Volume 18 | Number 2 | Summer 2006 | Environmental Issue

New Study Focuses on Developing Alternative Ways of Validating Storm Water Pollution Control Measures

The new study will evaluate the total suspended solids (TSS) benchmark in terms of containment area cleanliness, helping facilities to determine if optional best management practices (BMPs) such as this mechanical sweeper may be necessary.

Storm water runoff from industrial sites is a leading water pollution concern in the United States. This pollution occurs when rain picks up contaminants from a site’s surfaces and is then discharged directly into nearby rivers, streams, or lakes. In recent years, states have developed a 303(d) list of water bodies characterized as impaired, meaning they fail to meet federal water quality standards or the specific standards for their designated use. This has been done to help focus attention on why these waters are impaired and by what pollutant. Companies located near impaired streams with industrial activities that are a possible source of the identified 303(d) list pollutant(s) are required to sample their storm water discharge on a routine basis.

For meat and poultry operations, runoff containing manure solids is a major concern because of impairment from fecal coliform and possible reduced dissolved oxygen levels. However, no clear relationship has been established between poultry manure solids in discharged processing facility storm water and fecal coliform levels in impaired streams.

In lieu of in-stream monitoring, the industry has worked with regulators and interested advocacy groups to establish a benchmark value for discharged storm water based on total suspended solids (TSS). It is designed to help assess if facility storm water pollution prevention plans (SWP3) are minimizing the pollutant(s) of concern discharged. Exceeding the benchmark value is not a permit violation and does not of itself violate state water quality standards; however, in conjunction with other information, a violation of the permit or water quality standards may be considered as demonstrated.

Monitoring data collected by facilities will be analyzed as part of the Georgia Environmental Protection Division’s ongoing effort to confirm the correlation between fecal coliform and TSS (see page 3). With funding from the state’s Traditional Industries Program for Food Processing, researchers with Georgia Tech’s Food Processing Technology Division have also begun a study to evaluate the TSS benchmark in terms of containment area cleanliness.

How well impervious surfaces in containment areas (e.g., loading, unloading, and live animal holding) are cleaned directly impacts manure solids discharged at outfalls, explains John Pierson, a senior research engineer spearheading the Georgia Tech study. By characterizing wash waters and the cleaning approaches (e.g., cleaning frequency and type of cleaning equipment) used for the impervious surfaces, researchers can compile data representative of both concentrated and diluted storm water runoff. Pierson maintains that correlating these data sets will better define the relationship between best management practices (BMPs) outlined in a facility’s SWP3 and manure solids discharged in storm water, thus helping to understand correlations between fecal coliform and total suspended solids.

“We intend to establish a strategy that defines the procedure and tools needed to measure containment area impervious surface cleanliness. We believe the strategy will allow facilities to determine what BMPs work for their particular facility given their watershed considerations,” says Pierson.

“Addressing this critical need would streamline storm water management because both processors and regulators could better assess the performance of structural and operational BMPs and water quality,” adds Pierson.

During the project, researchers will work in the laboratory to develop and refine procedures for assessing methods for measuring impervious surface cleanliness. They will also work with industrial partners to perform on-site assessments of current operations and to characterize impervious surface areas. All activities will build on the existing requirements of the facility’s SWP3.

Specifically, Pierson says the team will gather samples of manure from containment areas and run several experiments to replicate discharged storm water. Experiments will include combining known amounts of manure and water with either a predetermined amount of mixing energy or water pressure.

“We are interested in establishing what should be expected so we can compare that with what occurs on-site. Every outfall is different in terms of its connection to the containment areas. We see the storm and that sampling event as the test, but our research is the homework to make sure processors are ready,” says Pierson.

In the future, the team also plans to review the BMPs developed for impervious surfaces for their applicability to pervious areas (e.g., gravel, grassy, or exposed soils).

“Our project builds on past and current research by developing the information and solutions needed to answer the mounting pressures and rising challenges faced by the poultry and food industries, municipalities, and others in managing storm water during the next several decades,” says Pierson.