The company is turning produced water into a resource for farmers at a cost to its E&P client that is competitive with hauling and disposal via well reinjection.
On September 29, Encore Green Environmental (EGE) began discharging treated produced water to land in Laramie County, Wyoming. The first batch of 360 bbls was applied to a 15-acre area, and the company expects that volume to rise to 1,900 bbls by the end of October. Issued by the Wyoming Department of Environmental Quality (WDEQ) in January 2020, EGE’s permit allows for a total of 7,000 bbls of treated produced water to be discharged by this coming December.
Though the state already grants land discharge permits for streams such as treated municipal water and some agricultural wastewater, EGE’s is the first permit concerning the application of oil & gas produced water for crop irrigation. WDEQ public information officer Keith Guille told WiO that the department initially faced some challenges in evaluating the project and establishing a permit, mainly due to difficulties in identifying all potential organic pollutants and appropriate limits to prevent adverse impacts to crops, soil, surface water and groundwater.
“What we defaulted to was the presumption that the limits needed to be equivalent to those that we applied to drinking water,” Guille said.
EGE evaluated several different technologies considering both the raw produced water quality and the stipulations of its discharge permit (see table below). The company configured a treatment system comprising low-micron prefiltration and carbon filtration to remove residual oil and grease ahead of a seawater reverse osmosis unit.
“There was some biological activity in the produced water because it was stored in aboveground containment. We didn’t want a membrane package that was very susceptible to biofouling, so we went with a seawater system,” Darren Smith, EGE director of water technology, told WiO. He added that the system was able to realize more than 70% efficiency.
In addition to directly reporting to the WDEQ, EGE publishes project information – including lab analysis of water and soil samples – on its Ag Water Solutions website. The data is publicly available and protected via blockchain encryption to ensure data integrity.
So far, most parameters have come back as nondetectable, indicating that EGE’s system is working well. Smith believes that the WDEQ will eventually remove requirements for parameters that continue to be nondetectable in lab analysis, something which would speed up testing and save on costs, in addition to possibly simplifying the permitting process for similar projects in the future.
Since granting EGE’s permit, the WDEQ has developed three countywide permits that would allow any company to apply treated produced water to land. However, the agency has not yet received any new applications from other companies.
“If all standards and protections are met to ensure that the environment is not adversely affected, this activity could be very beneficial for arid states like Wyoming,” Guille said.
The EGE team agrees. The company is already pursuing additional projects not only Wyoming, but also in New Mexico and Texas – both states that are facing deepening water stress and concomitant challenges of rising produced water volumes and disposal constraints – as well as Illinois. In the Texas Permian Basin, EGE has already partnered with landowners to create an irrigation district.
Landowner buy-in something which Smith believes is critical to the realization of future beneficial reuse projects.
“I think we’re going to be able to really sense some success when operators present this option to landowners to manage water,” he said. “Operators are guests on landowners’ property and [beneficial reuse of produced water] is the most responsible thing to do. That would be a real signal that there’s commitment from everybody to do the right thing.
PERMIT REQUIREMENTS AND BATCH 01 TREATMENT RESULTS FOR SELECTED WATER QUALITY PARAMETERS
|Parameter||Permit requirement||Treatment result|
|Ammonia||30 mg/l||1.4 mg/l|
|Chloride||100 mg/l||8 mg/l|
|Hydrogen sulfide||4.20 ug/l||0.11 ug/l|
|Oil & grease||10 mg/l||0|
|TDS||480 mg/l||19 mg/l|
Source: Ag Water Solutions