Posttreatment Handling

Once again, there are statistical considerations with regard to random fluctuations in the mutant population. To achieve the aforementioned 10% precision in a healthy culture with a 5 X 10 mutant fraction (background), at least 100/5 Xl0 = 2.0xl0 cells must be passaged with each dilution i.e., 40 ml at 5 X 10 cells/ml is a minimum culture volume. 

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Health, safety and environmental factors have had a significant impact on the treatment process and particularly process control. Two examples serve well here the move within the European industry from organic solvent based treatments for organic biocides to water-based treatments, and the very specific requirements for posttreatment handling of the treated wood. In the second example, it is the leaching of unfixed preservative as a result of rainfall on freshly treated material, and the resulting concerns over environmental impact which have driven the development of processes and practices such as steam fixation, or rapid drying of treated wood. 

Steam distillable impurities in the process stream are carried over with the product water and must be handled by pre- or posttreatment, if they cannot be tolerated. 

Overall Some posttreatment of No apparent secondary Standard offgas treatment Wastes are handled... 

Pretreatment and Posttreatment - Some materials may require pretreatment processing to prepare the material for extraction or post-treatment of the residue after extraction is completed. Material handling systems such as conveyors and product silos must be designed with these considerations in mind. 

Recommendation Ideally, the binary precursors methyl-phosphonic difluoride (DF) and ethyl-2-diisopropylamino-ethyl methylphosphonite (QL) stored at Pine Bluff Arsenal should be destroyed directly, either by burning in the Pine Bluff Chemical Destruction Facility incinerator or by plasma arc treatment. If these facilities cannot handle the fluorine-rich DF destruction products, the committee recommends that on-site neutralization followed by oxidative posttreatment of the neutralents be developed. The easiest posttreatment may be shipment to a commercial incinerator capable of dealing with high levels of fluorine (Recommendation 3-2). 

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