Pennsylvania Oil and Gas Waste Mapping Tool: Glossary and Sources

General Information

The Pennsylvania Oil and Gas Waste Mapping Tool was created by PSE Healthy Energy with funding from the Heinz Endowments. The project’s goal is to examine liquid and solid waste from conventional and unconventional oil and gas operations in Pennsylvania across time and space.

The Pennsylvania Oil and Gas Waste Mapping Tool includes waste generation by county and waste handling locations across Pennsylvania and neighboring states.

This page provides definitions and descriptions of the data used in the Pennsylvania Oil and Gas Waste Mapping Tool as well as specific information about the data sources used. For additional questions please email

Definitions and Descriptions of Data

general terms

  • Conventional well: A conventional gas well, also known as a traditional well, is a well that produces oil or gas from a conventional formation. Conventional formations are variable in age, occurring both above and below the Elk Sandstone. While a limited number of such gas wells are capable of producing sufficient quantities of gas without stimulation by hydraulic fracturing, most conventional wells require this stimulation technique due to the reservoir characteristics in Pennsylvania. Stimulation of conventional wells, however, generally does not require the volume of fluids typically required for unconventional wells (PADEP, 2012).
  • Unconventional well: A well that is drilled into an unconventional formation, which is defined as a geologic shale formation below the base of the Elk Sandstone or its geologic equivalent where natural gas generally cannot be produced except by horizontal or vertical well bores stimulated by hydraulic fracturing” (PADEP, 2012).


  • barrel: Unit of volume for wastewater.  One barrel equals 42 US gallons, or approximately 159 liters.
  • ton: Unit of weight for solid waste.  One ton equals 2,000 pounds.

Waste handling methods

  • Centralized waste treatment facilities: Any facility that treats (for disposal, recycling or recovery of material) any hazardous or non-hazardous industrial wastes, hazardous or non-hazardous industrial wastewater, and/or used material received from off-site. “CTW facility” includes both a facility that treats waste received exclusively from off-site and a facility that treats wastes generated on-site as well as waste received from off-site. For example, an organic chemical manufacturing plant may, in certain circumstances, be a CWT facility if it treats industrial wastes received from offsite as well as industrial waste generated at the organic chemical manufacturing plant. CWT facilities may also include re-refiners and may be owned by the federal government (40 CFR 437.2).
  • Injection disposal well: A well used to place fluid underground into porous geologic formations. These underground formations may range from deep sandstone or limestone, to a shallow soil layer. Injected fluids may include water, wastewater, brine (salt water), or water mixed with chemicals (EPA Underground Injection Control (UIC)).
  • Landfill: (i) Municipal waste landfill – A facility using land for disposing of municipal waste. The facility includes land affected during the lifetime of operations including, but not limited to, areas where disposal or processing activities actually occur, support facilities, borrow areas, offices, equipment sheds, air and water pollution control and treatment systems, access roads, associated onsite and contiguous collection, transportation and storage facilities, closure and postclosure care and maintenance activities and other activities in which the natural land surface has been disturbed as a result of or incidental to operation of the facility. The term does not include a construction/demolition waste landfill or a facility for the land application of sewage sludge. (ii) Residual waste landfill – A facility for disposing of residual waste. The term does not include a residual waste disposal impoundment or a facility for the land application of residual waste. The term also does not include a facility at which municipal waste, other than industrial lunchroom or office waste generated by the operator, construction/demolition waste generated by the operator, or certain special handling waste is disposed (025 Pa. Code § 287.1.).
  • NPDES: National Pollutant Discharge Elimination System, regulatory permitting for points sources that discharge pollutants to surface waters (EPA, 2019).
  • Publicly owned treatment works: (i) A treatment works which is owned by a state or municipality; (ii) The term includes any devices and systems used in the storage, treatment, recycling and reclamation of municipal sewage or industrial wastes of a liquid nature; (iii) The term also includes sewers, pipes or other conveyances if they convey wastewater to a POTW treatment plant; (iv) The term also means the municipality as defined in section 502(4) of the Federal Act (33 U.S.C.A. § 1362(4)), which has jurisdiction over the indirect discharges to and the discharges from such a treatment works (25 Pa. Code § 92a.2.).
  • Residual waste facilities:  A facility for disposing or processing of residual waste. Includes residual waste disposal or processing facilities listed with our without a general permit. Residual waste – Garbage, refuse, other discarded material or other waste, including solid, liquid, semisolid or contained gaseous materials resulting from industrial, mining and agricultural operations and sludge from an industrial, mining or agricultural water supply treatment facility, wastewater treatment facility or air pollution control facility, if it is not hazardous. The term does not include coal refuse as defined in the Coal Refuse Disposal Control Act. The term does not include treatment sludges from coal mine drainage treatment plants, disposal of which is being carried on under and in compliance with a valid permit issued under the Clean Streams Law (025 Pa. Code § 287.1.).
  • Reuse: A material that meets one of the following conditions: (i) The material is employed as an ingredient, including use as an intermediate, in an industrial process to make a product. A material will not satisfy this condition if distinct components of the material are recovered as separate end products, as when metals are recovered from metal-containing secondary materials. (ii) That material is employed in a particular function or application as an effective substitute for a commercial product (025 Pa. Code § 287.1.).
  • Road spreading: Application of brine produced from oil and gas wells and other sources such as brine treatment plants and brine wells on unpaved secondary road systems for beneficial use as a dust suppressant and road stabilizer (PADEP, 2011).
  • Surface impoundment: A facility or part of a facility which is a natural topographic depression, manmade excavation, or diked area formed primarily of earthen materials although it may be lined with synthetic materials, and which is designed to hold an accumulation of liquid wastes or wastes containing free liquids. The term includes holding, storage, settling and aeration pits, ponds and lagoons. The term does not include injection wells (025 Pa. Code § 287.1.).

Data Sources

Data: Pennsylvania Oil and Gas Production / Waste Reports.
Source: Pennsylvania Department of Environmental Protection (PADEP). 2018.
Available at:
Most recent download: April 25, 2018
Data years: 1991 – 2017

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