The use of wells for the subsurface disposal of wastes has been practiced in Kansas since 1935. All the early waste-disposal wells were used to dispose of oil-field brine. Permits for the first industrial waste-disposal wells other than oil-field wells were issued in 1952.

Two state agencies have jurisdiction over the subsurface disposal of oil-field wastes in Kansas. Before using a well for the subsurface disposal of oil-field or gas-field brines, the operator must submit plans and specifications for each disposal well to the Kansas State Corporation Commission. These must be approved by both the State Corporation Commission and the Kansas State Department of Health. The Corporation Commission, through its Oil and Gas Conservation Division, determines that the use of the proposed well will not result in loss or waste of gas or petroleum resources. The Department of Health, through its Oil Field and Subsurface Disposal unit, Division of Environmental Health, determines that use of the proposed well will not result in pollution to the water resources of he state.

Before using a well for the subsurface disposal of industrial wastes other than oil-field or gas-field wastes, an application must be filed with, and a permit issued by, the Kansas State Department of Health. The maximum wellhead pressure that may be used to inject wastes into both classes of wells must be approved by the Department of Health. Periodic field checks of the amount of pressure used are made by field personnel of the Department of Health. The Oil Field and Subsurface Disposal unit is staffed by a supervisory geologist in Topeka and by 8 area geologists, each of whom is responsible for a specific section of the state.

At present, there are 3,200 approved oil-field and gas-field saltwater disposal wells in use receiving a total of about 4,000,000 bbl of salt water per day. Not included are 2,600 saltwater repressuring systems in the state, which are made up of from one to several hundred injection wells. The depths of the oil- and gas-field disposal wells range from less than 500 to about 6,000 ft. Thirty-eight zones ranging from Upper Permian to Precambrian are being used. About 60% of the wells inject wastes into limestones or dolomitic rocks, 25% into sandstone, 5% into sandy or gypsiferous shale, 5% into salt or anhydrite zones, and 5% into conglomerate or granite wash. Injection pressures being used range from gravity at the wellhead to 0.5 psi/ft of depth to the injection zone.

There are 31 industrial waste-disposal wells (other than oil- or gas-field wells) at 21 plants in the state including 10 LPG underground storage projects, 2 salt companies, 3 petroleum refineries, 4 natural gas compressor stations, 2 chemical manufacturing plants, and 2 fertilizer plants. Most industrial waste being disposed of in the subsurface consists of salt brine and is disposed of in Arbuckle rocks at depths ranging from about 3,000 to 6,000 ft. All wells are constructed to preclude any hazard to fresh water. The Department of Health's present policy concerning industrial wastes is that only those wastes that cannot be treated and disposed of by other practical methods will be considered for disposal in the subsurface. Use of the most permeable injection zone available at each s te is required regardless of depth in order to eliminate the need for wellhead injection pressure.

Experience with both industrial and oil-field disposal wells shows that most operational problems are caused by (1) selecting an injection zone with inadequate permeability, (2) no preliminary waste treatment or inadequate waste treatment, or (3) failure to provide an effective maintenance program.

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