Success Story

EPA MST Technologies

runoff from infrastructure

Water runoff from aging infrastructure. Photo by Eric Vance, U.S. EPA. (Photo credit: U.S. EPA)

According to the Environmental Protection Agency’s (EPA) National Water Quality Inventory Report to Congress, fecal bacteria are one of the leading causes of U.S. surface water impairment.

EPA scientists recently sought an innovative approach to monitor fecal pollution through the study of fecal bacterial communities at a molecular level. The result was the development of novel genetic-based technologies that can measure human and cattle fecal pollution levels in surface water samples. These patented microbial source tracking (MST) methods are technologies aimed at identifying and, in some instances, quantifying fecal animal sources of contamination in environmental waters.

Due to nationwide fecal pollution concerns there is a growing demand by academic, state, and municipal government laboratories to implement EPA MST technologies. To accommodate interest from nonprofit entities, the EPA developed non-commercial licenses for government agencies and universities. One government licensee of this technology is the Hampton Roads Sanitation District (HRSD), which protects water in 18 cities and counties in southeastern Virginia. In its first two years using EPA’s technology, HRSD has found great success applying the technology to monitor open water bodies and stormwater discharge.

HRSD has begun an effort to reduce bacteria contamination in local waterways by proactively identifying and repairing ailing and failing sewer infrastructure sources of human fecal contamination. The district has been using a variety of microbial source tracking tools to accomplish this mission, including utilization of EPA’s patented technology.

HRSD is focusing its efforts on identifying ailing and failing sewer infrastructure throughout its system. Their approach has been to target potential conduits of human fecal contamination using human-associated markers. Any stormwater outfalls that are found to be positive for a common human MST marker are investigated further by systematically sampling the upstream stormwater conveyance system at key access locations. Each time a branch point is encountered in the network, samples are collected upstream in each reach. In this way, the human-associated marker signal is traced through the stormwater infrastructure. When the extent of the signal has been demarcated in the stormwater conveyance system, adjacent sections of the sewer infrastructure are assessed for potential failure mechanisms. The initial effort uses one readily available human-associated marker (HF183); however, repairs to the sewer conveyance system are confirmed with the more specific markers developed by EPA.

One case study in HRSD’s jurisdiction involves Wayne Creek. HRSD personnel completed a downstream to upstream stormwater pipe network investigation, sampling every tributary stormwater outfall intersecting the stormwater network of interest. After delineating the problem area, the City of Norfolk identified a leaking sewer pipe in the Wayne Creek sub-watershed. Sampling conducted one month after the repair confirmed that there was no remaining human fecal contamination at the sampling sites.

Through its use of EPA’s licensed MST technology in concert with related MST technologies, HRSD is able to provide a healthier water system for its constituents.