Incineration of solid wastes

The efficient and effective disposal of solid waste is a major problem faced by all industrialized societies. At present, urban communities in the United States produce refuse at a rate of about 2.2 kg (5 lb) per person per day and this quantity is expected to increase in the future. 

The average per capita refuse production in the U.S. is about 2 kg (4 lb) per day, while the corresponding figure for Western Europe is about 1 kg/day [96]. By definition, refuse is inherently a heterogeneous substance that even 

Several methods have been used for the characterization of refuse. Some of these have been derived from the techniques employed for the characterization of solid fuels such as the proximate and ultimate analyses. The reader will recall from the previous section that by proximate analysis we mean the moisture, volatile, fixed carbon, and ash content of the refuse. The ultimate analysis gives the actual chemical composition of the refuse. Still another classification which is frequently employed provides a breakdown of the refuse components according to their origin, viz., glass, leather, paper, etc. 

A typical refuse composition shown in Table 8.10 indicates that in the U.S., paper, yard waste, and food waste are the predominating refuse components. Table 8.11 shows the mean composition of municipal refuse in the U.S. the standard deviations, also listed, indicate the variations that one might expect. 

There are three basic methods available for the disposal of refuse dumping, sanitary landfill, and incineration. 

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Incineration with Heat Recovery Heat contained in the gases produced from the incineration of solid wastes can be recovered as steam. The low-level heat remaining in the gases after heat recoveiy can also be used to preheat the combustion air, boiler makeup water, or solid-waste fuel. 

There is a large class of industrially important heterogeneous reactions in which a gas or a liquid is brought into contact with a solid and reacts with the solid transforming it into a product. Among the most important are the reduction of iron oxide to metallic iron in a blast furnace the combustion of coal particles in a pulverised fuel boiler and the incineration of solid wastes. These examples also happen to be some of the most complex chemically. Further simple examples are the roasting of sulphide ores such as zinc blende ... 

Drying Ethylene dichloride synthesis Roasting of sulfide ores Incineration of solid waste... 

Zhang and Itoh (2006) described a low-cost, environmentally friendly adsorbent for As(III) photocatalytic removal, formed by a mixture of Ti02 and slag-iron oxide obtained from an incinerator of solid wastes. Arsenite is first oxidized to arsenate in a fast process, followed by a slow adsorption of arsenate, although the material shows an adsorbent capacity higher than that of pure anatase. 

Another alternative to landfill disposal for many areas has been the incineration of solid wastes. This method is often criticized because it has the potential of polluting the air, and the residual ash still has to be buried in a secure landfill. Dumping in the ocean has also come under attack by environmentalists who cite pollution of marine ecosystems and destruction of recreational beaches as reasons against ocean dumping. 

Rubel, F. H., Incineration of Solid Wastes, pp. 56-57, Noyes Data Corp.,... 

Incineration of solid waste Bubbling/turbulent bed regime... 

Mechanisms of chemical contamination in the environment has developed mainly due to the development of complex sampling methods and very sensitive techniques and instruments for chemical analysis. Without the aid of these laboratcay instruments capable of detection of very low detection limits, many examples of the environmental contamination risks would remain unveiled today. Example include problems of pesticide residuals in a water body the dioxins, furans and TCDD compounds in air originating from the incineration of solid wastes containing chlorinated polymers are all detected in ecosystems by means of such sophisticated research techniques and equipment. By... 

Combustion is a process of rapid exothermic chemical reaction between a combustible substance and oxygen. In principle, the end products of combustion are oxides of the elements in the substance (e.g. waste feed). Combustion is generally a gas phase phenomenon, with the exception of combustion of solid carbon which, in forms such as soot and char, reacts heterogeneously. Incineration of solid wastes primarily involves the combustion of vapours and gases resulting from the thermal decomposition of the waste feed, and the combustion of the residual char. 

These new developments were motivated to a great extent by the societal and economic importance of gas-solid reaction systems due to their relevance for a broad range of processing operations, including iron oxide reduction, the combustion of solid fuels, the desulfurization of the fuel gases, and the incineration of solid wastes. 

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