Town of Taos hears detailed update on wastewater treatment plant, Septic station and permit timeline

Paul Kennedy of Gallatin Operational Solutions gave a technical presentation to the Taos Town Council on the wastewater treatment plant’s operations, recent upgrades and planned projects, telling the council the plant serves the town plus Pueblo, El Valle de Los Ranchos and El Prado and that “they receive up to 30,000 gallons per day of septic waste.”

Kennedy outlined the plant’s evolution — original construction in 1974, capacity upgrades in 1985, process changes in 1995 and a membrane bioreactor (MBR) upgrade supported in 2011 — and described two permits that govern the facility: an NPDES (National Pollutant Discharge Elimination System) permit for surface-water discharge and a New Mexico Environment Department groundwater-discharge/land-application permit. He said sampling and testing schedules vary by constituent and permit requirement and that biosolids are currently disposed of at the Taos landfill.

The consultant explained the regulatory context: a 2019 EPA and state study led to proposed nutrient limits (total nitrogen and phosphorus) that, if implemented at once, would have required very expensive treatment such as full reverse-osmosis; that study estimated a capital cost in the tens of millions and a sewer rate impact on the order of $1,900 per household per year if implemented immediately. He said regulators and the town instead adopted a staged approach and that a preliminary engineering report (PER), with a roughly 20-year planning horizon, is now beginning to evaluate phased alternatives for meeting future limits while limiting rate shock.

Kennedy walked council through three levels of treatment upgrades from process optimization (dissolved-oxygen control, BAFL baffles and supplemental carbon dosing), to adding a post-anoxic zone using existing clarifiers, to building a new anoxic basin sized for the full plant. He described options in the PER for disposing or reusing effluent, including sending water away from the receiving arroyo/Rio Pueblo de Taos, building a reclaimed-water irrigation system and using evaporation or infiltration ponds to shift some flow from the NPDES permit to the groundwater/land-application permit.

Staff and Kennedy reviewed a prioritized “tier” list of repairs and smaller upgrades. Tier 1 items under way include ordering parts to repair the belt press, replacing failed blowers and compressors (with noted long lead times and out-of-state service travel), and fixing a failed wash-water pump. Tier 2 work includes phased membrane-module and cassette replacements for the MBR; Kennedy said lead times for membrane modules can be 76–80 weeks and noted the town’s 2023 order completed half the replacements installed in February 2024. He said cassette refurbishment lead times are shorter (about 10–20 weeks) and that some vendor service representatives will come on site to assist with installations.

Council members pressed staff and the consultant about costs, the upcoming PER timeline, and how septic receiving is handled. Kennedy described two options for the septic-receival issue: (1) relocate the septic receival station upstream into the collection system so hauled loads are diluted and released gradually, or (2) construct a large holding tank at the treatment plant to store hauled septic and feed it into the plant slowly. He said the septic station’s permitted intake is up to 30,000 gallons per day and that septic haulers are primarily from outside town limits.

Council and staff discussed regionalization, rate study timing and equity (whether out-of-town users should pay different rates or annex), and noted a forthcoming rate study that will evaluate options for recovery of capital and operating costs. Public commenters suggested technical fixes (for example, adding aerators on septic tanks) and asked council to coordinate with neighboring jurisdictions on connections and cost-sharing.

The presentation concluded with staff reporting that the PER will examine costs, construction and lifecycle estimates and that the short-term focus will be completing high‑priority Tier 1 and Tier 2 repairs while PER alternatives and effluent‑management options are developed.