Release mitigation

This section describes four additional techniques for mitigating releases of hazardous substances into the atmosphere. In addition to water, both steam and compressed air can be used to promote the movement of air to dilute a hazardous material. Foam can be used as a scrubbing medium to entrap a hazardous material in its structure. Foam scrubbing is often effective for materials that are soluble in water, or that are highly reactive with an additive contained in the foam. Lastly, dry powders can be used to capture a reactive chemical released into the air. 

For each of the postrelease mitigation techniques examined a description of the consequences of the unmitigated release will be presented first, followed by the mitigated release. The results have been tabulated and shown in figures. 

In each SCB a multi-stage filter will be installed on the process vacuum line. The filter will be configured appropriately for specific process operations. For Mo-99 processing, the filter will consist of an iodine pre-filter, a moisture trap, followed by a charcoal filter. The effluent from the process vacuum is exhausted to the ventilation system, which contains appropriate filters to mitigate releases. 

The maximum potential dose consequences for the unmitigated release are approximately 0.08 mrem and the estimated maximum potential dose consequences for a mitigated release would be less than 0.008 mrem, both well below the evaluation guideline of 25 rem. 

Richardson, D., Felgate, H., Watmough, N., et al. (2009). Mitigating release of the potent greenhouse gas N2O from the nitrogen cycle Could enzymic regulation hold the key, Trends Biotechnol., 27, pp. 388-397. 

Pollution/Pollutants. In this report, the terms pollution and pollutants refer to all nonproduct outputs, irrespective of any recycling or treatment that may prevent or mitigate releases to the environment. 

Effectiveness ofi Water Spray Mitigation Systems fior Accidental Releases ofiHydrogen Fluoride, Summary Report, National Technical Information Service, June 1989. 

The nephrotoxic amino acid, lyskioalanine [18810-04-3] formed upon alkaline treatment of proteki, was reported ki 1964 (108). Its toxicity seems to be mitigated ki proteki ki that it is not released by normal digestion (109). Naturally occurring new amino acids, which can be classified as protekiaceous or non-protekiaceous, can, as ki the case of those from some legumes, show a remarkable toxicity (110). Eor the details of amino acid toxicity, see reference 6. Enzyme inhibition by amino acids and thek derivatives have been reviewed (111). 

Instrumentation (Arthur D. Little, Inc., and Levine, 1986.) Instrument systems are an essential part of the safe design and operation of systems for storing and handling highly toxic hazardous materials. They are key elements of systems to eliminate the threat of conditions that could result in loss of containment. They are also used for early detection of releases so that mitigating ac tion can be taken before these releases result in serious effects on people in the plant or in the public sector, or on the environment. 

SOURCE Adapted from Prugh aud Johusou, Guidelines for Vapor Release Mitigation, AlChE, New York, 1988... 

This is a very small release rate and demonstrates that it is much more effective to prevent the release than to mitigate it after the fact. 

Process Safety A discipline that focuses on the prevention and mitigation of fires, explosions, and accidental chemical releases at process facilities. Excludes classic worker health and safety issues involving working surfaces, ladders, protective equipment, etc. 

Critical Equipment Equipment, instrumentation, controls, or systems whose malfunction or failure would likely result in a catastrophic release of highly hazardous chemicals, or whose proper operation is required to mitigate the consequences of such release. (Examples are most safety systems, such as area LEL monitors, fire protection systems such as deluge or underground systems, and key operational equipment usually handling high pressures or large volumes.)... 

Adequate distance frequently serves to mitigate the consequences of an accidental release of chemicals, e.g. a flammable liquid spillage or toxic gas escape. 

Guidelines for Post Release Mitigation in the Chemical Process Industry (1997)... 

Harris, N. C. (1987). Mitigation of Accidental Toxic Gas Releases. Proceedings of the International Symposium on Preventing Major Chemical Accidents, February 3-5, 1987, Washington, D. C., ed. J. L. Woodward, 3.139-3.177. New York American Institute of Chemical Engineers. 

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