As discussed in an earlier post about the management of oil field wastes, most exploration and production waste is not regulated as a hazardous waste. Instead, it is regulated as a solid waste. Even so, as discussed in a recent article by Stephen Ellis:

“One of the biggest problems in the oil and gas industry today is water management. Solving the technical and economic challenges around managing the millions of gallons of water used to properly fracture tight oil and gas wells has been called the holy grail of the industry by Southwestern Energy CEO Steve Mueller. He estimates that water transportation (primarily trucking) costs around $1.5 million (25%) of the $6 million that an average Marcellus well costs.”

See: Stephen Ellis, “Oilfield Water Management: The Oil And Gas Industry’s Holy Grail,” Seeking Alpha, March 31, 2013.

Water Used in Operations

Water is used in the drilling of the well. It is also used in the stimulation — i.e., fracking — of the well. According to the Ohio Department of Natural Resources (ODNR), most of the water used in fracturing remains thousands of feet underground in the formation. However, about 15-20 percent returns to the surface through a steel-cased well bore and is temporarily stored in steel tanks or lined pits. The wastewater that returns to the surface after hydraulic fracturing is called flowback. Later, as the well is producing hydrocarbons, it also produces water named, appropriately enough, “produced water.”

All water that flows out of a well needs to be treated, recycled or disposed of properly. Perhaps the most common and least expensive way to deal with this wastewater is to pump it back underground through a specialized well commonly referred to as either an “injection well” or “disposal well.” There are only a handful of disposal wells in Pennsylvania but there are almost 200 in Ohio.

The abundance of disposal wells in Ohio makes it a popular destination for flowback and produced water disposal from surrounding states.

Regulatory Response 

The history of how disposal wells came to replace evaporation pits for the safe disposal of certain kinds of drilling fluids is described in a 2011 ODNR-DOGRM presentation to the Ohio Geological Society. Injection wells are now heavily regulated to ensure the safety of people and the environment.

To address the possibility of groundwater contamination by injection wells, the regulation of multiple types of injection wells, including those for the disposal of flowback and produced wastewater, is authorized in the Safe Drinking Water Act, 42 U.S.C. § 300f, and its implementing regulations, 40 CFR Parts 144, 145 and 146. Under the Safe Drinking Water Act, Ohio received delegation from USEPA to implement and enforce its the regulatory program for injection wells in 1983. Section 1509.22 of the Ohio Revised Code also regulates the storage and disposal of brine, and in 2010 and 2012, the Ohio General Assembly further tightened the standards applicable to these wastewater streams in response to the shale play.

Permits are required to drill a disposal well. (R.C. 1509.221.) Any person who transports brine has to register with the state and get an ID number. Well owners can only use the services of registered persons for wastewater management and those persons are required to file annual reports. (R.C. 1509.223.) Transporters are also required to have insurance in specified amounts and a surety bond. (R.C. 1509.225.) The ODNR regulations are found at OAC 1509:9-3 et seq.

Liquids Eligible for Disposal

The liquids that can be injected into a Class II well include liquids associated with drilling and stimulation activities such as:

  • Pits water, or fluids from drilling and cementing operations
  • Mixture of drilling mud, freshwater and formation brines
  • Flowback or frack water, which is a mixture of chemicals, brine and brackish water associated with horizontal drilling
  • Produced water; i.e., natural formation brine, which is a byproduct of oil and gas production. Brine contains mainly sodium, chloride, calcium, barium, iron, strontium, magnesium, and potassium. Chloride is the predominant constituent with concentrations as high as 200,000 ppm (mg/L).

Approximately 98 percent of oilfield fluids in Ohio are disposed of through injection in disposal wells. The remaining 2 percent is spread legally for dust and ice control. In 2011, more than half of the liquids disposed of in Ohio’s disposal wells came from out of state. (Read more in the ODNR-DOGRM presentation referenced above.)

Since the Underground Injection Control (UIC) program’s inception in 1983, more than 202 million barrels of oilfield fluids have been successfully disposed of, with no reports of ground water contamination incidents. In addition, before the Youngstown event, discussed below, no seismic event had been previously linked to operations at any of the state’s Class II wells. See: “Preliminary Report on the Northstar I Class II Injection Well and The Seismic Events in the Youngstown, Ohio, Area,” ODNR, March 2012.

Permitting Class II Wells

Ohio’s stringent regulations are reflected in the Class II well permitting process. Depending on the projected disposal volume, ODNR establishes a preliminary area of review around the proposed well site of either 1⁄4 mile or 1⁄2 mile, followed by a “pre-site field review.”

A “pre-site field review” involves an inspection by ODNR of the area around the location of a proposed Class II well. The review is intended to identify all water wells, dwellings and surface bodies of water within the area of review. If these types of features are identified in close proximity to the proposed injection well, ODNR has the regulatory discretion to impose additional requirements on the applicant. Likewise, ODNR has the discretion to order seismic testing and monitoring if it believes those are necessary or warranted based on its review of the area.

After an injection well application is reviewed and deemed complete, ODNR also sends instructions for public notice to the well operator. Notice of the proposed permit is then published in the local newspaper by the operator. If there are relevant objections relating to public health or safety, or good conservation practices, ODNR may require a public hearing.

Injection Pressure

The surface injection pressure is initially set by a formula prescribed in OAC 1501:9-3-07 (D) taking into account the specific gravity of the injectate. Thereafter, the well operator reports the specific gravity of the injectate to ODNR on a quarterly basis. If necessary, ODNR can adjust the permitted pressure to ensure that the water is being safely assimilated into the geologic formation.

Mechanical integrity of the well is determined before injection. Thereafter, the regulations require continuous monitoring or monthly mini-tests. Production casing need be at least 300 feet above the injection zone and tubing and packer are required.

On the surface, the injection well facility must be within a dike area with a 30 mil liner or a concrete dike. The truck unloading pad must be concrete with a drain, vault and sump.

ODNR conducts unannounced inspections on each well every 11 to 12 weeks. The inspections include a check of injection and annulus pressures to insure integrity. There is also an overall inspection of the facility and pipelines for leaks.


In the first quarter of 2011, a series of small-magnitude earthquakes occurred in the Youngstown area. After a thorough investigation, ODNR concluded that they had been induced by a nearby injection well — the result of a confluence of extremely rare circumstances. In fact, all evidence indicates that properly located Class II injection wells will not cause earthquakes. See: “Preliminary Report on the Northstar I Class II Injection Well and The Seismic Events in the Youngstown, Ohio, Area,” ODNR, March 2012.

As a result of the Youngstown incident, Ohio adopted new procedures to ensure the set of circumstances that led to seismic activity is not repeated. This comprehensive list of new standards prohibits the drilling of any new wells in the Precambrian basement rock formation and requires thorough reviews and analysis of geologic data as well as ongoing evaluation, monitoring and testing. Read the complete list of standards adopted in March 2012.


Brine and other liquid wastes are an unavoidable by-product of oil and gas production. To the extent they cannot be recycled, underground injection — with appropriate safeguards — is currently one of the most reliable and safe disposal methods available.