§11-23-06 - Classification of injection wells.

§11-23-06 Classification of injection wells.

(a) The department shall classify existing and proposed injection wells in accordance with the five classes of wells described in this section. Wells in classes I through IV are prohibited and are defined as follows:

(1) Class I. Wells which inject fluids beneath the lowermost formation containing, within one quarter mile of the well bore, an underground source of drinking water and which are used by:

(A) Generators of hazardous waste or owners or operators of hazardous waste management facilities; and

(B) Disposers of industrial and municipal waste fluids.

(2) Class II. Wells which inject fluids:

(A) Which are brought to the surface in connection with conventional oil or natural gas production and may be commingled with waste waters from gas plants which are an integral part of production operations, unless those waters are classified as a hazardous waste at the time of injection;

(B) For enhanced recovery of oil or natural gas; and

(C) For storage of hydrocarbons which are liquid at standard temperature and pressure.

(3) Class III. Wells which inject for extraction of minerals including:

(A) Mining of sulfur by the Frasch process;

(B) In-situ production of uranium or other metals, using unconventional techniques to mine ore bodies; and

(C) Solution mining of salts or potash.

(4) Class IV. Wells used by generators of hazardous waste or of radioactive waste, by owners or operators of hazardous waste management facilities, or by owners or operators of radioactive waste disposal sites to dispose of hazardous waste or radioactive waste into any geohydrologic formation or a formation, which, within one-quarter of a mile of the well, contains an underground source of drinking water (USDW), even if exempted.

(b) Without exception, only class V wells shall be permissible and are defined as follows:

(1) Subclass A. Injection wells which inject fluids into an underground source of drinking water. Subclass A wells include:

(A) Sewage injection wells; and

(B) Industrial disposal wells other than those classified under subclasses AB or B.

(2) Subclass AB. Injection wells which inject only into exempted aquifers. Subclass AB wells include:

(A) Sewage injection wells; and

(B) Industrial disposal wells, other than those classified under subclass B, such as brine disposal wells used in a desalinization process.

(3) Subclass B. Injection wells which inject non-polluting fluids into any geohydrologic formation, including underground sources of drinking water. Subclass B wells include:

(A) Air conditioning return flow wells used to return the water used for heating or cooling in a heat pump;

(B) Cooling water return flow wells used to inject water previously used for cooling;

(C) Recharge wells used to replenish, augment, or store water in an aquifer;

(D) Salt water intrusion barrier wells, used to prevent the intrusion of salt water into fresh water, if they inject water of equal or lesser chloride concentration as that portion of the aquifer into which injected;

(E) Wells used in aquaculture, if the water in the receiving formation has, either:

(i) An equal or greater chloride concentration as that of the injected fluid; or

(ii) A total dissolved solids concentration in excess of five thousand mg/L.

(F) Injection wells used in an experimental technology, which is one that has not been proven feasible under the conditions in which it is being tested; and

(G) All wells not included in subclasses A, AB, C, D, or E of class V or in classes I through IV.

(4) Subclass C. Injection wells which inject surface fluids, i.e., storm runoff, into any geohydrologic formation.

(5) Subclass D. Injection wells which inject overflows, or relief flows, from potable water systems into any geohydrologic formation.

(6) Subclass E.

(A) Injection wells associated with the development and recovery of geothermal energy, provided that the geothermal effluent will be injected at a depth that will not be detrimental to underground sources of drinking water. If injection is to occur below the basal water table, the receiving formation water shall be tested and injection allowed if the receiving water has, either:

(i) An equal or greater chloride concentration as that of the injected fluid; or

(ii) A total dissolved solids concentration in excess of five thousand mg/1; or

(iii) An equivalent or lesser water quality than the injected fluid.

(B) Subclass E injection wells include:

(i) Brine injection wells for the disposal of excess water from the steam-flashing process;

(ii) Condensate injection wells for the disposal of condensate from electric generators; and

(iii) Gas injection wells for the disposal of non-condensible gases entrained in an aqueous solution.

         [Eff. 7/6/84; am and comp NOV 12 1992(Auth: HRS S340E-2) (Imp: HRS §340E-2, 40 CFR §§144.6 and 146.5)

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