Learning From Chesapeake Bay Study

An onsite wastewater panel recommends all states in the sensitive watershed area agree on best management practices protocol for reducing nitrogen load.

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In January 2012, I was asked to serve on an expert panel to review available science on the pollutant removal performance of treatment practices to derive nutrient removal rates for individual onsite wastewater practices. This ended up being a nearly two-year process culminating in a December 2013 workshop held in Washington, D.C.

The practices in question were those currently in use or with the potential for use in the Chesapeake Bay watershed bordering Maryland and several other eastern states. The primary objective was to review documentation, and provide concise system definitions and percent reductions for nitrogen load reduction practices that could then be used in a model to evaluate how changes in practices will impact nitrogen loadings to Chesapeake Bay.

So if you’re a pumper in Texas or Minnesota or Florida, why should this study interest you? Because the microscope now focused on the Eastern Seaboard will eventually turn elsewhere. What happens in the Chesapeake Bay watershed has the potential to impact how you will do business in the future by determining what kinds of systems will be installed in those areas.

THE TASK AT HAND

The Chesapeake Bay panel, in addition to the primary objective, was to:

  • Recommend whether to establish interim removal treatment rates prior to the conclusion of the panel to assist with the watershed implementation  plan;
  • Recommend procedures for reporting, tracking and verifying the recommended retrofit credits; and
  • Critically analyze any unintended consequences associated with the credits and any potential for double- or over-counting the credits.

The panel divided appropriate best management practices (BMP) into two main categories: BMPs that occur prior to the drainfield and BMPs that are implemented as enhancements to the soil treatment unit, including the drainfield. Reduction credits for BMPs prior to the drainfield were compared to the baseline of 5 kg TN per person per year associated with septic tank effluent. Reduction credits for enhancements and combined BMPs were compared with the baseline edge-of-drainfield performance of 4 kg TN per person per year that was used to model the performance of a conventional septic tank coupled with a gravity-flow drainfield.

The technologies evaluated prior to the drainfield included ATUs, media filters, recirculating media filters, constructed wetlands and several state-specific proprietary products. In terms of the enhancements, they included shallow pressure-dosed systems, including both low-pressure pipe systems and drip irrigation systems, elevated sand mounds and at-grade systems, and reactive permeable barrier systems. In addition, the panel recommended a two-tiered approval protocol to be followed for proprietary systems that make claims of nitrogen reduction.

MANAGEMENT MODEL

The proprietary BMP protocol consists of an initial provisional approval on the basis of a recognized third-party testing protocol. A final approval, based on the results of the field testing, is also recommended. Nonproprietary BMPs, however, need to be evaluated on an individual basis unless the state or local government validates the performance of nonproprietary systems that are constructed with standardized system designs and materials and operated under recognized and specified O&M protocols.

The panel recommended that, at a minimum, all of the BMPs should be required to have a system operator (typically a contract operator) consistent with the U.S. Environmental Protection Agency (EPA) Level 2 management program model. The operator performs specified operation and maintenance activities, verifies proper system function and reports back to the local health department or state. An operating or construction permit should also be required.

State-issued and renewable permits consistent with the EPA’s Level 3 management program model were encouraged but not deemed mandatory for reduction credit. Responsible management entities are also encouraged, and required for permeable reactive barriers. This would be Level 4 and 5 in the management program model.

These suggested reductions will be used in multiple runs of the model for the Chesapeake Bay watershed and based on results; the states and individuals will be encouraged to use the BMPs that seem to work best to reduce the nitrogen loading to the Bay.

If you are a professional working in the watershed area – covering parts of Pennsylvania, New York, Maryland, Delaware and Virginia – this may affect you through changes in both your local and state rules. That includes all aspects of managing onsite decentralized systems from design, siting, installation, operation and maintenance along with the management and treatment of septage. Any rule changes or enhancements made, as a result of the effort to reduce nitrogen to the Bay will then have a direct impact in those areas on the kinds of systems installed and the amount of maintenance that may be required.

STAY ON THE ALERT

The panel discussed at length the need for maintenance and long-term management. Each state currently has its own way of dealing with the issue, so there was no consensus on the panel about how to require and enforce the maintenance. But recognize that proposals will probably be made, and you should be alert about how those changes might affect your operation. The Chesapeake Bay is looked at as providing the model for what can be done across the country where nitrogen inputs to estuaries may be a problem.

If you are in the Midwest, think about the “dead zone” in the Gulf of Mexico caused by excess nitrogen delivered through the Mississippi River. If you are in New Mexico, consider the Rio Grande as it flows toward the Gulf. If you are in the Western high plateau area, think of the Colorado River as it flows to the Gulf of California across an international boundary. If you are in California, think of San Francisco Bay.

This panel focused specifically on reducing nitrogen; but another nutrient, phosphorus, came into play during the follow-up workshop. This is usually the limiting nutrient for algal growth in freshwater systems. Agriculture has begun dealing with phosphorus inputs through manure and other sources to look at reductions to freshwater systems. There have been calls to look again at phosphorus as it pertains to onsite systems. This could put us into a whole new area of concern for both system management and land application requirements.



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