IMPLEMENTATION OF ENVIRONMENTAL PERFORMANCE MEASURES FOR A PRETREATMENT PROGRAM
Introduction - Louisville and Jefferson County Metropolitan Sewer District (MSD) has been awarded an EPA Grant under Section 104 (b)(3) of the Clean Water Act to develop and evaluate innovative pretreatment program performance measures that are intended to lead toward a further
reduction of pollution from industrial sources. This paper will describe the preliminary conclusions from this 2.5-year study. This paper builds on the project approach presented at WEFTEC 99.
Project Objective - The objective of this project was to develop, implement, and assess
specific performance measures designed to measure the environmental impact of the pretreatment program in a selected sewershed. This measurement was made through development of relationships between commercial/industrial discharges, the collection system, the receiving stream, and the
treatment plant influent, effluent, and biosolids. The results of this study will be beneficial to other municipalities since the goal is to develop transferable performance measures.
Despite the fact that MSD's Pretreatment Program is considered successful, the only official measure
of success is a programmatic one. Even though there is approximately 1.4 million spent annually on implementation of the MSD pretreatment program, there is no direct measurement of the environmental impact. In fact, MSD's Stream Monitoring program indicates the streams in Jefferson County
suffer from pollution problems, most likely resulting from a variety of point and non-point sources. Therefore, MSD directed resources toward developing actual environmental performance measures for the pretreatment program. The Jeffersontown (J-town) system was selected as the initial testing
ground for this effort.
Project Approach - The approach for this project involved establishing project teams, gathering baseline information, developing performance measures, and modeling the system to predict the impact to the WWTP influent, effluent and biosolids from changes in
pollutant discharges. Finally the approach included implementing and assessing the proposed performance measures. MSD is also testing the transferability of the performance measures by evaluating a second sewershed.
Environmental Performance Measures - Environmental performance measures
were established with the full involvement of Stakeholders (environmentalists, industry, residents, etc). The performance measures compare treatment plant end products with environmental criteria. The proposed performance measures evaluate effluent quality, biosolids quality and maintenance
impacts. Effluent quality is compared to NPDES permit limits for conventional pollutants, NPDES permit limits for Biomonitoring, Water Quality Criteria for Metals and Organics, and NPDES requirement for aesthetics. Biosolids metals quality is compared to applicable code criteria. Control of
maintenance concerns at the WWTP and in the collection system is also monitored.
Trend Charting - Substantial data has been collected as a result of this project. The data has been incorporated into a comprehensive database. Trend charts have been prepared for visual measurement
of all performance measures. Trend charts have also been prepared for data other than the performance measures, for instance influent loadings and collection system contributions. These trend charts will aid in understanding the influences to treatment plant operation and effluent and biosolids
quality. Trend charts will be updated on a quarterly basis to provide an understanding of current trends.
Pollutants of Concern and Initiatives - “Pollutants of Concern” is a term coined to refer to the pollutants that require additional monitoring or control efforts
to ensure protection of the environment. MSD worked closely with the stakeholder group to develop the following criteria for identifying Pollutants of Concern:
Multiple exceedances of any environmental performance measure,
Increasing trend of a pollutant toward any performance measure,
Receiving stream background pollutant concentration near any water quality criteria,
Any parameter identified on the state 303
(D) List (impaired waters), or
Any parameter with a NPDES numerical limit.
Through the above definition, several pollutants of concern have been identified. MSD has planned initiatives to better regulate and control
the discharge of these pollutants. Some examples of initiatives include more regulatory oversight, pollution prevention efforts (industrial, commercial and residential), and public awareness efforts. Regulatory oversight may actually be reduced for those pollutants not of concern. Modeling
was used to demonstrate the impacts of modified levels of oversight.
Benefits - MSD has already realized significant benefits from this approach. These benefits include:
Understanding relative impacts of discharges with loading
data from the collection system,
Understanding stressors to the watershed,
Taking a proactive approach to improving water quality,
Improving incident response,
Expending limited resources to have the most impact on water quality (more oversight for industries discharging pollutants of concern, and less oversight for industries not discharging pollutants of concern).
Future Efforts - MSD
anticipates greater environmental health will result from the efforts of developing and tracking environmental performance measures and pursuing initiatives over and above the classic pretreatment program. The success of all initiatives will be evident by observing the trends for pollutants
of concern. MSD is transferring the project approach to their West County Sewershed. MSD hopes other municipalities and sewering authorities will find value in employing this pragmatic approach to the pretreatment program.
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