EPA assessing wastewater nutrient pollution

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Courtesy of Fluence Corporation

Nutrient pollution of waterways is the “single greatest challenge to our nation’s water quality,” according to the United States Environmental Protection Agency. Across the U.S., excess nitrogen and phosphorus are entering waterways, presenting seemingly constant challenges. To address these challenges, the EPA is surveying the nation’s publicly owned wastewater treatment facilities.

The multiphase, multiyear study will identify and map all municipal wastewater treatment facilities in the U.S., according to the EPA. Information will be collected about the treatment technology each uses and how effectively the facility removes nutrients. One goal is to create a national baseline for both nutrient removal and discharges.

In announcing the study, the agency said:

Nutrient pollution is one of America’s most widespread, costly and challenging environmental problems impacting water quality. Excessive nitrogen and phosphorus in our waters can lead to a variety of problems including eutrophication and harmful algal blooms, with impacts on drinking water, recreation and aquatic life. A wide range of human activities can contribute to nutrient pollution including stormwater runoff, agriculture, and wastewater discharges.

Nitrogen and Phosphorus Pollution

When fresh water is too rich with nutrients — called eutrophication — it becomes a breeding ground for algae. The nutrients include naturally occurring nitrates and phosphates, or those introduced by fertilizer and other agricultural runoff, or sewage discharge. This can be resolved through stringent pollution controls as well as better wastewater treatment, which lowers the amount of nutrients entering waterways.

The ongoing problems posed by nutrient pollution have grown increasingly evident in the last several years through incidents such as the toxic algal blooms in Lake Erie in 2014 and the state of emergency created in Florida from a combination of nutrient-rich drainage from Lake Okeechobee and stormwater runoff. The guacamole-thick matted algae bloom was 33 miles wide and could be seen from space, according to NASA.

In 2016, through mid-August, more than 250 health advisories were issued for toxic algae conditions in the U.S., according to Circle of Blue.

Reducing Nutrients Released Into Waterways

Joel Beauvais, head of the EPA water office, wrote in a letter sent to state officials in September:

While many entities have taken meaningful actions to reduce nutrient pollution, there continues to be a pressing need for concerted action to reduce nutrient pollution nationwide

However, the agency is challenged by a lack of information needed to better understand the problem and devise solutions. The nation’s 16,000 public wastewater treatment facilities are the largest source of nutrient pollution for some watersheds, but the EPA doesn’t have a comprehensive database of related information. Circle of Blue notes:

Only one-third of the largest facilities have enforceable limits on nitrogen and phosphorus discharges, and less than two-thirds are required to monitor the two pollutants.

Developing Best Practices

The agency also wants to develop best practices for both management and operations. Proven low-cost strategies for effective nutrient removal should help facilities decrease operational energy demands without large capital investment.

Operational changes cited by the EPA in an August 2015 report included reducing excess oxygen added via aeration, and creating wetlands and swales for to filter effluent naturally before it enters waterways.

The Victor Valley Wastewater Reclamation Authority in California reduced its total nitrogen discharge by more than 25 percent solely by changing its aeration process and implementing variable speed controls. The EPA compared this project’s cost — $1.1 million — to an investment of $80 million for a nitrogen-removal unit.

According to the White House, as an added benefit, the operation trimmed energy use by 27 percent and operating costs by 10 percent. The plant produces biogas for cogeneration and also participates in the water-wastewater treatment pilot for the U.S. Department of Energy’s Superior Energy Performance program.

The EPA plans to hold webinars in 2017 before the final version of the questionnaire is sent to wastewater treatment facilities in mid-2017. The EPA adds that the responses, to be collected under the powers given the agency via the Clean Water Act, will gather information for research purposes, not to check on facilities’ compliance.

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