Waste disposal and landfill: Control and protection
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dump itself. Although some of these operations are officially sanctioned, most are unofficial. They represent an important function as an informal recycling system contributing to reduction of waste to landfill. Direct exposure to waste materials may, however, present a health hazard. A waste reduction strategy successfully used in a number of countries has been the imposition of a deposit fee refunded upon return of, for example, bottles, cans, tins, paper and other items. Taxes specifically on packaging materials have been implemented in Germany, for example, to reduce unnecessary waste volume. Household composting can be promoted for further waste reduction by subsidized sale of home composting bins. Waste reduction strategies may also include landfill taxes. These provide an economic incentive and generate revenue. The downside to consider in planning policy is that they may also promote illegal (uncontrolled) disposal practices. For instance, imposition of a charge for acceptance of construction and demolition waste at one landfill in Ireland led to a rapid drop in the quantity of such waste delivered to the landfill. Waste incineration can be an effective strategy to substantially reduce the amount of waste that is landfilled. Adequately engineered systems can effectively control air pollution and toxic residues, including those from flue gas cleaning systems, can be encapsulated for safe disposal. A major drawback of this strategy is its high costs, which tend to distract from investments into other options such as recycling. Industrial wastes are often more hazardous than municipal solid waste (MSW). Unregulated disposal, often on site, was commonplace in the past and remains a problem in some regions. Major contamination of groundwater resources can be avoided through specifically designed and managed disposal of wastes from such industries as smelting, electroplating and tanning industries. A case study showing planning steps taken to remedy unregulated disposal of industrial wastes is described in Box 24.1. Box 24.1. Planning priorities for the remediation of contaminated groundwater in the metallurgical centre of Ust-Kamenogorsk, Kazakhstan Metallurgical plants produce fluid and solid waste that is hazardous due to high (toxic) metal concentrations. Disposal of this waste without pretreatment and in locations with limited capacity to attenuate these metal contaminants can lead to groundwater pollution. Ust-Kamenogorsk is a city in northeastern Kazakhstan with a population of 290 000 that was a centre for metallurgy and heavy industry in the former USSR. As a result of uncontrolled dumping of industrial wastes over more than 50 years, 300 000 tons of toxic arsenic mud, 6000 tons of PCBcontaminated mud and 19 million tons of slag, clinker and sludge from metallurgical processes containing mobile metal compounds were stored on permeable ground. Another eight million tons of fly ash from coal-fired heat and power plants, containing fluoride and boron have been deposited within the city area. The alluvial aquifer underlying the city is the sole water resource for the city water supply but was heavily polluted by arsenic, boron, fluoride, cadmium, copper, lead, manganese, selenium and zinc. High chloride, nitrate and sulphate contents are encountered in the contamination plumes. Contamination plumes in the groundwater clearly relate to dumps of metallurgical sludges and to seepage of process water from leaking pipe work and cracked factory floors (von Hoyer and Muff, 2001).