Recovery of Waste

FIGURE 9.3 A comparison of the heating value of plastics and conventional fuels. 

Recovery of plastics from MSW can be as a material resource (by material recycling), a feedstock (by thermal or chemical degradation), or as energy (by incineration or biological treatment). Different technical methods are available for each of 

Another recent waste management trend is to export waste, often sorted plastic waste, for reprocessing. The EU countries for instance export waste plastics (mainly polyethylene (PE) and PP) to member countries (mostly CJermany and France) as well as to Asia (mostly China) for reprocessing. 

FIGURE 9.4 Waste management options in United States (2010). The numbers in select 

TABLE 9.2 Breakdown of Different Classes of Plastics in MSW and their Recovery 

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In sulfuric acid production involving heat recovery and recovery of waste sulfuric acid, acids of various concentrations at high temperatures can be dealt with. Corrosion damage has been observed, for example, in sulfuric acid coolers, which seriously impairs the availability of such installations. The use of anodic protection can prevent such damage. 

Davos, 15th-19thMay 1995, paper 60. 8(13) COMBUSTION AND ENERGY RECOVERY OF WASTE PLASTIC BY INTERNALLY CIRCULATING ELUIDISED BED BOILER Tsukamoto K Kurihara K EBARACorp. 

The use is described of a foamed Styrol liquefaction treatment machine which has been developed as an environmentally acceptable method of recovery of waste foamed styrene.Details are given of the liquefaction treatment which consists of four processes crushing and removal of foreign substances heating, gasification and pyrolysis cooling and liquefaction and the recycling of resultant liquid as solvent for use in the first three processes. 

Lantagne and Velin [267] have reviewed the application of dialysis, electrodialysis and membrane cell electrolysis for the recovery of waste acids. Because of the new trends governed by environmental pressures, conventional treatment methods based on neutralization and disposal are being questioned. Membrane and electromembrane technologies are considered to be potential energy-efficient substitutes for conventional approaches. Paper mills will focus on the application of ion-exchange membranes namely dialysis, electrodialysis and membrane cell electrolysis for recovery of waste acids. 

Lantagne G, Velin AP, Overview of the application of dialysis, electrodialysis and membrane cell electrolysis for the recovery of waste acids, in ref (45a), and references therein... 

The Use of Solvent Extraction in the Recovery of Waste Michael Cox and Hans Reinhardt... 

Sack, W.A. Eck, R.W. Romano, C.R. Recovery of waste brines for highway applications. Proceedings of 40th Purdue Industrial Waste Conference, West Lafayette, IN, 1985. 

To overcome such hurdles, special devices have been proposed and tested, which are based on internal heat recovery of waste heat through the adoption of Swiss roll geometries, such as those reported in Figure 12.7 [52]. 

Anhydrous hydrogen chloride gas is used to produce phosphonium chloride, PH4CI, which is a flame retardant for cotton textiles. Other major apphcations include manufacture of a number of high purity metal chlorides, ammonium chloride, chlorosulfuric acid recovery of waste metals preparation of alkyl chlorides and chloroacetic acids and as a chlorinating agent in organic syntheses. 

J. H. Omstead and P. S. Grimes, "Heat Efficiency Improvements Through Chemical Recovery of Waste Heat", IECEC 729046 (1972). 

A final thought concerns the energy savings associated with the recovery of waste process heat for space heating purposes. In injection molding the heat removed from the mold by the chiller water is usually lost to the surroundings. This waste heat can be used to heat injection molding plants as reported by Haas (13). 

Figure 7 Schematic diagram of two-sectional countercurrent ion-exchange column operating at different temperatures to provide recovery of waste-free bromine from seawater.

Schmidt, W. Method for the Purification and Recovery of Waste Gelatin Using Diafilters. US Patent 5,945,001, Aug 62. 31, 1999. 

The evaporation process consumes relatively large amounts of energy. However, the recovery of waste heat from many industrial processes to provide a source of heat can alleviate the costs. Moreover, the equipment is sometimes highly specialized, and thus can be expensive. Another limitation is that, in some cases, prefreatment may be required to remove solids and/or bacteria that tend to cause fouhng in the condenser or evaporator. 

Wiles, C., Paper presented at the Fifth Annual Research Symp., Land Disposal and Resource Recovery of Wastes, U.S. Environmental Protection Agency, Office of Research and Development, held in Orlando, FL, March 1979, proceedings in press. 

A study by the Association of Plastics Manufacturers in Europe (APME) assessed the environmental impacts of mechanical and feedstock recycling and energy recovery of waste plastics. It was compared in terms of consumption of resomces and environmental emission pollution potential. The criteria of consumption of energetically exploitable resources and contribution to the greenhouse effect lead to the following order of preference for feedstock recycling and energy recovery processes ... 

Separation and recovery of waste materials is based on the same principles as those applied to minerals. 

Nowadays, Asahi, BASF, Bayer, Invista, Rhodia, Radici and Solutia use catalytic or thermal processes to destroy N2O. Recovery of waste heat from the exothermic abatement reactions is more effective with thermal systems due to their higher... 

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