WGK Engineers & Surveyors


Nutrient limits delayed for wastewater plants, implementation still unclear


The release of strict new water quality criteria for Mississippi may have been slightly delayed by federal budget cuts, but an unresolved process for implementing those criteria may already be pushing back the date when many of the state's wastewater operators will have to make changes to their treatment plants.

The Mississippi Department of Environmental Quality has delayed the original June 30 deadline for establishing water quality criteria - which will ultimately be used to develop nutrient limits for wastewater discharge permits - until later in 2013 after the federal government sequester affected the grant funding the research. The delay is expected to add two or three months of extra time to the process of developing draft numeric criteria, but it could be years before the new rules are implemented at the state's wastewater treatment plants, a process that will likely require the development of new methods and technology.

"Even when the new numeric criteria for nutrients are released, we don't know how long it will take for the numbers to show up in discharge permits," said Dr. Jon Huey, PE, BCEE, an environmental engineer with WGK, Inc.

Huey, who retired from environmental permitting at MDEQ, described a drawn-out scenario of procedures that would have to take place before any new water quality criteria are enforced on wastewater treatment plants.

Once the draft criteria are published, a 60- to 90-day public notice period will be held which will likely generate numerous comments from wastewater operators and other interested parties, all of which MDEQ will have to address. That done, an implementation process must be developed to incorporate the new criteria into discharge permit limits, and those limits still may not be applied until permits come up for renewal in the normal course of the 5-year renewal cycle. Legal challenges to any part of the process could also further delay implementation.

"There just aren't any answers yet," Huey said. "Coming up with the numbers, while challenging, is still the easy part. Figuring out how to apply them to every wastewater treatment plant in the state will be much more difficult."

Water quality criteria are required by the Clean Water Act of 1972. Numeric nutrient criteria are now being developed by states across the nation. The standards are meant to protect the water quality of the nation's rivers, lakes, wetlands and estuaries by limiting the discharge of nutrient pollutants, which can impair water quality by lowering oxygen levels and causing harmful algal blooms.

Several states in the Great Lakes and Chesapeake Bay areas and Florida have already begun implementing numeric limits on wastewater discharge, while other states have taken no action. In Mississippi, MDEQ has been gathering information and conducting analyses of water bodies for more than a decade, putting the state in a solid position to develop accurate and reasonable scientific criteria. The agency is conducting "stakeholder" meetings around the state to keep wastewater treatment owners and operators informed.

A growing number of the more than 4,000 wastewater treatment facilities in Mississippi are already required to meet nutrient loading limits, measured in pounds per day. Plants operating at less than full design flow have often been able to meet the loading limits with no - or only minor - modifications. However, the new criteria will have both loading limits and concentration limits (measured in milligrams per liter), and existing plants will probably have to undergo modifications.

While draft numeric nutrient criteria are still being developed, MDEQ has released some preliminary numbers that are likely to be very close to the draft values. The problem for wastewater treatment plant operators - especially the 387 publicly owned treatment works - is that the majority of plants may be unable to meet nutrient concentration limits without major upgrades.

"We know it is going to be a huge expenditure to get some of these plants up and running. There's just not enough money available to upgrade everyone at once.  This is where the implementation planning process comes in," said Kim Caviness, Chief of MDEQ's Water Quality Standards and Special Projects Branch.

Without processes to modify or components to upgrade, wastewater lagoons may find compliance with the new standards most difficult, Caviness pointed out. She said her agency may have to prioritize plants or allow longer compliance schedules.

"Some of our major plants have at least been monitoring for nutrients, but some of the smaller systems may have no data on what amount of nutrients they're discharging," she said.

Lagoon operators may be forced to choose between a small range of options, all of which have advantages and drawbacks: construct a sophisticated mechanical plant, relocate discharge points to streams with higher allowable nutrient concentration limits, convert to no-discharge land application systems or join regional wastewater groups and pump wastewater to a larger plant for treatment. MDEQ, through implementation planning, is committed to working with dischargers and consulting engineers to develop a “toolbox” of solutions so leaders can make informed decisions, Caviness said.

The forthcoming nutrient limits may cause competition for the allocation of limited waste loading capacity among treatment plants sharing a water body for discharging. The precedent of "first come, first served" will likely be abandoned, and permits may have to be adjusted among neighbors to maintain acceptable in-stream nutrient concentrations. Over-permitting - when treatment plants apply for permits with higher allowances than what is actually discharged to leave room for growth - will probably be disallowed. Municipalities or industries seeking to build new wastewater treatment plants would be wise to address nutrient removal in their designs.

As MDEQ and the participating regulatory bodies continue to calculate nutrient criteria and prepare for its implementation, WGK, Inc. is staying abreast of the developments, supplying new information to our clients and forecasting the impact, and addressing likelihoods in wastewater treatment designs. Waiting until the process is final and absolute may not save effort, but may instead eliminate options, said WGK Principal Greg Gearhart, PE, BCEE.

"Those of us who have been involved in the wastewater treatment industry since the 1980s have witnessed several cycles where permit requirements have become more and more restrictive, and the systems that have successfully met these restrictions are the ones that were proactive at the start," he said. "There are usually several good options that are available for achieving compliance with new limits, and thorough planning can identify those options while there is still time to prepare for them. Procrastination may leave you stuck with the option that is quickest - and most expensive."

Gearhart said WGK is working with its wastewater treatment clients to evaluate treatment options and technologies that are appropriate for each on a case-by-case basis and identifying funding strategies to minimize the eventual costs for their customers. Longer-term, phased improvement projects that utilize multiple funding sources are a great option for several types of systems and reduce the risk of last-minute upgrades, but preparations must begin immediately, he said.

"All of our clients have to be careful with their limited resources, and it is especially fulfilling to us when we're able to help them meet their responsibilities with creative, cost-effective solutions that protect them in the long run," Gearhart said.

If you are unsure of how your municipal or private wastewater treatment facility will be impacted by the changing regulations coming to Mississippi, contact WGK soon to schedule a site visit and consultation from our environmental engineers.