It’s well known among the country’s wastewater treatment professionals that nutrient pollution has become one of the most challenging water quality problems. High levels of nitrogen and phosphorus, combined with rising temperatures, have made toxic algal bloom a seasonal rite of passage that poses serious health risks.
According to National Aquatic Resource Surveys from the U.S. EPA, almost 20 percent of the nation’s lakes had high levels of nitrogen and phosphorus pollution in 2010, 30 percent of streams across the country had high levels in 2006, and states identified about 15,000 water bodies as having one or more nutrient-related impairments, all figures that have surely risen since they were collected. Reported drinking water violations for nitrates have doubled in the last eight years, per the agency.
In acknowledgement of the problem, the EPA has launched a “National Study of Nutrient Removal and Secondary Technologies” that will focus on municipal wastewater treatment plants (or publicly owned treatment works (POTWs) as they are known around EPA offices). As a first step, the agency has initiated an information collection request for all wastewater plants in the country through mid-November.
“More and more states are adopting nutrient frameworks and strategies, making it increasingly necessary for wastewater treatment facilities, both major and minor, to address nutrient issues,” said an EPA spokesperson. “Large information gaps exist nationally for nutrient contributions from wastewater treatment plants. EPA and its partners recognize that case studies and anecdotes cannot extrapolate the variety of POTWs nationwide to address nutrient issues.”
Even though 34 percent of major dischargers have permit limits for nutrients and 63 percent have monitoring requirements for nutrients in their effluent, not enough is known about the overall nutrient removal picture to provide effective advice to the rest of the country. The EPA launched the study to establish a baseline of nutrient removal and to identify the practices that can improve nutrient removal at different types of plants.
“The information generated by the study is critical for POTWs, states, tribes, and EPA to work together to determine realistic, achievable waste load allocations and nutrient reduction strategies,” said the spokesperson.
The EPA expects to send survey questions to about 18,000 treatment plants (at an estimated cost of $65 to $147 per respondent) and has kept questions simple to encourage a high response rate. Once it gets a handle on the complete population of the country’s municipal wastewater operations, it will single out a statistically representative sample for further study. Then, the EPA will collect sampling data from influent, effluent, and in-plant processes and use it to determine the nutrient removal efficiency of the country’s wastewater treatment plants. From there, it can validate the best practices and share them nationwide. It expects the full study to be conducted over four to five years.
“This study will provide the tools needed by POTWs to identify and implement low-cost practices that may be available to secondary treatment facilities based on their similarities to facilities achieving nutrient removal improvements,” the spokesperson said. “The study will also provide the information necessary for states to make realistic and achievable nutrient strategies and waste load allocations for POTWs.”
Once the information is collected and processed, the EPA knows it will have to present it in a way that’s easily applied by those plants suffering most from nutrient pollution.
“EPA has already initiated a collaborative effort with trade associations, POTWs, and field experts to make sure the information is understandable and useable by stakeholders,” said the spokesperson. “EPA has not yet identified the final form the information will take, however the information will be made publicly available and in a form that is useable by POTWs, states, and other interested stakeholders.”
Unfortunately, the nutrient pollution problem will likely be even worse by the time information from the study becomes publicly available. In the meantime, wastewater treatment plants will have to do their best to hold the fort.
Image credit: ""Green Stuff" ---- Wakodahatchee," Jan © 2007, used under an Attribution 2.0 Generic license: https://creativecommons.org/licenses/by/2.0/