Research Spotlight: AlexRenew and GMU Track Waterway Progress

It was an early August morning on the Potomac River. Leaving shore, the water was glassy still and blue, reflecting a clear sky. Above the water, osprey and egrets took flight as the boat approached, and below, small fish and shrimp darted into underwater grasses that swayed in the current. As we made our way around the river and Hunting Creek, the crew quickly set to work taking measurements and collecting samples.

Understanding Our Impact

In 2013, AlexRenew teamed up with George Mason University’s Potomac Environmental Research and Education Center (PEREC) to monitor the health of Hunting Creek.

“This study will help AlexRenew understand our long-term impact on the health of our watershed,” said Sean Stephan, Chief Enterprise Sustainability Officer. “Technology upgrades, process changes — all that we do here at AlexRenew affects the water leaving our facility.”

By sampling regularly throughout the year, PEREC is “keeping a finger on the pulse of water quality,” said Dr. Christian Jones, Director of PEREC. “This monitoring study paints an ongoing picture of water quality in Hunting Creek.” 

Knowing the ongoing condition of Hunting Creek enables the team to gauge whether water quality is improving over time, and if so, what that means for life in the river. 

Looking for Life

PEREC is monitoring the water environment by looking at plankton, fish communities, and benthos — the creatures found in the sediment on the bottom of the river.

PEREC’s most “eye-catching” discovery is that fish, including shad and alewife, are spawning in urban streams like Cameron Run, which flows into Hunting Creek and on into the Potomac River.

“This means we need to be careful of how we are impacting urban and suburban streams,” said Jones. “They do harbor life.”

According to Jones, changes in the way wastewater utilities disinfect their water has helped fish. Chlorine — used in swimming pools to keep germs from spreading — is also commonly used to disinfect wastewater. This helps protect public health, but when active chlorine is released into the environment, it can negatively impact life in the stream. In 2002, AlexRenew installed one of the first large-scale UV disinfection systems, a chemical-free way to destroy disease-causing bacteria. This is just one example of how advances in wastewater technology can improve the water environment.

Jones and his team have sampled streams in the area since 1984, and they have also seen a resurgence in underwater grasses. These grasses are important because they provide food, shelter, and protection for aquatic animals, among other benefits. The rising number of underwater grasses is a positive trend seen in the Chesapeake Bay too, with grasses increasing 21 percent between 2014 and 2015. 

Upgrading Water Quality

As PEREC conducts its surveys, AlexRenew’s lab team analyzes the water samples for pollutants like nutrients and E. coli,  an indicator of fecal contamination from humans and other animals. In excess, nutrients (especially nitrogen and phosphorus) can cause algal blooms, which diminish water quality and harm wildlife.

AlexRenew completed major construction of our State-of-the Art Nitrogen Upgrade Program (SANUP) in 2016. This infrastructure upgrade will reduce the total nitrogen we discharge to the Potomac River and Chesapeake Bay by an additional 20% annually.

As PEREC monitors the health of Hunting Creek long-term, we expect that upgrades like SANUP will produce measurable improvements in water quality.  


As part of SANUP, AlexRenew is introducing Anammox bacteria, also called red bugs, into the water cleaning process. These special bacteria need fewer resources — air and food — to remove nitrogen, helping AlexRenew reduce the amount of energy and chemicals we use. AlexRenew will be among the first to implement a full-scale mainstream Anammox facility. 

Kristen Reck, a graduate student with George Mason University, is working part-time with AlexRenew expert and Process Manager Hong Yin to study how the red bugs perform in AlexRenew’s mainstream facility. Reck is also looking at whether the red bugs affect communities of bacteria living in Hunting Creek. Red bugs exist in the natural environment and are safe to use in the wastewater treatment process, but these bacteria are typically rare.

“Working both inside and outside the AlexRenew facility provides a unique perspective,” Reck said. “AlexRenew is not operating in a vacuum. The work they do has real world effects, and it is interesting to study those effects on waterways so close to home.”

Monitoring Emerging Threats

The team is also looking at micropollutants, contaminants found in medications and personal care products. The wastewater treatment process is not designed to remove these pollutants, and their impact on waterways is of growing concern.

Common examples include ingredients used in pain killers and antibiotics, calling attention to the fact that unused medications should never be flushed down the drain. Some other common micropollutants like triclosan — an antibacterial agent found in soap — and microbeads — typically used in facewash and body scrubs — have both been banned nationally.

Bans and behavior changes can stop pollution at the source, which is often more effective and less costly for ratepayers than installing new technologies at wastewater treatment plants. Yet these solutions also underscore the growing need for wastewater utilities to form strong community partnerships to help spread the message of water stewardship.


AlexRenew began operating in 1956, and has changed dramatically over the last 60 years as infrastructure ages, technology changes, and regulations require stronger protections for local waterways. Through our partnership with PEREC, we look forward to learning more about how the environment responds to current and future improvements made at AlexRenew and in our community.