Santa Fe County is considering building a pipeline to move wastewater from the Sombrillo area across U.S. 84/285 to a treatment plant owned by Santa Clara Pueblo.

Eventually, the effluent being pumped from Sombrillo — a small community just south of Española near Santa Cruz — could be used to water the pueblo's Black Mesa golf course, according to Santa Fe County Commissioner Harry Montoya.

Santa Fe County hired an engineering firm to evaluate four possible solutions for dealing with wastewater from the northern edge of the county, where proliferation of septic systems threatens to contaminate area aquifers.

The solution favored by the county would entail building a collection system to transport liquid waste from each household to a wastewater-treatment plant. Solid waste would continue to be collected in septic tanks that would need to be pumped out about every five years.

Engineers said the liquid waste could be piped either to the Santa Clara plant or the city of Española's plant.

Montoya said moving the waste to Santa Clara's plant makes more sense because it's closer and because the county would need an easement to cross pueblo land to get to Española anyway.

Montoya said Santa Clara Pueblo has expressed a willingness to cooperate with the county on the project.

But there are still several unknowns. One of them is how much the pueblo would charge the county for accepting its effluent at the plant.

Calvin Tafoya, CEO of Santa Clara Development Corp., said that detail hasn't been negotiated yet, but that the charge would be in line with rates being paid for similar services in the area.

"It would not be anything that would surpass that," Tafoya said.

Tafoya said the treatment plant that would be used to handle the waste from Sombrillo (and eventually nearby Arroyo Seco) isn't being used by the pueblo. It was developed to accommodate waste from businesses the pueblo planned to build at the intersection of N.M. 285 and N.M. 399 near the DreamCatcher Cinema, Tafoya said. But because of delays in finalizing those projects, the pueblo hasn't yet put the plant to use.

The capacity of the plant is 80,000 gallons per day. As is, it could handle all of the effluent produced by Sombrillo, but the plant would need to be expanded within about five years to accommodate wastewater from Arroyo Seco and projected area growth that would bring effluent levels to about 123,000 gallons per day.

If the system is installed, the minimum lot size in the area would decrease from three-quarters of an acre to a half-acre or possibly smaller, which could encourage more growth in the area.

The total cost of building transmission lines, expanding the existing plant and piping the treated water to Black Mesa golf course is estimated to be about $12.4 million.

The county has about $850,000 worth of capital-outlay money with which to start the project. Montoya said there is hope that the county could get some federal stimulus money for the project. But the county will likely need to secure a loan to complete the project.

How much residents would be required to pay to hook into the system depends on how the project is financed.

A preliminary report estimates the monthly cost per household could vary from as little as $11 per month, if only 10 percent of the money came from loans, to as much as $110 per month if the county had to borrow 100 percent of the money to build the system.

There are about 550 households in Sombrillo and another 250 in Arroyo Seco.

Amarit Khalsa, a resident who attended a recent meeting on the project on behalf of Sombrillo's large Sikh population, said the plan sounds like a good one.

"The proposal is very elegant and very doable and very cost-efficient," said Khalsa, who has been following the issue for several years. "I was impressed with their study and the fact that they looked at all the variables ... It seems like it would work better than everybody having their own septic tank and everybody doing their own thing."

The bottom line, Khalsa said, is that something needs to be done now before water contamination occurs.

"This is a problem that the whole valley has," he said. "If this is allowed to continue, there is a potential to contaminate groundwater and it could migrate and contaminate other areas. If the groundwater is polluted, everyone shares in that."

Montoya said more public comment will be sought, and more detailed agreements struck with Santa Clara Pueblo, before a final decision is made on how to proceed with the construction of the wastewater system. Montoya said he would like to see those things accomplished within the next six months.

Contact Phaedra Haywood at 986-3068 or phaywood@sfnewmexican.com