Life Cycle Environmental Impact Assessment of Steel and Plastic Tanks in Water Treatment Facilities

Abstract

This study evaluated the life cycle environmental impacts of steel and plastic tanks used in water treatment facilities and examined the influence of material selection. The system boundary included manufacturing, transportation, and disposal. Greenhouse gas (GHG) emissions were quantified using primary data obtained through interviews with multiple manufacturers, and environmental impacts were evaluated using LIME2. GHG emissions of a plastic tank (20m3) were 42-68% lower than those of steel tanks, indicating that appropriate material selection can reduce GHG emissions. For sensitivity analysis, plastic tank disposal was changed from industrial waste treatment involving partial recycling to complete incineration. GHG emissions remained 22–57% lower than those of steel tanks. Plastic tanks can maintain lower life cycle GHG emissions than steel tanks even under complete incineration. The integrated assessment indicated that the environmental impact of steel tanks was approximately nine times than that of plastic tanks. Biodiversity and primary production accounted for approximately 80% of the integrated impact. Contribution analysis revealed that natural rubber used in the rubber lining was a major contributing factor. These results suggest that the selection of lining materials and optimization of their usage could be important for reducing environmental impacts.