GREENHOUSE GAS EMISSIONS FROM ALTERNATIVE WATER SUPPLY PROCESSES IN SOUTHERN CALIFORNIA, USA

Around the globe, burgeoning population centers and declining hydrological resources have encouraged the development of alternative water treatment systems, including desalination and wastewater recycling. These processes currently provide potable water for millions of people and assist in satisfying agricultural and landscaping irrigation demands. Although these alternative production methods help to reduce the burden placed on aquifers, they also emit significant amounts of greenhouse gases during their operation. The environmental advantages of these alternative water production methods need to be carefully weighed against their energy footprints and greenhouse gas emissions profiles.

Our study measured the greenhouse gas emissions of a wastewater treatment and recycling facility in Orange County, California in order to get a more complete picture of the carbon footprint of the plant. We measured atmospheric emissions of CO₂, CH₄, and N₂O throughout the water recycling process and at various times of the day and week. This allowed us to assemble a thorough, cross-sectional profile of greenhouse gas emissions from the facility. The known emissions due to chemical use and electrical production were added into our calculations, and the total carbon footprint was determined for the plant. We then compared the emissions of the wastewater recycling plant to the published emissions of desalination plants in order to assess the relative carbon footprints of the two water production methods. This research offers a valuable tool for sustainable urban and regional development by providing planners with a quantified comparison of the carbon footprints of these increasingly popular water production options.