Mining waste is generated in three primary ways. First, in most mining operations, large amounts of rock and soil need to be removed to get to the valuable ore. This waste material is generally left on the surface at the mine site. Second, milling operations use various technologies to extract the valuable material from the ore. These techniques vary from relatively simple grinding and sorting to sophisticated chemical separation processes. Regardless of the technique involved, once the valuable material is recovered, the remaining waste material, commonly known as tailings, must be disposed of. Solid materials are typically dumped on the land near the milling site, and liquid wastes are typically stored in ponds. It is difficult to get vegetation to grow on these piles of waste rock and tailings, so they are unsightly and remain exposed to rain and wind. Finally, the water that drains or is pumped from mines or that flows from piles of waste rock or tailings often contains hazardous materials (such as asbestos, arsenic, lead, and radioactive materials) or high amounts of acid that must be contained or treated - but often are not. Many types of mining operations require vast quantities of water for the extraction process. The quality of this water is degraded, so it is unsuitable for drinking, irrigation, or recreation. Since mining disturbs the natural vegetation in an area, water may carry soil particles into streams and cause erosion and siltation. Some mining operations, such as strip mining, rearrange the top layers of the soil, which lessens or eliminates its productivity for a long time. Agricultural waste is the second most common form of waste and includes waste from the raising of animals and the harvesting and processing of crops and trees. Other wastes associated with agriculture, such as waste from processing operations (peelings, seeds, straw, stems, sludge, and similar materials). Since most agricultural waste is organic, it is used as fertilizer or for other soilenhancement activities. Other materials are burned as a source of energy, so little of this waste needs to be placed in landfills. However, when too much waste is produced in one place, there may not be enough farmland available to accept the agricultural waste without causing water pollution problems associated with runoff or groundwater contamination due to infiltration. Industrial solid waste from sources other than mining includes a wide variety of materials such as demolition waste, foundry sand, scraps from manufacturing processes, sludge, ash from combustion, and other similar materials. These materials are tested to determine if they are hazardous. If they are classified as hazardous waste, their disposal requires that they be placed in special hazardous waste landfills. Municipal solid waste (MSW) consist of all the materials that people in a region no longer want because they are broken, spoiled, or have no further use. It
includes waste from households, commercial establishments, institutions, and some industrial sources. Specialists and local communities, in addition to governmental agencies and local authorities generally decide how waste will be managed whether by landfill, incineration, recycling, composting, waste reduction, or a combination. Bio-waste [18], [25] is defined as biodegradable garden and park waste, food and kitchen waste from households, restaurants, caterers and retail premises, and comparable waste from food processing plants. It does not include forestry or agricultural residues, manure, sewage sludge, or other biodegradable waste such as natural textiles, paper or processed wood, that are biomass categories, as well. It also excludes those byproducts of food production that never become waste. The total annual arising of bio-waste in the EU is estimated at 76.5-102 Mt food and garden waste included in mixed municipal solid waste and up to 37 Mt from the food and drink industry. Bio-waste is a putrescible, generally wet waste. There are two major streams (i) green waste from parks, gardens etc. and (ii) kitchen waste. The former includes usually 50-60 % water and more wood (lignocelluloses); the latter contains no wood, but up to 80 %, by mass, water. Waste management options for bio-waste include, in addition to prevention at source, collection (separately or with mixed waste), anaerobic digestion and composting, incineration, and environmental friendly land filling. The environmental and economic benefits of different treatment methods depend significantly on local conditions such as population density, infrastructure and climate as well as on markets for associated products (energy and composts). Today, very different national policies apply to bio-waste management, ranging from little action in some Member States to ambitious policies in others. Hazardous waste means waste that requires special precaution in its storage, collection, transportation, treatment or disposal to prevent damage to persons or property, and includes explosive, flammable, volatile, radioactive, toxic and pathological wastes. This category includes the management of three types of hazardous wastes from their source to ultimate disposal: (i) the radioactive materials, which are primarily the responsibility of specials national and international authorities, (ii) medical wastes, and (iii) the nonradioactive liquid industrial wastes, which are mainly under state or provincial jurisdiction. Hazards in the environment may arise also from natural occurrences like floods and hurricanes, from human environmental disturbances like CO2 build-up and acid rain, and from the improper treatment and disposal of the toxic and hazardous wastes generated by an industrialized society [1], [2].