Under current EPA effluent guidelines, treated produced water cannot be discharged into surface waters in the US except for…
Under current EPA effluent guidelines, treated produced water cannot be discharged into surface waters in the US except for instances west of the 98th meridian under Subpart E (see below). That forces most producers to turn to injection, third-party treaters, or reuse in production. In May of this year, the EPA initiated a study that may change this. Given the water balance and the ballooning volume of produced water, the EPA is exploring potential federal regulations that may allow for broader discharge of treated produced water to surface waters. Presently, the only treated discharge allowed is governed by CFR 40 435 Subpart E (see below).
The EPA has started a dialogue with stakeholders, a dialogue that begins with questions. Are there technologies that would make this economically viable? Are there state laws and regs that impede discharge or beneficial reuse? What are the costs? Is operating data available on systems achieving dischargeable standards? Do federal regulations need to be altered to make this happen? What should the dischargeable standards be?
Why is the EPA asking all these questions? They have been prompted by states, particularly those in arid regions, to look into beneficial reuse. So far only one of those states, New Mexico, has stepped up and signed an memorandum of understanding of cooperation with the EPA.
After the dialogue stage, EPA will invite interested parties to Washington DC. Then they’ll produce a white paper that will go up the chain of command for action, if any is merited. They encourage water technology providers and E&P companies to share advancements that apply to produced water discharge.
Subpart E
Subpart E applies to onshore facilities located in the continental U.S. and west of the 98th meridian for which the produced water has a use in agriculture or wildlife propagation when discharged into navigable waters. Definitions in 40 CFR 435.51(c) explain that the term ‘‘use in agricultural or wildlife propagation’’ means that (1) the produced water is of good enough quality to be used for wildlife or livestock watering or other agricultural uses; and (2) the produced water is actually put to such use during periods of discharge. The regulations at 40 CFR 435.52 specify that the only allowable discharge is produced water, with an oil and grease concentration not exceeding 35 milligrams per liter (mg/L). The BPT regulations prohibit the discharge of waste pollutants into navigable waters from any source (other than produced water) associated with production, field exploration, drilling, well completion, or well treatment (i.e., drilling muds, drill cuttings, produced sands).