Disposal of Solid Waste

Only general guidelines are given here for disposal of solid wastes. The actual scheme shall be submitted to the statutory authorities in the country and implemented only as per their directives. 

If the analysis of solid waste meets the guidelines given by State Pollution Control Authority (for chlorides, sulphates, phosphates, heavy metals) and has low calorific values, then it can be neutralised by the addition of lime, and immobilised by the addition of sodium silicate, fly ash, and portland cement as binding agent. It is now to be tested for oozing out of leachate when it is made wet (due to rainwater in practice), and can then be sent to the secured landfill site. This site is selected away from water bodies such as lakes, rivers, weUs, and groundwater sources for drinking water. 

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LandtiUing of Solid Wastes Landfilling involves the controlled disposal of solid wastes on or in the upper layer of the earth s mantle. Important aspects in the implementation of sanitary landfills include (1) site selection, (2) landfimng methods and operations, (3) occurrence of gases and leachate in landfills, (4) movement and control of landfill gases and leachate, and (5) landfill design. The landfilling of hazardous wastes is considered separately. 

Figure 16.2 Three basic techniques - treatment, storage, conveyance - to effect recycle or disposal of solid waste either on- or off-site.

Sanitary landfilling is an acceptable and recommended method for ultimately disposing of solid wastes. This method has sometimes been confused with waste disposal on open and burning dump sites, but this is a misconception. The sanitary landfill is an engineered landfill that requires sound and detailed planning and specification, careful construction, and efficient operation. In essence,... 

A sanitary landfill is defined as a land disposal site that applies an engineered method of disposing of solid wastes on land in a manner that minimizes environmental hazards by spreading the solid wastes to the smallest practical volume, and applying and compacting cover material at the end of... 

Landfill methods are considered the most economical and environmentally acceptable way of disposing of solid wastes throughout the world. Even with the implementation of waste reduction, recycling, and transformation technologies, disposal of residual solid waste in landfill will still remain an important component of an integrated solid waste management strategy.4... 

Table 1 indicates primary pollutant sources and waste modes, and Table 2 indicates the primary and secondary sources and associated pollutants. The primary sources of soil contamination include land disposal of solid waste sludge and waste-water industrial activities and leakages and spills, primarily of petroleum products. The solid waste disposal sites include dumps, landfills, sanitary landfills, and secured landfills. 

The major release of chlordecone to sediments, however, occurred indirectly as a result of waste water discharges, runoff of contaminated soil, and direct disposal of solid wastes at a production facility in Hopewell, Virginia. An estimated 10,000-30,000 kg (22,000-66,100 lb) of chlordecone is associated with bottom sediment in the James River estuary (Huggett and Bender 1980 Nichols 1990). This sediment serves as a reservoir for future release of chlordecone via resuspension of sediments resulting from storms or dredging activities (Lunsford et al. 1987). 

Disposal of solid wastes is a significant problem for the petrochemical industry. Waste solids include water treatment sludge, ashes, fly ash and incinerator residue, plastics, ferrous and nonferrous metals, catalysts, organic chemicals, inorganic chemicals, filter cakes, and viscous solids. 

The RCRA controls the disposal of solid waste and requires that all wastes destined for land disposal be evaluated for their potential hazard to the environment. Solid waste includes liquids, solids, and containerized gases and is divided into nonhazardous waste and hazardous waste. The various amendments are aimed at preventing the disposal problems that lead to a need for the Comprehensive Environmental Response Compensation and Liability Act (CERCLA), or Superfund, as it is known. 

Release routes of 3,3 -dichlorobenzidine to the environment appear to be waste waters, sludges, and solid wastes where emissions are not properly controlled during the use of 3,3 -dichlorobenzidine or during its chemical transformation to pigments. The compound has been found in water and soil at hazardous waste sites, a result of the improper land disposal of solid wastes. 

On the basis of chemical profile, Wood (38) predicted that arsenic, selenium, and tellurium will be methylated in the environment, and lead, cadmium, and zinc will not. Elemental concentration in the aquatic food chain has been reported for As (39), Hg (40), Cd (41), Pb (42), and Cu (43). The biological half-life of methylmercury in fish, for example, is one to two years (44). Pillay et al. (40) implicated heavy coal burning in the mercurial contamination of plankton and fish populations of Lake Erie. Other metals, notably cadmium, have been shown to be incorporated into the grazing grasses surrounding a coal burning source (27). Trace element contamination, therefore, can enter the food chain at various points. Disposal of solid wastes in the form of ash and slag is yet another environmental consideration (45). 

Figure 11.6. Thickeners for preconcentration of feed to filters or for disposal of solid wastes [see also the rake classifier of Fig. 12.2(e)]. (a) A thickener for concentrating slurries on a large scale. The rakes rotate slowly and move settled solids towards the discharge port at the center. Performance data are in Table 11.11 Brown, Unit Operations, Wiley, New York, 1950). (b) Deep cone thickener developed for the National Coal Board (UK), in a unit about lOftdia the impellers rotate at about 2rpm and a flow rate of 70 m3/scc with a solids content of 6wt%, concentrates to 25-35 wt % (Svarovsky, 1981).

Two important sources of elemental phosphorus in soil are the creation of slag piles during the production of white phosphorus, and the disposal of solid wastes containing elemental phosphorus in hazardous waste landfills (Berkowitz et al. 1981 Idler et al. 1981). The field use of WP/F and red phosphorus/butyl rubber smoke/obscurant releases elemental phosphorus into soil primarily as unburnt phosphorus in munitions (Berkowitz et al. 1981 ... 

Control of Outputs. The objective is to control risks to people outside from activities within the laboratory or products and services generated by the laboratory. For example, the quality of analytical tests or synthesised products, control of the emissions of gases and liquids and the disposal of solid wastes. 

Waste disposal is a serious problem for many chemical plants. The EPA initiative that has greatly curtailed land disposal has had a great effect on waste disposal. The 1984 Resource Conservation and Recovery Act (RCRA) amendments have also made it more difficult to dispose of solid wastes. In addition, RCRA required all interim status hazardous-waste facilities to meet ground-water monitoring and insurance requirements by late 1985. This included hazardous-waste surface impoundments. Since 1988, a double liner and leachate collection system have also been required. 

At present, there is no vaccine to protect against dengue. The most effective method of prevention is to eliminate the mosquito that causes the disease. This requires removal of the mosquito breeding sites, a process known as source reduction. Proper disposal of solid waste helps to reduce the collection of water in discarded articles. Other control measures include preventing mosquito bites with screens, protective clothing, and insect repellents in epidemic risk areas, application of insecticide is practiced through an application method known as fogging to decrease the mosquito population. 

Probably the strongest conclusion produced by these information gathering activities was that people were generally ambivalent about the refinery, voicing neither major criticisms nor major support. In general, those contacted believed that the refinery complied with environmental laws and that this compliance probably protected the community. Most people felt that there were more pressing problems in the Yorktown area than the refinery. For example, land development, traffic, and sewer and water problems were cited as major quality-of-life concerns. When specifically asked about air pollution, water pollution, and disposal of solid waste, residents indicated that they did have a concern with respect to the oil refinery. These concerns, however, were not strongly felt and not specific. 

Disposal of Solid Wastes from Coal Utilization... 

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