TYPES OF WASTE AND ITS SOURCES OF GENERATION

1.    Inorganic wastes

Acid and Alkalis – are among the major components of the total amount of hazardous waste generated. Acid wastes come mainly from the surface preparation and finishing of metals. The major hazard with acid and alkalis is their corrosive action, though the presence of toxic constituents.

Cyanide wastes – generated primarily in the metal finishing industry and in the heat treatment of steel. The principal hazard associated with cyanide waste is their acute toxicity.

Heavy Metals Sludges and Solutions – those containing the toxic metals, arsenic, cadmium, lead, mercury, nickel, zinc and copper. These wastes are generated from a wide range of manufacturing processes, including chlorine production, pigment production, wood preserving, battery production, textiles, metal plating and tanning.

Asbestos wastes – normally arises from lagging wastes, power stations, industrial plants, gas works, dockyards, hospitals and educational establishments. Waste from the demolition or rebuilding of locomotives and railways carriages, from building and demolition sites may also consider as materials containing asbestos.

Other solid residues – generated from the smelting and refining of metals. Dusts and sludges generated from these processes typically contain toxic metals include waste lubrication and hydraulic fluids, bottom sludges from oil storage tanks, waste cutting oils and interceptor waste.

2.    Oily wastes – are generated primarily from the processing use in storage of mineral oils. Example include waste lubrication and hydraulic fluids, bottom sludges from oil strogae tanks, waste cutting oils and interceptor waste.

3.    Organic Wastes

Halogenated solvent wastes – are generated primarily from dry cleaning operations, metal cleaning in the engineering industry, and to a much smaller extent from decreasing and delaying processes in the textile and leather industries.

Non-halogenated solvent wastes – include a large number of hydrocarbons, and oxygenated carbons, of which the most commonly used are white spirit, toluence, methanol, isopropanol and ethanol.

PCB wastes – are generated from the manufacture of PCB and from the decommissioning of equipment in which PCB’s are used, principally as dielectric fluid in transformers and capacitors and also as hydraulic fluids and heat transfer fluids.

Paints and Resin wastes – are generated from a variety of formulation and other tertiary chemical processes and also in the application of paints and resin to finish products.

Biocide wastes – are generated both the manufacture and formulation of biocides and in the use of these compounds in agriculture, horticulture and a variety of other industries.

Organic chemical residues – are also generated from coal carbonization and by-product operations and from the manufacture or primary, secondary and tertiary chemical products. These wastes streams include both halogenated and non-halogenated chemicals.

4.    Putrescible organic wastes – include wastes from the production of edible oils, as well as leftover from slaughter houses, tanneries, and other animal-based products.

5.    High volume/low hazard wastes – include those wastes which present relatively low hazards, but may pose problems because of their high volumes. Examples are: drilling muds, from petroleum and gas extraction, and fly ash from fossil fuel-fired power plants, mine tailings or metaliferous slags.

Treatment prior to the land disposal of hazardous and toxic wastes can be accomplished by:

1.    Detoxification of the wastes

2.    Separation and concentration of the hazardous constituents in a reduced volume

3.    Stabilization and solidification of the waste to inhibit leaching.