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$13.5 million arsenic filtering plant goes on-line
Mary Grace Houlihan Lathrops Principal Engineer shows some of the electrical paneling in the citys new $13.5 million water treatment facility on Louise Avenue. Located on the eastern edge of the city, the facility will filter arsenic from the groundwater produced at five of Lathrops wells and distribute it back into the citys water system. - photo by JASON CAMPBELL

LATHROP – Purchasing a 12-acre parcel along Louise Avenue that at one time housed an Army Surplus outfit turned out to be a homerun for the City of Lathrop.

Almost five years ago the city negotiated the purchase of the property for $2.25 million – less than half of the original $5 million that the owner was initially seeking when it first went onto the market – with the hopes of using it as a centralized facility for a future system that would filter out arsenic from the city’s drinking water.

And just over a month ago the $13.5 million state-of-the-art system went on-line – with all of the funding coming from either a low-interest loan from the State of California or facilities fees generated by the issuing of building permits.

Meeting necessary compliance deadlines set by the Federal government, said Interim City Manager and Public Works Director Stephen Salvatore, was the driving force behind the undertaking.

“Roughly 70 to 75 percent of the city’s water is groundwater, so those levels had to come into compliance – we really had no choice,” Salvatore said. “We do utilize surface water that we have rights to but that’s much more expensive, so it was important for us to get this underway and get this completed.

“We have other wells planned right now but they’re a considerable ways out right now based on the development schedule. We have enough water to serve our needs.”

The project began more than two years ago when piping was laid from the site on the city’s eastern side to the five wells that were measuring above the federal standard for the naturally occurring element. The threshold was lowered significantly in 2006 and forced many cities throughout the region to scramble for ways to meet the new standards before strictly enforced deadlines.

A Revolving Fund loan from the State of California helped provide more than $9 million worth of financing needed to tackle a project like the one that Principal Engineer Mary Grace Houlihan was drawing up, and provided the seed money to move forward with the early underground work.

Early on, then-City Manager Cary Keaten acknowledged the expensive nature of filtering arsenic from water (he would later leave to assume the top post at the Solano County Irrigation District) but noted that Lathrop deals with issues like saltwater intrusion from the Delta in the western areas of the city – making the practice of sinking new wells or drilling exploratory ones something that wasn’t necessarily feasible.

Transforming an open space into a maze of tanks and nozzles – designed to alter the pH level of the water during the filtering process – turned out to be not only the logical step but the most productive one.

According to Houlihan, a new process which adds ferric chloride to the water – an iron compound that bonds with the arsenic – then uses a sand-like media to filter out the heavier compounds and separates them into a sludge container is how the city will tackle the problem.

But the complex as a whole offers a lot more than just a water filtration system.

Minor renovations to an existing building on the property have allowed for the city’s maintenance and operations divisions to move from the dilapidated “house” they were using near the Lathrop Skate Park into a sprawling, centralized facility where saving space is no longer an issue.

“There were places all throughout town where things were kept because there wasn’t enough room,” Houlihan said. “This takes care of all of that and makes it easier for there to be an inventory of everything since it’s in one place. It’s a big help to those crews.”

And it could end up being a big help to local emergency personnel if the unthinkable – a levee breach – were to happen any time in the near future.

Because of its distant proximity (the site is nearly to the SSI Warehouse Complex on Louise Avenue) from the San Joaquin River, Salvatore said that the site has been outfitted with a complete duplicate server system that mirrors everything at City Hall.

A new SCADA (supervisory control and data acquisition) tower allows for communication options if needed, as many as 30 terminals can be set-up inside of the main office at the site – transforming it from a simple corporation yard to an emergency control center.

“It’s incredibly important to us because it’s outside of the 200-year flood plain, whereas City Hall is not,” Salvatore said. “It has the capacity to become an emergency command center. We have a massive generator out there, obviously the treatment plant, and phones and computers could be plugged in if they needed to be.

“We could accommodate any agency that needed to be there.”

The debt service for the loan will be incorporated into the existing water fee rate structure and split up among ratepayers.