Recycling Options

The recycling option is being utilized outside the United States. Whereas the technology of this option has been completely demonstrated ia the United States, the economics have not been favorable. Moreover, concerns have been raised as to the diversion of the plutonium to weapons use. Thus, the throwaway option is the only one ia use ia the United States as of this writing. 

Fig. 1. Municipal solid waste management system where ( ) indicates recycling options and (-), optional transfer.

Modification of Equipment. (/) Install equipment that produces minimal or no waste. 2) Modify equipment to enhance recovery or recycling options. (I) Redesign equipment or production lines to produce less waste. (4) Improve operating efficiency of equipment. (5) Maintain strict preventive maintenance program. 

Because of the problems with some recycling options, the ASTM committee on engine coolants is exploring a specification for recycled coolants. 

Figure 7.12 Structural representation of segregation, mixing and direct recycle options.

Figure 10.3 Recycling options in SMB systems, a) Recycling pump fixed with respect to the columns, b) Recycling pump fixed with respect to the zones (between Zone IV and Zone I), c) No recycling pump.

The range of measures applicable to control are summarized in Chapter 17. Recycling and recovery are potentially attractive measures hence solvents, mineral oils, metals, e.g. lead, copper, nickel, mercury, and glass are commonly recycled. However, recycling options generally depend upon favourable economics, particularly low collection costs. 

Solvent extraction shows effectiveness in the removal of organic wastes such as PCBs, VOCs, halogenated solvents, and petroleum wastes, but is less effective in removing inorganic compounds.39 The removal of organic contaminants depends on the nature of the extracting solvent. Organic bound metals can become a constituent of the concentrated waste, which is undesirable because it can restrict both disposal and recycle options. 

Percentage of savings in freshwater (relative to no reuse/recycle option) 46.15 52.56... 

Several options have been identified that refineries can undertake to reduce pollution pollution prevention options, recycling options, and waste treatment options. Furthermore, pollution prevention options are often presented in four... 

When pollution prevention and recycling options are not economically feasibly, pollution can still be reduced by treating wastes so that they are transformed into... 

Composting is the most common biological treatment option. It may be considered as a recycling option when the resulting compost is used as fertilizer or soil improver. Effects like increased water retention capacity and improved soil structure are ecological benefits that are of particular importance when soil erosion is a serious problem (for example in some Southern European countries). 

Treatment of waste should be considered only after source reduction and recycling options are fully addressed. Treatment includes methods for separation of the metals fraction from the wastes stream. This typically involves neutralization, precipitation, filtration and drying operations. Waste treatment, although often desirable and necessary, is not considered to be a waste minimization option by the USEPA... 

B —C reaction mechanism, we have recycle options for the fresh feed A only. Note, however, that if the reaction mechanism were of reversible reactions ... 

An example of how feedstock composition can influence the variation in product distribution and quality comes from application of the ABC (asphaltene bottoms cracking) hydrocracking process to different feedstocks (Tables 6-18, 6-19, 6-20, and 6-21) (Takeuchi et al., 1986 Komatsu et al., 1986). A further example of variations in product distributions from different feedstocks comes from the Mild Resid Hydrocracking (MRH) process (Table 6-22 Figures 6-14 and 6-15) (Sadhukhan et al., 1986). In addition, different processes will produce variations in the product slate from any one particular feedstock (Figure 6-14) and the feedstock recycle option adds another dimension to variations in product slate (Tables 6-23 and 6-24) (Munoz et al., 1986). 

Exergy savings and input for recycle option (see Figure 11.13). 

Part or all of three FCC products heavier than gasoline can be recycled from the fractionator back to the reactor the light cycle oil which at Toledo is a prime hydrocracker feed, the heavy cycle oil which is usually recycled, and the bottoms or slurry oil, part of which must be recycled to return entrained catalyst to the unit. The program offers six recycle options. For any option, the user specifies five out of the following eight recycle variables ... 

The recycling option is less preferable and should be resorted to after all feasible source reduction options have been explored and implemented. Onsite recycling has a higher priority than offsite recycling because reducing transportation, storage and other handling of hazardous wastes reduces the risks to health and the environment. 

The suitability of a waste for recycling depends mainly on the purity, concentration, and chemical form of the reusable material in the waste. For this reason, some waste materials must be treated before being recycled. This treat/ purify-then-recycle option is less desirable than direct in-process recycling/ reuse without treatment [20-23,25,50], as follows ... 

Onsite Use and Reuse In-process and other onsite recycling options may be made more feasible by the adoption of other source reduction practices, such as waste segregation to cut down contamination of materials (e.g., solvents, baghouse dusts, lubricating oils, or rinse waters). Reuse as raw material substitute for another process. 

The choice of recycling option depends primarily on the waste-disposal infrastructure already in place. The choice of recycling route will differ according to product group and region. The goal... 

F. Perugini, U. Arena and M. L. Mastellone, A life cycle assessment of mechanical and feedstock recycling options for management of plastic packaging wastes, Env. Progress, 24(2), 137-154 (2005). 

The modification of the plant should take into consideration the minimum or no-production of waste by installing new equipment to control the pollution. It is also possible to enhance the recovery or recycling options in the plants. 

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