While Lagunitas School District's contract with French Ranch remains mired over who would own and operate a joint wastewater system, Lagunitas School Board trustees agreed this week to explore an alternative septic plan.

Before a crowd of roughly 150 people, trustees on Tuesday heard a proposal to install a recirculating sand-filter system that could replace the school's failing septic systems without involving the controversial subdivision.

Although the engineer, Peter Lescure, said sand-filter technology has none of the drawbacks and most the advantages of the proposed pond-based system, trustees refused by a 3-1 vote to consider quitting their contract with French Ranch in an open meeting.

In requesting the vote, maverick trustee Richard Sloan said the agreement between the board and the developer opened the school district to unknown liability and created too much controversy for the board to move forward with any project.

"Since the contract was prematurely formed," Sloan reasoned, "I don't think it's premature to end it."

But the school's legal counsel, Suzanne Reed, suggested the board should not even entertain the idea of backing out of the contract in front of an audience that included the French Ranch developer, Bruce Burman.

"I would never advise a school board to publicly discuss rescinding or breaching a contract," Reed said.

Instead, the board will continue to explore whether the pond-based system known as AIWPS can be owned and operated by a special district or community service area that includes the school and the subdivision.

"I think in a month from now, we'll know a lot more about AIWPS and where we're going," said trustee Jeanne Marlow, explaining her vote against abandoning the contract.

Meanwhile, the board has some more time to explore whether the wastewater technology Lescure presented this week is as environmentally friendly, cost-effective, and trouble-free as he proposes.

In his presentation, Lescure described the system as an improved septic system: Sewage would be collected in an underground tank, repeatedly pumped through an underground sand-filter, then disinfected with chlorine or ultraviolet light and ultimately disposed through drip irrigation lines beneath school grounds.

The advantages of such a system, Lescure said, are its limited use of land, its relatively fool-proof design, and the quality of the treated water.

"It's so simple, it doesn't really require a certified operator," Lescure said. "One of the chores is going out to pick the weeds off it."

However, water produced by a recirculating sand-filter has not been certified clean enough by state health officials for reuse on school grounds. State water authorities have yet to approve drip irrigation leach fields for a school in the San Francisco area, and Lescure based his presentation and cost analysis on second-hand studies of the school's soils.

After his presentation, Lescure was quizzed by the district's representative, Jim Walton, who questioned whether the school property's high water table would bring puddles of sewage to the surface of the playing fields.

Walton also asked whether backup systems or storage tanks would be required if a power outage closed the school.

"No school, no sewage," replied Lescure, who insisted that any wastewater surfacing on the rain-soaked playing fields would contain no more bacteria than found in any other puddles.

But although similar systems have been installed at a Vacaville church and a Half Moon Bay golf course, Lescure conceded it might take a concerted effort to get state and county authorities to approve it for a Marin public school.

He said he has already asked the Regional Water Quality Control Board to give him some indication of whether they would consider the system for this situation. "I'm trying to get concept approval out of them first," he said. "I know time is money."

"I should think the whole community can squeak loud enough to get some grease," he added.

Lescure estimated it would cost the district about $300,000 to build the sand-filter system, as opposed to $375,000 for the pond-based system.

The sand-filter system would cost $15,000 a year to operate, he estimated, while the district would be contractually obligated to contribute $5,000 a year to the pond-based system.

"This is a very general estimate," Lescure told the board. "It's a credible, believable estimate. It's not a line-item estimate."

The board will next hear a wastewater presentation on Oct. 21 by Questa Engineering, the firm that designed a mound septic system for the school and conducted the soil investigation Lescure used for his presentation.

Walton said Questa's sand-filter system differs from Lescure's proposal only in how the effluent is disposed of. Instead of using drip irrigation lines, he said, the Questa system sprinkles the effluent over a mound.

Walton told The Light the advantage of the Questa proposal is that the mound design has a history of county approval, which considers drip-irrigation leach fields "experimental."

Furthermore, Walton said, Questa engineers have better knowledge of the school's soil and the soil on neighboring property, which he suspects would be needed for leach lines if the playing fields aren't available.

Once Questa's engineers review the Lescure proposal and present their alternatives to the school board, trustees should have enough options to make an informed decision, he said.

To help trustees arrive at their choice, Save The Valley committee presented the board with a petition signed by over 300 Valley residents opposed to the AIWPS facility or to working with the French Ranch development.