Refuse processing plants

Model experiment on the processes in a refuse incineration plant (Experiment 61) Determination of degree of pollution of water (Experiment 109)... 

Yet from these studies it follows that heat and mass transfer phenomena by no means can be ignored. Kung [b6] showed that among wood particles of 2, 0.2, 0.02 cm only the smallest ones showed a uniform temperature distribution. Hence in actual pyrolysis reactors the rate of conversion will usually be controlled by heat transfer. When the latter is very slow, as in the Destrugas process, plant operating capacity may be strongly affected by the moisture content of the refuse. 

Table X shows the running costs of the Dry Process PUROX System as well as the stoker incinerator. In Japan solid refuse treatment plants are operated by local municipalities and taxes and depreciation are not considered components of the running costs of solid refuse treatment plants. They, therefore, comprise electricity, water, chemicals, auxiliary fuel, labor, and maintenance costs. When a comparison is made on the basis of these costs, the Dry Process PUROX System is somewhat higher than the stoker incinerator.

The properties of refuse processed by the Tokyo plant shown in Table II differed widely from those of Kitakyushu. 

This chapter describes the unit operations that could be applied in a solid-waste processing plant aiming to recover recyclable materials, refuse-derived fuel, as well as products for further chemical or biological processing. The tailings from solid-waste processing are rejected to the landfill. 

More recently, tolling companies have been specifically formed to accept waste materials and industrial by-products for conversion into secondary raw materials. Waste processing facilities are set up in many countries in central or otherwise strategic locations at which, by combining the materials from different sources, large installations can be fed and maintained, thus lowering the conversion costs per unit mass. Municipal refuse combustion plants are typical examples in which agglomeration may... 

The first hydrochloric acid recovery plant in the world in a refuse incineration plant started operation in the Hamburg BorsigstraBe incineration plant in 1993 [7]. This plant produces high-quality hydrochloric acid from the washed out raw hydrochloric acid. The process is described by M. Schaub from SULZER CHEMTECH AG [8]. Hydrochloric acid which meets the appropriate standards commands considerable prices. 

This extensive usage of lead has given rise to widespread environmental contamination. In rural areas ambient lead levels are usually below 0.2 jug/m in remote areas of the world one or two orders of magnitude below this, and in urban areas one order of magnitude above, with values up to 10 jUg/m not infrequently recorded in dense traffic. Over one-half and up to 90% of the airborne lead is derived from vehicle exhausts, the remainder from refuse incineration, fossil fuel combustion and from industrial sources such as smelters, iron and steel works and lead processing plants. 

Refuse-Derived Fuel. Many processing faciUties divert a portion of the material that is not recovered for recycling to waste-to-energy plants, also referred to as resource recovery faciUties, where the material is employed as fuel. The processes involved in the production of refuse-derived fuel (RDF) are outlined in Figure 4 (23). Nine different RDFs have been defined, as Hsted in Table 3 (24). There are several ways to prepare RDF-3, which is perhaps the most popular form and is the feed used in the preparation of densified refuse-derived fuel (d-RDF). AH forms of RDF are part of the broader set of waste-derived fuels (WDF), which includes various waste biomass, eg, from silvaculture or agriculture (see Fuels frombiomass Fuels fromwaste). 

Additions of new flocculants after conventional thickening produce further dewatering of mineral slimes. A clay flocculated with polyacrylamides and rotated in a dmm can produce a growth of compact kaolin pellets (84), which can easily be wet-screened and dewatered. A device called a Dehydmm, which flocculates and pelletizes thickened sludges into round, 3-mm pellets, was developed for this purpose. Several units reported in commercial operation in Japan thicken fine refuse from coal-preparation plants. The product contains 50% moisture, compared with 3% soflds fed into the Dehydmm from the thickener underflow (85). In Poland, commercial use of the process to treat coal fines has been reported (86), and is said to compare favorably both economically and technically to thickening and vacuum filtration. 

Contamination by flies may occur directly in a factory, especially if material is allowed to stand unprotected for long periods while being held for processing. Failure to dispose of refuse promptly, particularly outside the plant, frequently creates ideal breeding and feeding places for these pests. Under such circumstances, parts of the adult vinegar fly, its larvae, or eggs, when found in the comminuted product, provide definite evidence of careless and insanitary operations. 

At the semiconductor plant, a small amount of hydrofluoric acid was used in the processing. After neutralization, it was discharged into the large flow of water from the plant. When waste water in the area near the plant showed fluoride levels well in excess of the permissible 5ppm, the manufacturer became suspect. Refusing to believe that he could cause such contamination, he called in a consultant, who calculated that the water from this plant could contain as much as 60 ppm fluoride. This still sounded impossible to the manufacturer, but analysis confirmed the calculated result. Steps were soon taken to correct the situation. 

Municipal Sewage Treatment Plant. The reactors were batch-fed daily an RDF (refuse derived fuel) processed MSW feedstock obtained from Future Fuels Inc. in Thief River Falls, MN. The processed MSW feed contained 52% of dry weight (DW) cellulose, 20% lignin-plastics, 2% ash, and 26% acid-detergent solubles (% DW as determined by the acid-detergent-fiber assay (63)). The MSW feedstock was added to a nutrient solution at 5% w/v for daily feeding as previously described (55). 

Harada, Y., Inoko, A., Tadaki, M. and Izawa, T. (1981) Maturing process of city refuse compost during piling. Soil Science and Plant Nutrition 27, 357-364. 

Table 5-1 lists the air releases from facilities in the United States that produce, process, or use nickel and its compounds, according to the 1993 TRI (TRI93 1995). These releases, totaling 285,857 pounds (129,935 kg), constitute 37.5% of the environmental releases reported in the TRI. However, since the TRI does not include emissions from power plants and refuse and sludge incinerators, its estimate of U.S. nickel emissions is incomplete. 

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