January-February 2003

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Nutrient Trading: A Bridge Over Troubled Water?

Pollutant allowance trading systems offer a new opportunity for improving water quality. How enforceable are they?

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By April Grippo

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Despite considerable reductions in pollution since the passage of the Clean Water Act (CWA), today 40% of United States waters still fail to support one or more of their designated uses. Though the number of discrete dischargers, such as industries and municipal wastewater treatment plants, has grown substantially through the years, technology has afforded these dischargers the capacity to make large reductions in the individual levels of pollutants they output. Meanwhile, runoff from nonpoint sources, including urban development and agriculture, has also added to the sheer quantity of pollutants entering water bodies. These nonpoint sources, by "virtue" of their nonpermitted status with little or no required pollutant reduction, have simultaneously increased their share of the actual pollutant levels found in many water bodies. This is particularly true for such nutrients as nitrogen and phosphorus.

According to USEPA, excessive nutrient loading is the third leading cause of water-quality impairment in the US. Although nitrogen and phosphorus loading was formerly linked to sewage treatment plants, nitrogen from wastewater treatment plants has declined dramatically in treatment-plant effluent with the implementation of biological nutrient removal technology. Phosphate bans on such household items as detergents and cleaners have also led to influent phosphorus reductions in wastewater treatment plants. Nutrient enrichment is now principally attributed to nonpoint sources, particularly nitrogen loadings from urban development, septic systems, and agricultural facilities. This problem is exacerbated throughout watersheds as development and agriculture spreads farther into the formerly undisturbed countryside.

In an effort to reclaim nutrient-impaired waters, total maximum daily loads (TMDLs) are being developed that require considerable reductions in nitrogen and phosphorus. For areas where impairment due to nutrient enrichment is extensive, a number of approaches will be needed to yield the necessary reductions. Success in reducing nutrient loads from nonpoint-source pollution in the long run, however, will depend on development of low-cost, innovative methods that can effectively cut pollution without excessively constraining current and future land uses and development and agricultural practices. Nutrient trading is gaining popularity as a method that fits the bill.

EPA: Laying the Foundation

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In 1996, EPA issued an Effluent Trading in Watersheds Policy and Draft Framework for Watershed-Based Trading. Following that, the agency funded a number of demonstration trading projects, including the Chesapeake Bay Program, believing that the lessons and methods from these programs would be valuable in other efforts to restore water quality. Although some attention was given to these projects by dischargers with high total suspended solids and other chemical pollutants, effluent trading did not advance as expected.

In May 2002, EPA renewed its support for the development of a market-based trading system with a proposed water-quality trading policy. This policy encourages states to develop trading programs that implement CWA requirements in more flexible ways. Programs are intended to be consistent within existing regulatory frameworks - including National Pollution Discharge Elimination System (NPDES) regulations and TMDLs.

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