Benicia City Council agreed Tuesday to fund a feasibility study of a project that ultimately could purify the city’s wastewater so it could be piped to Valero Benicia Refinery for use in its cooling towers.

But Council members also asked staff to examine some of the issues raised by the public and return with information and possible modification of the contract with Walnut Creek engineering firm Brown and Caldwell.

While ammonia would need to be removed, the water wouldn’t need to undergo reverse osmosis, the Council learned, a more expensive procedure that would have been required if the water was to be used in the refinery’s boilers.

City employees urged the Council to appropriate $814,043 in Wastewater Capacity Fees money for a contract with Brown and Caldwell for engineering services, including the feasibility study and environmental review that would position Benicia to apply for California Proposition 1 grant and loan money to complete the project.

“Time is of the essence,” several staff members said several times Tuesday night. That’s because Prop. 1 money is available on a first-come, first-served basis.

Water Quality Supervisor Dan Jackson said 39 water reuse projects are applying for financing. If all 39 are approved for financing, $42 million would remain available to underwrite other projects.

Benicia’s project would be the third-most cost-effective of those projects, involving one large customer and a comparatively short, 2-mile pipeline. But that’s not the key criteria, he reminded the Council. Timeliness and getting the project into the application queue are most important.

But Councilmember Tom Campbell said he’s heard staff members say a project is “urgent” and “we’ve got to do it now” before.

“Who’s accountable if there’s a mistake?” Campbell asked after a series of residents raised questions about the details of the project.

“What’s Valero going to do? I need to know more about the finances,” he added, pointing out that the city could spend more than $900,000 in preparatory work for its application, and participate in funding the $16 million construction phase, then hear that the refinery had rejected the project.

“I agree,” Mayor Elizabeth Patterson said, urging exploration of other ways to use the treated wastewater should the refinery decide not to participate.

Patterson reminded the Council of a more expensive proposal in 2008 to use reverse osmosis to clean the effluent to the purity needed for use in the refinery’s boilers. Ultimately, that project was set aside because of the cost, but preparatory work led to data that might be incorporated in the new feasibility study, she said.

“I’m disturbed the scope of work doesn’t acknowledge the work done,” she said.

Aesthetics also need to be considered, Patterson said.

On the other hand, she said, the initial expenditure “is a good investment,” and even those who expressed doubt about other portions of the project approved the bottom-line purpose: to redefine wastewater as a new water source for Benicia.

Jackson told the Council that California’s current severe drought isn’t surprising — the state has a history of droughts dating back to 1895. “We have droughts and floods. The current drought has focused our attention, but the situation we are in now will recur,” he said. “We live in an area prone to drought.”

The project would produce 2,200 acre-feet, or 717 million gallons, of recycled water annually that Valero could use in its cooling towers. The refinery uses 4,800 acre-feet, or 1,564 million gallons, each year for its operations, and Jackson said the company isn’t in a position to make many cutbacks.

The city normally expects to get at least 6,785 acre-feet of water from the State Water Project, though last year state officials decided to release no more than 5 percent of the amount for which the city had contracted. Solano Project water accounts for 2,138 acre-feet and Lake Herman can provide the city with 1,031 acre-feet.

Jackson said the water reuse project would become a fourth water source of 2,200 acre-feet a year. And, he added, it would reduce imported water by more than 20 percent, meaning saved water could be banked at Lake Berryessa for both the city and Valero.

He said the project would build on what was produced during the research done for the previous project, and would help Benicia meet state water quality objectives.

More importantly, he said, it would improve the city’s water reliability and security, a priority after the State Water Project’s limited allocation release that forced Benicia officials to spend $900,000 on water purchases last year.

By eliminating reverse osmosis and ultraviolet light disinfection, the project would be more economical than the one proposed in 2008, Jackson said, and some of the previous information — verifying the pipeline alignment and portions of the earlier environmental review and feasibility study — might be incorporated into the Brown and Caldwell scope of work.

In addition, an existing storage tank partway between the wastewater treatment plant and the refinery might provide adequate storage, he said, since wastewater is treated mostly during the day but the refinery is an around-the-clock operation.

The project would give the city something else to do with its effluent other than pouring it into the Carquinez Strait, Jackson said, adding that state regulations governing that practice are evolving, and criteria could be tightened.

Valero’s cooling towers, which control process temperatures, are critical to the refinery’s operation, and require water, which is recirculated as a conservation measure, he said.

The feasibility study would include a year-long sampling in 2016 of the effluent, to assure it is usable in the cooling towers through changing seasons. The environmental study, likely a mitigated negative declaration, also would be finished next year.

If the city and the refinery agree to continue and the grant and loan application are successful, the project would be designed in 2016 and 2017, and construction would take place in 2018.

Valero technical director Rebecca Sgambati said the refinery’s technical staff is advising city staff and offered its laboratories for any tests the city would need to run.

She said one of the most important documents would be the economic analysis of the project, and reminded the Council that Valero has pledged to support water reuse.

Most speakers Tuesday said they, too, favored the project, at least as far as making the effluent cleaner so it could be reused rather than dumped. But some weren’t sure about delivering it to Valero.

Marilyn Bardet, a member of the Good Neighbor Steering Committee, said she agreed “with everything said,” but added that “there are questions hanging over it.”

She asked why Valero wasn’t picking up half the tab for the study.

If there were time, City Manager Brad Kilger said, he’d be willing to broker a deal. But time is short and the wastewater capacity fees “are sitting there for this type of project.”

Reminding the Council that it has told staff to increase water reliability, Kilger said, “We can’t miss this opportunity.”

Andres Soto, who like Bardet is a member of several local environmental efforts, said water recycling “is the future.” But he expressed concern about Valero and its role in the community.

Good Neighbor Steering Committee attorney Dana Dean asked whether the wastewater money might be used to replace aging water infrastructure, but Public Works Director Graham Wadsworth said the capacity fund money is designated for making the city wastewater system bigger, and can’t be used to repair or replace old pipes.

When Pat Toth-Smith asked how the project would benefit individual residents, since the water wouldn’t be potable, Jackson said it would reduce the city’s need from 10,000 acre-feet of water a year to 7,800 acre-feet.

“We’re looking at water reliability,” Kilger said.

Mary Frances Kelly Poh urged public participation before the project reaches the environmental study stage.

As for other possible users, Wadsworth said astronauts completely recycle their water, purifying it so it’s acceptable as drinking water. Orange County is treating its water that thoroughly, too. In Texas, water is purified so it’s clean enough to pour into lakes, and in other places, effluent is cleaned enough to be used to flush toilets.

“We’re not there yet,” he said, saying the project would clean water to the fourth of six levels.

When it appeared the Council might want to delay its vote until more questions were answered, Vice Mayor Mark Hughes said, “I think staff did a great job.” He said the study would answer some of those questions. “I’d like to see this off and running.”

“Valero’s interested,” Councilmember Alan Schwartzman said. “We have to go through the process to get the information. … If everybody believes in recycling, we need to get started.”