(Originally published in the January 2009 Housing Journal)

Advanced Treatment Systems Require Knowledge of Electrical and Plumbing Codes

During a meeting December 2nd with representatives of the Construction Industries Division and NM Environment Department Liquid Waste Program, the issue of septic installers performing electrical connections for Advanced Treatment Systems (ATSs) came up.

Please remember — that unless the electrical components (e.g., blowers and pumps) are “plug-ins” an electrical journeyman must make all connections. If the installation is a retro-fit it will require an electrical permit in addition to the NMED permit. If the installation is at the time of new construction or remodel, the electrical permit for the structure will suffice for the installation of the ATU.

NMHBA has also heard from one of its builder members about a plumber installing a water softener on a new home with an ATS who insisted upon plumbing a line for the backflush directly into the ATS. This violates Liquid Waste Disposal Regulation NMAC, and NMED could issue a Notice of Violation to both the contractor and homeowner. The concern is that salts all work to some extent as an antibacterial agent, and introducing salts into a septic system can result in killing the good bacteria. Additionally, the salt may increase the specific gravity of the wastewater, reducing the effectiveness of physical separation of solids, and may clog small air orifices. Discharging water softener waste into an ATS may void the manufacturer warranty.

Here is the wording of the Liquid Waste regulations: Waste from a water softener unit shall comply with the following.

(1) Softener waste may be discharged to a conventional treatment unit. If the waste is not discharged to the treatment unit, the waste may be disposed in accordance with other applicable regulations.

(2) For new construction utilizing an advanced treatment system, the softener waste shall not be discharged to the advanced treatment unit. The softener waste shall bypass the advanced treatment unit and discharge directly to the drainfield or be disposed of in some manner acceptable to the department and meets all other state and local regulations.

(3) If a water softener unit is installed at an existing residential or commercial unit utilizing an advanced treatment unit:

(a) the current liquid waste permit shall be amended to reflect the installation;

(b) a written notice shall be submitted to the maintenance service provider of the advanced treatment unit; and

(c) either a demand-initiated regeneration control device (DIR device) shall be installed or the softener waste shall bypass the advanced treatment unit.

(4) If an advanced treatment unit is to be installed at an existing residential or commercial unit with an existing water softener, the installation shall be done in accordance with the permit.

Wastewater TAC Actions May Affect Cost of Select Liquid Waste Systems

The December 16th meeting of the Wastewater Technical Advisory Committee (WTAC) resulted in two recommendations from the WTAC that may increase the cost of ATSs and alternative dispersal systems.

The first recommendation came out of a discussion of Low Pressure Pipe distribution systems. The WTAC suggested the Liquid Waste Disposal Regulations should be requiring a maintenance contract for all treatment systems that have mechanical or electrical components (like pumps). Current regulations require only owners of ATSs to keep a maintenance contract in force, but do not require the same of alternative dispersal systems like dosing fields where the effluent is released all along the drain field length either on an as-created or timed basis. The cost of a maintenance contract for just a dosing dispersal system requiring only an annual inspection of any pumps and timers is estimated to range between $100 – $300 per year, based upon how close the installation is to a maintenance provider.

The second WTAC recommendation has the potential to cost between $500 and $1,500 per ATS. The WTAC approved a recommendation to change the Liquid Waste Disposal Regulations to require a full-size “trash tank” ahead of all ATS systems, and full-size integral settling tanks in ATS systems that won’t work efficiently with a “trash tank”. The WTAC expects this requirement to be drafted into the regulations when they are up for re-draft or amendments on other issues. The concept is that since an ATS is being placed upon a “challenged” site that does not have either sufficient lot size or has poor soil conditions, there needs to be a “fail-safe” component added to prevent health hazards should the ATS fail to function for any reason. A “trash tank” would provide at least a minimal treatment of the effluent prior to treatment in an ATS, and therefore no “raw sewage” would be able to cause pollution.


Other WTAC Actions

The WTAC also made recommendations on:

  • Eljen GSF has requested to be given secondary treatment approval because they assert their product performs as a “bottomless” treatment unit, providing for additional effluent treatment in the drain field area. Eljen is already approved for drain field use, and is already given a 30% “credit” for their alternative disposal technology. A lengthy discussion ensued about how to sample the effluent to confirm the additional treatment in a “bottomless” system where the water has already leached into the dirt. Ultimately the WTAC determined that Eljen already gets the maximum drain field reduction, and if they wanted to get the lot size reduction credit, they would have to show how their product reduces the nitrogen in the effluent, and where their systems are to be sampled.
  • The WTAC also engaged in a lengthy discussion of how many experimental systems each approved manufacturer could install, and how many should have to be sampled monthly for their required data acquisition to achieve full approval. The final recommendation was to allow six to 12 experimental units to be installed, subject to NMED restriction of the permit locations to full-time occupancies. All of the experimental units will have to be sampled so the manufacturer couldn’t choose which units to include or exclude from the data submittal.       The WTAC also commented they expected the NMED permitting process to include requirements for contingency plans for how the manufacturer would deal with repair or replacement of the experimental system should the sampling process show the unit(s) failed to operate in accordance with NMED effluent limits.



  • The WTAC took immediate action in support of a letter from Carlos Romero, NMED Environmental Health Division Director. The December 1, 2008 letter alerted the NMED Field Offices that a flexible connector/gasket is now required on outlet pipes from concrete tanks.       This action was taken because there have been many reports of leaks where the 4-inch PVC pipe is inserted into the 5-inch opening in the sides or ends of concrete tanks. The WTAC suggested NMED also require the gasket on the inlet pipe, even though that connection is higher up on the tank and should not be as prone to leakage.