7 Del. Admin. Code § 7102-58.0

Current through Register Vol. 28, No. 4, October 1, 2024

Section 7102-58.0 - Classification of injection wells

58.1 Injection wells are classified as follows: [note: some of these types of wells are prohibited in Delaware, including all Class II, III, IV, and VI injection wells]

58.2 Class I.

58.2.1 Wells used by generators, owners or operators of hazardous waste management facilities to inject hazardous waste beneath the lowermost aquifer containing, within one-quarter (1/4) mile of the well bore, an underground source of drinking water.

58.2.2 Industrial and domestic disposal wells which inject fluids beneath the lowermost aquifer containing, within one-quarter (1/4) mile radius of the well bore, an underground source of drinking water.

58.3 Class II {prohibited}. Wells which inject fluids:

58.3.1 Which are brought to the surface in connection with natural gas storage or 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.

58.3.2 For enhanced recovery of oil or natural gas.

58.3.3 For storage of hydrocarbons which are liquid at standard temperature and pressure.

58.4 Class III {prohibited}. Wells which inject for extraction of minerals including:

58.4.1 Mining of sulfur by the Frasch process;

58.4.2 In situ production of uranium or other metals. This category includes only in-situ production from ore bodies which have not been conventionally mined. Solution mining of conventional mines such as stopes leaching is included in Class V.

58.4.3 Solution mining of salts or potash.

58.5 Class IV {prohibited}.

58.5.1 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 a formation which contains an underground source of drinking water within one-quarter (1/4) mile of the well.

58.5.2 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 above a formation which contains an underground source of drinking water within one-quarter (1/4) mile of the well.

58.5.3 Wells used by generators of hazardous waste or owners or operators of hazardous waste management facilities to dispose of hazardous waste, which cannot be classified under this Section (e.g., wells used to dispose of hazardous wastes into or above a formation which contains an aquifer which has been exempted pursuant to Section 57.0).

58.6 Class V. Injection wells not included in Class I, II, III, IV or VI. Typically, Class V wells are shallow wells used to place a variety of fluids directly below the land surface. However, if the fluids placed in the ground qualify as a hazardous waste under the Resource Conservation and Recovery Act (RCRA), the well is either a Class I or Class IV well, not a Class V well. Examples of Class V wells include, but are not limited to:

58.6.1 Air conditioning return flow wells used to return to the supply aquifer the water used for heating or cooling in a heat pump.

58.6.2 Cooling water return flow wells used to inject water previously used for cooling, which contain no additives.

58.6.3 Drainage wells used to discharge or inject surface fluid, primarily storm runoff, directly into a USDW.

58.6.4 Recharge wells used to replenish the water in an aquifer.

58.6.5 Salt water intrusion barrier wells used to inject potable water into a fresh water aquifer to prevent the intrusion of salt water into the fresh water.

58.6.6 Sand backfill and other backfill wells used to inject a mixture of water and sand, mill tailings or other solids into mined-out portions of subsurface mines whether what is injected is a radioactive waste or not.

58.6.7 Septic system wells used to inject the waste or effluent from a multiple dwelling, business establishment, or community septic tank. The UIC requirements do not apply to single family residential septic system wells, or to non-residential septic system wells which are used solely for the disposal of sanitary waste and have the capacity to serve fewer than 20 persons a day; see also the State of Delaware Regulations Governing the Design, Installation and Operation of On-Site Wastewater Treatment and Disposal Systems.

58.6.8 Subsidence control wells (not used for the purpose of oil or natural gas production) used to inject fluids into a non-oil or gas producing zone to reduce or eliminate subsidence associated with the overdraft of fresh water.

58.6.9 Injection wells associated with the recovery of geothermal energy for heating, aquaculture and production of electric power.

58.6.10 Experimental injection well technologies.

58.6.11 Aquifer Storage and Recovery (ASR) wells.

58.7 Class VI {prohibited}. Injection wells used to inject Carbon Dioxide (CO₂) for long-term storage, also known as Geologic Sequestration of CO₂.

7 Del. Admin. Code § 7102-58.0

21 DE Reg. 978 (6/1/2018) (Final)