Product/material recovery

Figure 10.7 shows the basic tradeoff to be considered as additional feed and product materials are recovered from waste streams and recycled. As the fractional recovery increases, the cost of the separation and recycle increases. On the dther hand, the cost of the lost materials decreases. It should be noted that the raw materials cost is a net cost, which means that the cost of lost materials should be adjusted to either... 

Essentially all the ammonium sulfate fertilizer used in the United States is by-product material. By-product from the acid scmbbing of coke oven gas is one source. A larger source is as by-product ammonium sulfate solution from the production of caprolactam (qv) and acrylonitrile, (qv) which are synthetic fiber intermediates. A third but lesser source is from the ammoniation of spent sulfuric acid from other processes. In the recovery of by-product crystals from each of these sources, the crystallization usually is carried out in steam-heated sa turator—crystallizers. Characteristically, crystallizer product is of a particle size about 90% finer than 16 mesh (ca 1 mm dia), which is too small for satisfactory dry blending with granular fertilizer materials. Crystals of this size are suitable, however, as a feed material to mixed fertilizer granulation plants, and this is the main fertilizer outlet for by-product ammonium sulfate. 

RO, primarily used ia the dairy iadustry, is expanding iato other areas of food processiag. RO can be used for a variety of operations, ranging from wastewater treatment and material recovery to clarification and concentration. Material recovery is advantageous for two reasons. By recovering valuable products, eg, proteias, from waste streams, profits can be iacreased while costs for waste disposal decreased. An excellent review of the different apphcations ofRO ia food processiag is available (9). 

Eddy-current separation is usually appHed to the removal of nonferrous metaUics from product streams containing nonmetaUic or nonmagnetic materials. These include appHcations such as material recovery facUities (MRF), eg, aluminum can recovery from commingled containers both prebumed... 

Location of Transfer Stations Whenever possible, transfer stations should be located (1) as near as possible to the weighted center of the individual solid-waste-produciion ares to be served, (2) within easy access of major arterial highways as well as near secondary or supplemental means of transportation, (3) where there will be a minimum of pubhc and environmental objection to the transfer operations, and (4) where construction and operation will be most economical. Additionally, if the transfer-station site is to be used for processing operations involving material recovery and/or energy production, the requirements for those operations must be considered. 

Recycling Use, reuse and recycling of wastes for the original or some other purpose, e.g. input material, materials recovery or energy production d j X ... 

On the other hand, the use of the total count method (7) largely forfeits the advantages which are inherent in the tracer method. Because the samples are extracted rather than assayed by combustion techniques, incomplete material recovery becomes a contributing factor. Furthermore, since the extracts are counted without preceding purification, the results cannot discriminate between residual gibberellie acid and possible degradation products. In spite of potentially increased sensitivity, the total count method offers no advantages over the bioassay or fluorometric procedures. 

Results. The results of this analysis are tabulated below. Contrary to natural growth processes, the distilling process (mashing, fermentation, distillation, and by-product feed recovery) destroyed considerable gibberellin, resulting in a material recovery of only 15%. 

With increasing production volumes of chemicals predicted for the next 20 years [242], the economic advantages of the costly application of recovery, reuse and recycling may prove limited unless regulatory controls are put in place. Chemical bans are now being enforced to ensure that material recovery and recycling targets are technically and economically achievable [243, 244]. 

R Conversion (%) Product Distribution (%) Material Recovery Ratio (ortho/ para)... 

The purpose of this subsection is to introduce the reader to the techniques and methods used to recover materials, conversion prodncts, and energy from solid wastes. Topics to be considered include (1) processing techniques for solid waste, (2) processing techniques for hazardous wastes, (3) materials-recovery systems, (4) recovery of biological conversion products, (5) thermal processes, and (6) waste-to-energy systems. 

Data related to heavy oils suggest that these products are very similar to the bitumen. This result is important because it shows that bitumen or very similar material can be produced during an in situ experiment. If the main product from recovery were bitumen and if the yield were high, most of the potential fossil energy value of a tar sand would be available above ground for additional processing. 

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