Environmental groups filed a legal challenge Friday against a water pollution permit issued to Valley Proteins, an Eastern Shore poultry rendering facility that has long attracted scrutiny for pollution troubles.

They argue the permit, issued by the Maryland Department of the Environment in January, doesn’t include enough protections for the Transquaking River near the facility and relied on insufficient data about the waterway.

The suit, filed in Dorchester County Circuit Court, asks a judge to remand the permit back to MDE for reconsideration. The petitioners are the Chesapeake Bay Foundation, ShoreRivers, Dorchester Citizens for Planned Growth, Friends of the Nanticoke River and the Wicomico Environmental Trust.

“The amount of pollution that MDE permits Valley Proteins to release into Dorchester County waterways will continue the long-term, well-documented harm this facility is causing in the Transquaking River watershed,” said Alan Girard, the Bay Foundation’s Eastern Shore director, in a statement. “The agency that issued the permit under the previous Governor’s administration must be held accountable for not meeting its obligation to protect water quality as required by federal law.”

The groups also expressed concern that the permit, which took effect Feb. 1, will allow Valley Proteins to increase the amount of wastewater it discharges into a tributary of the Transquaking from 150,000 gallons per day to 575,000 gallons per day, although it must adhere to stricter pollution limits if it does so. The facility, located in Linkwood, near Cambridge, boils down poultry byproducts for use in pet food.

“The proposed four-fold increase in wastewater discharge volume will only result in the death of the river unless the current treatment technology is brought to a much higher standard,” said Fred Pomeroy, president of the board of directors for Dorchester Citizens for Planned Growth, which has been advocating for greater pollution controls on Valley Proteins since 2014.

Last year, Valley Proteins agreed to pay hundreds of thousands of dollars in penalties to settle lawsuits over its pollution history. About half a million dollars went to the state as a penalty, and $135,000 went to a fund managed by several of the environmental nonprofits. Darling Ingre- dients, which purchased the Valley Proteins plant in May, is also on the hook for water testing and inspection costs and attorney’s fees.

The Transquaking River, which empties into the Chesapeake Bay through Fishing Bay, is an impaired waterway with recommended pollution limits for nitrogen and phosphorous issued by the Environmental Protection Agency in 2000. At that time, the Valley Proteins plant was the only industrial facility discharging treated wastewater into the river, and it was estimated to be contributing 40% of the river’s nitrogen and 4% of its phosphorous.

“Even with a Total Maximum Daily Load, or ‘pollution diet’ for the river issued in 2000, the Transquaking continues to show signs of degrading water quality with harmful algal blooms, high bacteria levels, and an overabundance of nutrients,” said Matt Pluta, director of riverkeeper programs at ShoreRivers. “Valley Proteins has spent years violating pollution controls, failing to modernize their wastewater treatment plant, and discharging unauthorized waste materials, and now is the time to chart a better path forward.”

In a news release jointly issued Tuesday about their new lawsuit, the environmental groups took issue with the fact that the Maryland Department of the Environment used the Chicamacomico River, rather than the Transquaking River, to help estimate the influx of water that the river could take from Valley Proteins.

“Unlike the Chicamacomico, the Transquaking has an impoundment that impedes its flow and creates Higgins Mill Pond. The Valley Proteins outfall is above the pond where effluent from the plant can linger an average of nine days,” the news release read. “This creates conditions that fuel harmful algal blooms, low oxygen dead zones, and wildlife impacts, especially in hot weather.”

In a response to public comments during the permit process, MDE said there was no U.S. Geological Survey station above the Mill Pond, and a station on the Chicamacomico was the best substitute. The river data was only used to model the free-flowing portion of the Transquaking above the impoundment.

MDE did not respond to a request to comment Tuesday.

In response to concerns about the final permit, shared before the lawsuit’s filing, MDE spokesperson Jay Apperson previously said the permit “includes conditions that will reduce pollution and improve water quality,” adding that the agency hopes the permit will “work in tandem” with September’s settlement to better the facility.

Apperson noted that changes were made to the permit following public comment, including the inclusion of additional temperature monitoring and requiring adequate staffing for the upgraded facility. The permit also includes “substantial reductions” in pollution limits compared with the old one, he added.

Reached for comment, Darling Ingredients repeated a statement the company issued previously in response to concerns about the permit saying it is “committed to continuing to work closely with the Maryland Department of Environment to ensure the Linkwood facility is in full compliance with all relevant rules and regulations.”