Since the Sustainable Development Goals (SDGs) were set up in 2015, private companies have been accelerating their efforts on SDGs. Also, as more investors make their decision based on Environmental, Social, and Governance (ESG) criteria to evaluate companies, private companies are required to show their efforts on ESG quantitatively. To achieve SDGs Goal 6 “Ensure availability and sustainable management of water and sanitation for all,” private companies, especially based in developing countries, are required to appropriately treat domestic wastewater. However, it is indicated that conventional septic tanks emit a large amount of greenhouse gas (GHG) as well as discharge effluent containing high BOD directly into the environment. To improve the wastewater treatment system, Japanese Johkasou systhem is expected to be installed instead of conventional septic tanks. A previous research1) shows that GHG emission from septic tank is 1.8 times higher than Johkasou. However, other than GHG, other environmental impact also need to be considered to respond to SDGs and ESG. This study conducted to investigate and compare the environmental impact of two types of on-site domestic wastewater treatment systems installed in factories in Indonesia, a conventional septic tank and a Johkasou. The methodology used for the impact assessment was LIME3. As a result, the environmental impact of the entire life cycle of the septic tank was 1.04 USD per person per year and 0.47USD for Johkasou. Both have the largest environmental impact at the stage of operation, but the main factors were different. As for septic tank, CH4 emission from the wastewater treatment accounts for about 71% of the total emission, on the other hand, Johkasou emits about 55% of CO2 from power consumption used for a blower. The result shows there are possibility to reduce 55% of the environmental impact if Johkasou is installed instead of conventional septic tank.
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