Los Lunas wastewater plant interruption triggers corrective action, regulator notice

Los Lunas officials said too much wastewater was diverted into the village’s activated sludge treatment process during Tuesday afternoon upgrade work, causing an overload that stripped away the bacteria the plant depends on to clean water before discharge. The interruption was serious enough to trigger immediate corrective steps and notification to regulators, while village staff worked to keep the wastewater system operating and rebuild the biological balance needed for treatment.

Village public information officer and deputy village administrator Nancy Jo Gonzales said the problem did not affect the separate drinking-water system and that residents were not being asked to do anything in response. Even so, village staff said the overload may have pushed discharged water past legal pollution limits, which is why the village began reporting the incident and taking corrective action right away. Officials said some partially treated water may have reached the discharge point while the system was recovering.

The corrective response included rerouting wastewater, increasing monitoring, and starting the process of restoring the beneficial bacteria, or biomass, that makes the activated sludge process work. That older treatment process first went into service in 1981 and was designed for 1.2 million gallons per day, according to U.S. Environmental Protection Agency permit materials. The village also operates a newer membrane bioreactor plant, completed in 2011 at a reported cost of $14,957,565, as part of its two-plant wastewater system.

The incident underscores how tightly Los Lunas has had to manage wastewater infrastructure as the village grows. EPA technical guidance says membrane bioreactor systems can maintain higher biomass concentrations and can replace parts of conventional activated sludge treatment, a reminder of why the village has continued modernizing its sewer facilities. New Mexico Environment Department records show the Los Lunas Wastewater Treatment Plant has remained under active regulatory review, including a 2024 public involvement plan for its NPDES permit, and a 2019 compliance evaluation inspection under the federal Clean Water Act permitting process.

The village has also been pursuing additional wastewater-related permitting work, including a proposed renewal and modification for the Los Lunas Wastewater Treatment Plant Effluent Loadout Station covering up to 96,000 gallons per day of reclaimed domestic wastewater to temporary reuse areas. With the Village of Los Lunas also having received $3,971,806 in a recent federal funding package, the interruption is another sign that the community’s utility systems are being pushed hard as officials try to keep pace with growth and capital upgrades.