA) study investigates the environmental impacts of seven wastewater treatment plants (WWTPs) in Thailand's capital Bangkok, using three power schemes and three effluent management programs (i.e. under nine scenarios). The three power schemes included the current electricity production, the next 5-year and 20-year electricity production plans. The power generation in the next 5 and 20 years would reduce the dependence on fossil fuels and increase the use of renewable energy. In addition, nuclear energy is included in the next 20-year power generation plan to further reduce the country's dependence on natural gas. Additionally, the objectives of this study also included the effluent management programs, which were the reuse for plant watering transported by truck and by pipeline. The study revealed that electricity use and thus the source of the electricity was the dominant contributor to almost all of the environmental impacts, except for the abiotic depletion and eutrophication. The results also showed that the effluent was largely responsible for the eutrophication impact. In addition, from these seven WWTPs, the Nongkaem plant had the lowest environmental impacts while the Sipraya plant had the highest. Furthermore, the 20-year power scheme exhibited the lowest global warming, the abiotic depletion (fossil fuels) and acidification impacts because of further reduction of fossil fuel (natural gas), whereas the current power scheme had the lowest photochemical oxidation and abiotic depletion impacts. Among the three effluent management programs, pipelining of effluent for plant watering exhibited the lowest environmental impacts.