Metal Finishing Guide Book


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Steps 8 and 9 — Data Collection and Analysis. The SAP will specify the what, where, and how of collecting representative waste samples. The term representative here is very important in that above all else the samples collected need to truly represent the waste. Factors such as waste variability over time, production variables, waste treatment variability, and potential for system upsets are all important to account for in your approach to data collection. Data analysis can be quite complicated or rather straightforward. Typically if you have a large dataset, say, greater than 15 samples, you can perform fairly robust statistical evaluations using some rigorous data mining efforts. The agency should be consulted beforehand regarding what approach they will endorse regarding data analysis. If your budget will only accommodate a small sample size, say, six (6) samples, the agency will require that for a given analyte the maximum observed value should be used versus, for instance, a mean value or some other statistically derived exposure endpoint. Once you have analyzed the data and arrived at an exposure point concentration for each of the constituents of concern, you are ready to run the DRAS model. The Delisting Risk Assessment Software (DRAS) model was developed by EPA Region 6 and improved and modified by Region 5. DRAS performs a multi-pathway and multi-chemical risk assessment to assess the acceptability of a petitioned waste to be disposed into a Subtitle D landfill or surface impoundment. DRAS executes both forward- and back calculations. The forward calculation uses chemical concentrations and waste volume inputs to determine cumulative carcinogenic risks and hazard results. The back-calculation applies waste volume and acceptable risk and hazard values to calculate upper- limit allowable chemical concentrations in the The DRAS 3.0 model is available on EPA Region 5's website. The results of running the DRAS model ultimately determine whether you will be able to get your waste delisted. If you pass the DRAS model then you incorporate your findings into your petition. If you fail the DRAS model (i.e., you exceed a DRAS calculated limit for a given chemical) you need to consult with the agency to determine next steps. Steps 10, 11, and 12 — Preparing and Submitting the Petition and Publication in the Federal Register. The culmination of all of the previous steps is the preparation of a delisting petition. The petition is the petitioner's main product for delivery to the agency for review and consideration. The major sections of a delisting petition are outlined in Table 4. A typical delisting petition will be well over 500 pages and frequently over 1,000 pages long. The petition is aimed at providing all of the information necessary for the agency to make an informed decision regarding the requested delisting for the waste. CONCLUSIONS For metal finishing plants with significant generation rates of hazardous wastes, it may be wise to look at a hazardous waste delisting as a way to avoid high disposal costs. Once a facility is delisted the subject waste can be disposed in a Subtitle D landfill where the costs are frequently 4-8 times cheaper. Further, many of the headaches that go along with handling hazard687

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