With rapid population growth worldwide, green building and development is becoming increasingly important. It is estimated that the world’s population is increasing at a rate of 80 million people per year, with the United States adding over 6,000 people per day from 2010 to 2016 (Suez Environmental, 2013; U.S. Census Bureau, 2017). In addition, the United States is currently experiencing human migration trends from the Northeast and Midwest regions to the South and West regions (U.S. Census Bureau, 2017).
The combination of population growth and relocation creates an increased demand for potable water, leading to amplified domestic wastewater production. The wastewater infrastructure supporting a population must change in response to population shifts on a local level. This frequently means the construction of new homes served by an onsite wastewater treatment system or expansion of the footprint and capacity of centralized wastewater treatment plants (WWTPs).
The economic and environmental benefits provided through the operation and maintenance (O&M) of centralized WWTPs and passive onsite wastewater treatment systems were quantitatively examined through an analysis of the unit cost, embodied carbon, and embodied energy of wastewater treatment. O&M data was collected from seventeen centralized WWTPs located in eight states. Average influent flows were broken down for this analysis into less than and greater than 7.5 million liters per day (2.0 million gallons per day).