Consultants outline groundwater, leachate and methane monitoring at Taos Regional Landfill; Cell 5 progress and permit renewal update

Matthew Earthman of Sauter Miller & Associates presented the town with a compliance update from the Taos Regional Landfill, covering groundwater, leachate and methane monitoring alongside project updates for a permit renewal, Cell 5 construction and a proposed regional recycling facility.

On groundwater, Earthman described six monitoring wells (MW‑1 upgradient, plus MW‑2R through MW‑6 along the south and west boundary) and a sampling program conducted semiannually under an approved Groundwater Monitoring System Plan. He said testing covers more than 100 constituents, including volatiles, pesticides and heavy metals. "We do see elevated chromium metal concentrations... this is naturally occurring," Earthman said, adding the New Mexico Environment Department (NMED) has accepted that characterization. He also noted a slow upward trend of nitrate in MW‑5: "the assessment monitoring level is 5 milligrams per liter... we have seen exceedances of that in the last few monitoring events," he said, but stressed concentrations remain below the groundwater protection standard (10 mg/L) and NMED has not required corrective action.

For leachate, SMA described five sumps, monthly monitoring and a compliance threshold of approximately one foot of leachate on the liner. Earthman said NMED requested construction of a lined leachate pond on the northeast corner as part of the pending permit modification. Regarding methane, SMA performs quarterly perimeter soil probes at 10 points and in-structure readings; methane levels have not approached the lower explosive limit at Taos.

Project updates included the permit modification and renewal intended to extend operation for an additional 20 years while allowing vertical and horizontal expansions (raising final cell grades ~15 feet in places). Earthman described extensive public notice (250+ certified mailings, radio and newspaper ads) conducted before submission and said SMA expects to submit the package by month-end; NMED will have three months to review and the overall process could take a year or longer. He reported that Frontier Development Inc. was awarded the Cell 5 construction contract in August 2026, but the contractor is experiencing liner‑supplier backlog and the preconstruction meeting is delayed until liner availability is resolved.

Earthman also described a regional recycling and composting study led by SMA with subcontractor Reftellus to evaluate capacity and financial options; the kickoff was the week of Sept. 7 with a 12‑month schedule for recommendations. Council members asked about steps that could impede the permit renewal (unaddressed NOVs) and emphasized diversion strategies to extend airspace life. Staff and council discussed potential capital investments at the landfill, such as a transmission line or hydrant for fire response and moving from generator-powered leachate pumping toward electric transmission or other long‑term solutions.