Peralta council updated on sewer system


Peralta residents might pay $45 a month for sewer service in the future, but it could be the difference between clean or contaminated drinking water.

Peralta residents might pay $45 a month for sewer service in the future, but it could be the difference between clean or contaminated drinking water.

Clean drinking water depends on how well sewage is managed, especially in the Rio Grande Basin where the water table is high, said Clayton Ten Eyck, a Molzen Corbin engineer at the Peralta Council meeting Jan. 8.

He presented councilors with a preliminary engineering report on a waste water collection system in Peralta. Councilor Joseph Romero was not present at the meeting.

"It's documented quite well that the Rio Grande Basin, particularly in this area with the concentration of septic tanks — some that are permitted, some that are not — there's still cesspools that are known, and all of that stuff is contributing to the underlying groundwater," Ten Eyick said. "Pretty much, for the town of Peralta, all of the drinking water that is supplied is through relatively shallow groundwater wells, so there is a potential for contamination there, and that potential also stretches up into Bosque Farms."

Protection of the water in the area is considered the highest priority in the latest 2009 Valencia County Regional Master Plan.

There are about 1,200 septic tanks in Peralta, but only 830 of the tanks have permits with the state, said Ten Eyck. However, Peralta doesn't have a waste water treatment plant, and building one would be costly.

Fortunately, Peralta has the opportunity to connect to the Bosque Farms sewer system, Ten Eyick said.

"One of the big benefits as it stands right now for Peralta is that by orchestrating and cooperating with Bosque Farms, you can take advantage of some of the infrastructure that they currently have in waste water treatment plant capacity," he said.

The Bosque Farms plant has a 500,000 gallon-a-day capacity and is only using 200,000 gallons per day, however, the plant would likely need a second clarifying tank.

The Bosque Farms system has one clarifying tank with perimeter pre-treatment basins that empty into it for the final treatment before discharge. If a problem arose, the plant would have to shut down for repairs. With a second clarifying tank, operations would not be interrupted, said Ten Eyck.

"With the concentric configuration, you can't take any component of the plant down for maintenance, upkeep, those type of things," he said. "Without the redundancy, if there's ever a failure, or a need for maintenance, they don't have any back-up."

He said the tank would cost Bosque Farms about $10.9 million.

Molzen Corbin looked at four main alternatives for collecting sewage within Peralta that ranged from a gravity sewer system to STEP, which is Septic Tank Effluent Pump, a vacuum system, and a low pressure sewer system.

Both the previous engineering report and Molzen Corbin's latest assessment recommends the low-pressure grinder pump system because of the low water table. It is also less costly.

Grinder pumps are installed underground, and only a 2-foot wide dome is above ground on the residential property.

The total build-out cost was originally estimated at $37 million by another consultant, but Molzen Corbin said they could fulfill the contract for about $21.4 million as one project, or 10 to 15 percent more if done in phases.

If the project is done in phases, the first phase would install the main transmission pipe along N.M. 47 from Molina Drive to Chughole Lane to connect to the Bosque Farms plant, and would install 250 grinder pumps to residents in those areas.

Construction is slated to start in the spring of 2015 and Phase I could be completed within the following 12 to 18 months. The cost for Phase I is about $4 million.

Funding sources being considered include legislative appropriations and loans. A loan from the New Mexico Environment Department Clean Water State Revolving Loan Fund is attractive because it has very favorable interest rates, Ten Eyck said.

"And periodically, they even have subsidies. However, that's EPA-backed money, and if it's federally backed money they do require environmental (investigations)," he said. "In addition, we'll need to do some environmental (investigations) for the (N.M.) 47 corridor because what's been cleared previously was for roadway drainage, not necessarily utilities."

Other funding might include allocating more of the town's gross receipts taxes to the project, using an increase in property taxes dedicated to the project or a homeowner hook-up fee of $3,500.

The consultants suggested that some type of payment plan could be developed for homeowners who don't have $3,500 up front for the grinder pump installation.

The $45 monthly residential sewer service rate was calculated using what Bosque Farms residents pay for sewer service. The bill was broken down to a $30 sewer fee, which is about what Bosque Farms pays, a $5 Bosque Farms surcharge and a $10 Peralta surcharge.

However, no one knows yet how much Bosque Farms will actually charge for the service.

"At this point, the biggest component is going to be driven by the memorandum of understanding with Bosque Farms, which is going to identify what they're going to charge on a monthly basis as well as if there is going to be a surcharge," Ten Eyck said. "At this point, from a planning perspective since we don't have those numbers, we've taken a stab at it."

The next step is a public workshop at the end of the month or in early February, so residents can contribute to ironing out the details to finalize the engineering report.

-- Email the author at