Solid final disposal

Functional Elements The activities associated with the management of solid wastes from the point of generation to final disposal have been grouped into the functional elements identified in Fig. 25-59. By considering each fundamental element separately, it is possible to (1) identify the fundamental element and (2) develop, when possible, quantifiable relationships for the purpose of making engineering comparisons, analyses, and evaluations. 

Site Selection Factors that must be considered in evaluating potential solid-waste-disposal sites are summarized in Table 25-71. Final selection of a disposal site usually is based on the results of a preliminary site survey, results of engineering design and cost studies, and an environmental-impact assessment. 

The sources of solid wastes per se are summarized in Tables 16.1 and 16.4.) However, dealing with any of them will involve some combination of the activities shown in Figure 16.2, i.e. collection, segregation and identification, processing, recycling, transport and final disposal. 

For wet ESPs, consideration must be given to handling wastewaters. For simple systems with innocuous dusts, water with particles collected by the ESP may be discharged from the ESP system to a solids-removing clarifier (either dedicated to the ESP or part of the plant wastewater treatment system) and then to final disposal. More complicated systems may require skimming and sludge removal, clarification in dedicated equipment, pH adjustment, and/or treatment to remove dissolved solids. Spray water from an ESP preconditioner may be treated separately from the water used to wash the ESP collecting pipes so that the cleaner of the two treated water streams may be returned to the ESP. Recirculation of treated water to the ESP may approach 100 percent (AWMA, 1992). 

In future, the developments in hydrometallurgy will need to be concerned more with environmental problems associated with pertinent processes. Hydrometallurgical processes produce a variety of waste liquors and unwanted solid products which must be treated before their final disposal. There are two main objectives in such waste treatments the first is to recover valuable impurities and unused reagents from the solutions and the second is to ensure that the release of associated materials does not pollute the environment to an unacceptable extent. 

Another important implication is that highly permeable soil liners generally have defects, such as cracks, macropores, voids, and zones, that have not been compacted properly. One opportunity to eliminate those defects is at the time of construction. Another opportunity arises after the landfill is in operation, and the weight of overlying solid waste or of a cover over the whole system further compresses the soil. This compression, however, occurs only on the bottom liners, as there is not much overburden stress on a final cover placed over a solid waste disposal unit. This is one reason why it is more difficult to design and implement a final cover with low hydraulic conductivity than it is for a bottom liner. Not only is there lower stress acting on a cover than on a liner, but also the cover is subjected to many environmental forces, whereas the liner is not. 

Critics of waste incineration argue that these plants often create more environmental problems than they solve. They point out, for example, that incinerators are a major source of dioxin, mercury, and halogenated hydrocarbon release into the atmosphere. In addition, incinerators are very expensive to build and to maintain, and they provide fewer jobs to members of the surrounding community than other methods of solid waste disposal. Also, companies have a dismal record of siting incinerators in disadvantaged communities, where residents suffer the worst consequences of incinerator use. Finally, waste-to-energy incinerators are of little value in tropical and subtropical countries, where the cost of plants and the availability of additional energy sources make them impractical. 

Mettler et al. found that their original procedure was not very convenient for large-scale production of the malonate intermediate 16. Safety precautions required to handle excess solid potassium cyanide were both difficult and expensive. To compound the problem even further, a large amount of Ti02-pyridine complex was generated in the first step of this process. This solid waste material required special purification treatment before its final disposal. 

Immobilization is the process of incorporating waste into a matrix material for solidification, or directly into a storage and/or final disposal container. More specifically, solidification can be defined as encapsulation of a waste in a solid of high structural integrity (Freeman, 1998). At the same time, the goal of the solidification process is the stabilization of the waste, which means that the risk posed by the waste is reduced by converting it into a less soluble and less mobile form (Freeman, 1998). 

Solid wastes are treated in a solid waste disposal area to reduce their volume and or toxicity prior to final disposal in a secured landfill. Combustible wastes can be incinerated in a slagging rotary kiln to reduce volume and toxicity. 

Nonhazardous waste dust may be generated from two sources, the facility dust collection system or from spills in the storage or production areas. Dust that is not used to produce a wide specification colorant product is usually encapsulated with virgin and/or purge resin and sent to a qualified solid waste landfill for final disposal. The average annual waste dust landfilled per facility is approximately 4.5 tons. However, the facility generating the highest annual quantity of dust (20.6 tons) ships this material to an industrial waste incineration facility. 

Under RCRA, waste producers are required to take a cradle to grave approach to waste management. The producer of the waste is legally liable from the moment that waste is produced until its final disposal. A waste generator must identify waste material as hazardous waste if it is on a regulatory list or has a characteristic of flammability, toxicity, corrosivity, or reactivity. Once a material has been identified as hazardous waste, it must be clearly labeled and tracked when in transport. The waste must be treated in special facilities to low levels of contaminants. The final residual solid material, for example, incinerator ash, must be disposed into a registered hazardous waste landfill. 

The use of nuclear power as energy source is determined by the safe handling and deposition of the nuclear waste. High active waste solutions must be transformed into stable solid form which is suitable for final disposal. The separation of the actinides from the waste before its solidification (e.g. vitrification) is advantageous (or may be even necessary) from two points of view ... 

Liquid waste streams with a high-suspended solids content can be cleaned up by solids removal in clarifiers, thickeners, and liquid cyclones and by accelerated settling by inclined Chevron settlers or the like [73]. For waste streams with very finely divided solids in suspension (i.e., less than about 100 pm) dissolved air flotation techniques have been shown to be more efficient than methods employing sedimentation. Final dewatering of the sludges obtained may be carried out on a continuous filter or a centrifuge. The clarified water product can be accepted for more potential options of reuse or final disposal options than untreated water, and the separated solids may be burned or discarded to landfill, as appropriate [74]. 

The components of most refinery liquid waste streams are recovered and reused, whenever feasible. Unfortunately, some of these, such as aqueous caustic phenolic or caustic sulfidic wastes, do not lend themselves readily to reuse. Deep well disposal, incineration, or precipitation in some manner and landfilling of the separated solids are the measures used in these instances. Raising the concentration of brine streams by reverse osmosis before discharge can help decrease final disposal costs by decreasing the waste volume [78]. 

Hughes, G.M., Schleicher, J.A. and Cartwright, K., 1976. Supplement to the final report on the hydrogeology of solid waste disposal sites in northeastern lllinoise. Ill. State Geol. Surv., Environ, Geol. Note 80. 24 pp. 

The specific volume of calcine will be about 40 liters/MT of heavy metal for combined HLW and MLW, corresponding to that to be expected from the AGNS plant. For final disposal, the product from the fluidized-bed calcination will have to be consolidated by melting with a glass flux. If it is to be stored for extended periods directly in sealed canisters, the calcined solid will have to be stabilized (denitrated, dehydrated) at approximately 900 C. 

Thermal plasmas can be effective in compaction and destraction of liquid and solid hazardous wastes (Watanabe, 2003), including treatment of radioactive wastes by plasma incineration and vitrification for final disposal (Tzeng et al., 1998), plasma compaction... 

This chapter applies to all locations involved in the storage or use of chemicals and chemical products (see def). An important point of this chapter is that these consolidated requirements apply until the time the chemicals are identified as solid waste for final disposal (see def.) under the provisions of the Resource Conservation and Recovery Act (RCRA). 

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