Sustainable life-cycle assessment of mixing approaches in water storage tanks

Abstract

Poor mixing in water storage tanks can cause stagnant zones that could pose negative public health effects. The present study uses Life Cycle Assessment to decide among the only three mixing options available, namely sprinkler, multiple inlets, and a mechanical mixer for the first time. These options were compared using different life-cycle assessment (LCA) tools using an 80-year lifetime as the functional unit while assuming that all three options result in acceptable water quality. Using SimaPro modeling software as well as the IPCC 2013 GWP 100a V1.0 and Cumulative Energy Demand methods, these three mixing approaches were compared with and without waste recycling. Results showed that application of a sprinkler is the least expensive option. Damage-cost analyses for categories of human health, ecosystem quality, and resources showed that a sprinkler caused the least damage and cost, while a mixer resulted in the most damage and cost. HIGHLIGHTS LCA proved effective in analyzing tank mixing technologies.; Sprinklers caused the least environmental damage and cost.; Mechanical mixers resulted in the most damage and cost.; Multiple inlet mixing had high damage but medium cost.;

Keywords

• cost evaluation
• life-cycle assessment
• mixing
• storage tanks