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Park Receives NSF Grant to Study How Upgrading Wastewater Treatment Plants to Decrease Nitrogen Discharge Can Trigger Algal Blooms in Coastal Water

Chul Park (r) and Hans Paerl (l) at Neuse River Estuary

Dr. Chul Park, an associate professor in the Civil and Environmental Engineering Department, and his collaborator, Dr. Hans Paerl, a professor in the Institute of Marine Sciences at the University of North Carolina Chapel Hill, recently received a three-year, collaborative grant of $330,000 from the National Science Foundation (NSF). The NSF grant will support the joint research team’s investigation into the potentially unforeseen and unintended impact of upgrading wastewater treatment systems to decrease nitrogen on algal blooms in coastal water systems.

The UMass team, led by Park, is the lead of this new inter-institutional collaborative research project. The NSF grant was issued by its Division of Chemical, Bioengineering, Environmental, and Transportation Systems.

As Park explains “Coastal waters throughout the developed world suffer from eutrophication mediated by excessive nitrogen loads. Algal blooms, causing oxygen depletion (hypoxia) and food web changes, are among the most troublesome symptoms of eutrophication, threatening sustainability of these waters.”

Park goes on to say that “Significant decreases in the nitrogen-rich runoff from urban areas have been achieved by advanced or upgraded wastewater treatment plants that can effectively remove nitrogen. However, despite past successes, many coastal systems still experience excessive algal blooms.”

Park and Paerl hypothesize that the cause of continued growth of algal blooms is related to the engineering of nutrient treatment processes.

Park says that “We found that pre-denitrification biological nutrient removal processes, the most common way to decrease inorganic nitrogen discharge from wastewater treatment plants, have a high tendency to produce small yet significant amounts of organic nitrogen, which is not the case for the conventional treatment systems.

Park adds that this nitrogen-containing organic matter is extremely small in size, and it appears to greatly stimulate algal growth in offshore waters. Based on Park and Paerl’s preliminary studies, algae growth with this small-sized organic nitrogen is substantially greater than the growth typically observed with inorganic nitrogen, such as ammonia and nitrate.

“To examine this hypothesis,” says Park, “this research will investigate the potential linkage of advanced wastewater treatment plant discharge and algal-bloom formation in coastal waters, with the goal of developing new and more effective nutrient-reduction strategies.”

This interdisciplinary research combines expertise in environmental engineering with environmental biology and ecology. Park’s team will employ both lab and field investigations on the production of small-sized organic nitrogen from biological nutrient removal systems. Paerl’s team will focus on in situ bioassays on water from the Neuse River Estuary in North Carolina to investigate the qualitative and quantitative effects of nitrogen in effluents on phytoplankton production and community structure. 

The research is aimed at having far-reaching impacts for the understanding of the role of wastewater treatment in both eutrophication and structuring of phytoplankton communities in coastal waters. Furthermore, the project will shed light on mechanisms coupling specific nitrogen inputs to coastal eutrophication and harmful bloom dynamics.

The results of this research could transform how nitrogen is managed to mitigate eutrophication in coastal waters.

Park concludes that “I am so excited and honored to work with Dr. Paerl, the world’s renowned researcher on cyanobacterial and algal biology, especially for our natural environment which has direct interaction with our built environmental systems, including wastewater treatment plants. I hope we will learn many new things through this collaborative project.” (July 2019)