Numerous Ideas Over How to Expand Wastewater Plant Capacity

Petaluma’s wastewater plant is running at close to 75 percent capacity, largely because dairies and breweries are pumping in more waste than anticipated when the plant was being designed a decade ago.

More waste is good, in a way.

In means production is up and increased sales revenues for the city.

But because companies are charged for every pound of wastewater they discharge into the city’s sewer, many have long been pushing the city to reevaluate its fee structure while upping the capacity of Ellis Creek Wastewater Treatment Plant.

High-density waste is typically things like fat, grease, oil and beer byproduct that can clog the city’s sewer lines unless it’s pre-treated first.

On Monday, Petaluma Public Works Director Dan St. John gave a detailed presentation about ways to tackle the problem, but made clear that it would take another six months before any improvements are implemented.

Among his ideas:

• Change the rate structure for industrial users instead of fining companies that discharge more than their allotted share, 
• Increase how many pounds of high-density waste the plant can take,
• Upgrade and optimize the equipment that processes waste solids and look into reusing solids (Currently, some is already utilized as fertilizer, while more “toxic” solid waste goes into landfills.) 
• Install methane digesters that would convert solid waste into energy, then sell it.

St. John said the amount of high-density waste jumped significantly last September and has remained high, although he did not know why.

“It’s something we are investigating,” he said.

He reiterated that no matter what option was selected, it would first have to be studied, which could take another half a year.

“These are data-driven decisions. We can’t second guest it…But if our policies are causing our customers to go away, we can look at that.”

Lagunitas Chief Financial Officer Leon Sharyon said that he was happy the city was tackling the issue, even as he acknowledged that Ellis Creek did not have the capacity to process his company’s waste.

“We’re going to make the decision to pre-treat upstream at our plant, we can afford to do and it just makes economic sense for us,” Sharyon said, adding that the company put in 200,000 pounds of high-density waste into Ellis Creek last month.

(The plant is designed to take about 18,600 pounds a day from industrial users.)

“But in general, you don’t want for companies to wait to become our size before they decide whether they can even be here. Having a program in place and a structure which allows it be shared or borne by the industrial user will be pretty paramount for the commerce of this community.”

St. John got direction to continue studying the alternatives, even as some council members appeared somewhat frustrated about the many unknowns of embarking on such a project.

“You’re saying you need product (continued high level of industrial waste) to warrant improvements, but businesses need guarantees,” said Councilman Mike Harris.

Attracting food processors, especially organic companies, to Petaluma is one of the goals the city established in its economic development plan, released in 2010.