Waste Management of New Mexico Inc. has denied wrongdoing in its landfill disposal of material from a brackish groundwater well site in 2018.

In October, the New Mexico Environment Department issued a notice of violation saying Waste Management’s didn’t properly document and test 288 tons of solids left from evaporation of water produced during water-treatment testing at the well site. The material was disposed of at the Rio Rancho landfill in 2018.

NMED spokeswoman Maddy Hayden has said the landfill generally complies with regulations and the department has no concerns about its ability to isolate waste from the environment. The issue was with the classification, testing and obedience to regulations for the waste, which NMED considers sludge and special waste.

The Waste Management response, signed by District Manager Doug Shimic and dated Nov. 6, said NMED hadn’t provided proof of wrongdoing and asked that the notice of violation be retracted. The response also requested that NMED issue a statement that the Rio Rancho landfill protects human health and the environment.

Shimic wrote that of the loads in question, a customer classified 48 as clean dirt and seven as yard, construction or demolition waste. Waste Management hasn’t received clear evidence that those loads came from any entity associated with the well site, he wrote.

The customer didn’t indicate that the loads were special waste or sludge, Shimic wrote. He added that landfill employees inspected the loads and didn’t see or smell anything conflicting with the customer’s classification.

Shimic also questioned whether the waste was sludge, since the definition refers to water and wastewater plants and doesn’t include cleaned wastewater discharged from such a plant.

Waste Management and NMED agreed that the waste wasn’t hazardous or radioactive, he wrote. Shimic said he understood that the department and IMH Financial Corp., which owned the well site, had decided that any arsenic and radium in water or waste material from the wells was well below the limit the landfill could accept.

Arsenic and radium occur naturally in groundwater in many places, including New Mexico.

The loads were dumped in a lined landfill cell, and any leachate, or liquids produced from the waste in the cell, are handled according to an NMED-approved plan, Shimic wrote. He said the landfill generates little leachate because of the dry climate and procedures designed to minimize its production.

Also, Shimic wrote that Waste Management uses leachate for dust control only over the lined landfill and has restrictive requirements such as dilution before application.

He said NMED should close the investigation.

The department will evaluate the response and decide whether to take any further enforcement action.