Energy Profiles of Nine Water Treatment Plants in the Salt Lake City Area of Utah and Implications for Planning, Design, and Operation

Abstract

This study examined primary data on the energy use (electricity and natural gas) of nine surface water treatment plants in and around Salt Lake City, Utah, and how their energy use relates to their sizes, processes, and climates. The energy intensities per unit of treated water, averaged over a 3-year period, ranged from 0.059 to 0.565 kW·h/m3 [220–2,140 kW·h/million gal. (MG)] with a weighted average of 0.162 kW·h/m3 (610 kW·h/MG), concurring with the literature. The data confirmed economies of scale: larger plants and higher production had lower energy intensities. The analysis found energy differences for certain disinfection processes; ozone and ultraviolet disinfection required more energy than did chlorination. Significant energy baseloads (presumably for ventilation, lighting, and other building systems) were observed, even when little or no water was being treated. All sites had significant natural gas use, which was attributed mostly to space heating—33% to 67% of total energy—which should not be overlooked in energy management programs. Additional recommendations for sustainable planning, design, and operation of water treatment plants were discussed.