Containers, waste reduction

Additionally, the EPA pubhshes a newsletter entitled Pollution Prevention News that contains information including EPA news, technologies, program updates, and case studies. The EPA s Risk Reduction Engineering Laboratoiy and the Center for Environmental Research Information has pubhshed several guidance documents, developed in cooperation with the California Department of Health Services. The manuals supplement generic waste reduction information presented in the EPA s Waste Minimization Opportunity Assessment Manual (Ref. 9). 

In some cases the methods may be combined. Examples would include the biotechnological precipitation of chromium from Cr(VI)-containing wastes from electroplating factories by sulfate reduction to precipitate chromium sulfide. Sulfate reduction can use fatty acids as organic substrates with no accumulation of sulfide. In the absence of fatty acids but with straw as organic substrate, the direct reduction of chromium has been observed without sulfate reduction [43]. 

Waste segregation is an important step in waste reduction. Process wastewaters containing specific pollutants can often be isolated and disposed of or treated separately in a more technically efficient and economical manner. Highly acidic and caustic wastewaters are usually more effectively adjusted for pH prior to being mixed with other wastes. Separate equalization for streams of highly variable characteristics is used by many plants to improve overall treatment efficiency [7]. 

Recently, a new porous crystalline matrix ( Gubka ) has been prepared on the basis of fly ash from power stations to incorporate complex ACT-containing wastes by means of repeated saturation-drying-calcining cycles. This matrix can accommodate up to 50 wt% nitrate salts (after drying) and 35 wt% calcine. The waste-loaded material can be consolidated by hot pressing with a 35% volume reduction (Aloy et al. 2000 Tranter et al. 2002). 

The restrictions on the land disposal of many wastes have increased the cost of hazardous waste disposal. The land disposal restrictions that affect metal fabricators have been in effect for several years. For example, the restrictions on the land disposal of liquid wastes containing toxic metals and/or acids began on January 1,1984 (Section 66905 CCR). These restrictions have caused increases in disposal costs since these wastes now require some form of treatment prior to land disposal. These increased waste disposal costs are viewed as a driving force for the metal finishing industry to implement waste reduction technologies. 

The audit program employs contractors for completion of waste audit studies of specific industries. After the studies are completed a final report is then generated, containing recommendations and conclusions for waste reduction. The final report is used as a source document for developing the fact sheets and the WRAM for use by small quantity generators (SQG). Currently 19 different industry waste audit studies have been completed. 

The waste reduction options included within the study were also incorporated into the checklist. A two column format was chosen to provide more information on the proposed option. The left column contains the question from the checklist and the preferred answer, which is highlighted. The right column provides an explanation of the potential benefit associated with the option, or a description of the option. The options addressed by the checklist were then tabulated and are included in Appendix A. 

After Section One of the manual (the checklist) has been completed and responses have been recorded on the implementation potential worksheets, Section Two can be used to prioritize the selected options. Section Two contains tables of the waste reduction opportunities discussed in the checklist. The tables, consisting of... 

Additional reductions in the amount of hazardous filter cake sludge produced were achieved with three process chemistry substitutions completed in September 1988, which eliminated a major source of chrome-containing wastes in the metal plating production facility. The initial substitutions replaced a chromic acid / nitric... 

Regulatory barriers. Existing regulations that have created incentives for the control and containment of wastes are at the same time discouraging the exploration of pollution-prevention alternatives. Moreover, since regulatory enforcement is often intermittent, current legislation can weaken waste-reduction incentives. 

A third emission reduction choice is to remain with the existing front end process, which continues to produce a sulfur dioxide-containing waste gas stream, and move to some system which can effectively remove the sulfur dioxide from this waste gas before it is discharged. Many methods are available, each with features which may make one more attractive than the others for the specific sulfur dioxide removal requirements (Table 3.8). Some of the selection factors to be considered are the waste gas volumes and sulfur dioxide concentrations which have to be treated and the degree of sulfur dioxide removal required. It should be remembered that the trend is toward a continued decrease in allowable discharges. The type of sulfur dioxide capture product which is produced by the process and the overall cost are also factors. Any by-product credit which may be available to offset process costs could also influence the decision. Finally, the type of treated gas discharge required for the operation (i.e., warm or ambient temperature, moist or dry, etc.), also has to be taken into account. Chemical details of the processes of Table 3.8 are outlined below. 

A second level of analysis for waste reduction in chemical reactors considers the fact that hazards associated with many wastes are due to trace contaminants. For example, if a reactor produces a by-product stream that is considered a waste only because it contains a trace of a chlorinated dibenzodioxin, then eliminating the trace level of dioxin may allow the by-product stream to be used productively. Eliminating the production of very hazardous trace-level components may involve far different reactor designs than those used for maximizing selectivity. These types of improvements are still in their infancy and will require significant fundamental research to become practical. They are discussed in more detail in Section IV. 

Finally, integrating chemical reaction and separation in a single vessel offers opportunities for waste reduction. As an example of this strategy, consider the synthesis of methyl-tert-butyl ether (MTBE). Two processes are in common industrial use in the synthesis of MTBE from methanol and isobutylene. In one process, a series of fixed-bed catalytic reactors send a mix of product, unreacted methanol, and unreacted isobutylene to a series of separation devices. In an alternative process configuration, the feed materials are sent to a distillation column that contains a series of catalytic beds. The processes are contrasted in Fig. 17. There are several advantages to the catalytic distillation configuration ... 

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