ADVANCEMENT OF THE PRACTICE
Open Access
DIRECT FROM U.S. EPA OFFICE OF RESEARCH AND DEVELOPMENT
Toward Better Decentralized Wastewater Treatment
Laura E. Erban, PhD
Timothy R. Gleason, PhD
ing bacteria, viruses, nutrients, pharmaceuti- cals, and per- and polyfluoroalkyl substances (PFAS), among other regulated and emerging contaminants, contributes to a wide range of potential hazards for people and ecosystems. In coastal counties, where approximately 40% of the U.S. population live (National Oceanic and Atmospheric Administration, 2013), onsite wastewater treatment systems (OWTS) are found at high densities, largely in the form of conventional septic systems. Pollutants in e uent are only partly treated by underlying soils, sediments, and associ- ated microbial communities. Groundwater is often the sole source of drinking water, and it transports nutrients and co-pollutants in wastewater to aquatic ecosystems. Along with rising temperatures, excess nutrients increase the likelihood of nuisance and harmful algal blooms (HABs). Blooms can deter tourism, produce toxins harmful to humans and ani- mals, cause fish kills, and destroy habitats over time. In the Northeast, e uent from dense unsewered housing has overloaded estuaries, which have lost seagrass, fish, and shellfish, undermining blue economies and ways of life that depend on coastal waters. Solutions-Driven Research The Oce of Research and Development (ORD) within the U.S. Environmental Pro- tection Agency (U.S. EPA) works closely with local, regional, and federal partners to advance remedies for excess nutrients and co-pol- lutants across the country. In Cape Cod, the southeast arm of Massachusetts, estuaries are impaired by excess nitrogen that is predomi- nantly sourced by OWTS. Estuarine total max- imum daily loads (TMDLs) call for significant reductions in wastewater nitrogen to restore
Editor’s Note: The National Environmental Health Association strives to provide up-to-date and relevant information on environmental health and to build partnerships in the profession. In pursuit of these goals, we have partnered with the Oce of Research and Development (ORD) within the U.S. Environmental Protection Agency (U.S. EPA) to publish two columns a year in the Journal . ORD is the scientific research arm of U.S. EPA. ORD conducts the research for U.S. EPA that provides the foundation for credible decision-making to safeguard human health and ecosystems from environmental pollutants. In these columns, authors from ORD will share insights and information about the research being conducted on pressing environmental health issues. The views and conclusions in these columns are those of the author(s) and do not necessarily represent the views or policies of U.S. EPA. Any mention of trade names, manufacturers, or products does not imply an endorsement by the U.S. government or U.S. EPA. U.S. EPA and its employees do not endorse any commercial products, services, or enterprises. Dr. Laura Erban is a groundwater hydrologist for ORD. Her research focuses on the safe and sustainable use of water resources and hazard mitigation. Dr. Timothy Gleason is the director for the Atlantic Coastal Environmental Sciences Division within ORD and the Center for Environmental Measurement and Modeling. He has a broad range of experience in marine and coastal environmental research.
Introduction Clean water is essential to human and eco- logical health and robust economies. Many pollutants can impair water quality, and domestic wastewater is an important source of pollutants. An estimated 32 million hous- ing units in the U.S., more than 25%, are not connected to sewers and centralized waste- water treatment plants but instead use decen-
tralized or onsite wastewater disposal systems that vary in form and function (Maxcy-Brown et al., 2023). In at least 15 states, households have straight pipes that discharge raw sewage to open pits or streams. Cesspools and septic systems that discharge e uent below ground can contaminate drinking water wells and groundwater-receiving surface waters. Direct and indirect exposure to wastewater contain-
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