PLEASANTON — The city recently began installing a large filtration device to capture trash floating through Pleasanton's storm drain system to prevent it from making its way to the San Francisco Bay.
Known as the Koll Center Trash Capture project, the 10-feet-wide, 18-feet-long, 17-feet-tall concrete structure at the storm drain easement at 6900 Koll Center Parkway should become operational at the end of August.
“It captures everything from 5mm and up,” said Zach Crear, marketing director for BioClean, an Oceanside company that manufactures devices to clean stormwater. “To give you a perspective on that — like a cigarette butt and up.”
City officials said the device is connected to a 60-inch storm drain to collect floating trash and other pollutants before they reach the Arroyo del Valle and eventually the San Francisco Bay.
Approved at the March 2 city council meeting, the BioClean Trash Capture device will help Pleasanton meet National Pollutant Discharge Elimination System requirements to reduce the amount of garbage that flows from the city's streams and drains into Arroyo del Valle, explained Adam Nelkie, Pleasanton's senior civil engineer. Water from Arroyo del Valle ultimately flows through miles of waterways through Alameda County to the Bay.
At a price of more than $650,000, Pleasanton funded the project alongside Caltrans, which was required under other federal requirements to reduce trash that could enter storm drains from along I-680 and flow to the Arroyo del Valle.
This prefabricated device will capture trash ranging from bottles, plastic bags and fast-food wrappers that can get into the storm drain system from 92-acre acres that include the Bernal Corporate Park campus, portions of Bernal Avenue, portions of I-680 and the Bernal interchange, city reports stated.
“It’s a complete install-ready system,” Crear said. “They just drop it in and connect it to the pipes and after it’s activated, it’s ready to treat water."
According to city reports, the city looked at four trash capture devices approved by the State Water Board and settled on BioClean. The device fit the storm drain easement, met maintenance access requirements and had the lowest price.
The device — known as a Debris Separating Baffle Box — contains stainless-steel-screened areas for floating trash and a sediment box below to collect sand. Crews must clean it out two or three times a year.
“It’s pretty easy to maintain, because you can access the cages and the baffle cages with just a normal vacuum truck,” Crear said.
According to BioClean’s website, the device's "innovative screening system
directs floatable trash, debris and organics into raised filtration screens for dry state storage, which prevents septic conditions, odor, nutrient leaching and allows for easy removal."
In other words, said Crear, it can handle a high volume of water and trash, keeping them separated so that garbage does not sit in the water and smell and degrade.
Crear said trash collection devices have been around for decades, but this newer updated technology was created in the last five years.
Other cities, including San Jose and San Francisco, along with cities in Los Angeles and San Diego counties, use similar devices. Livermore has a “DSBB Separator” on East Stanley Boulevard, and other smaller trash capture devices are located in Dublin.
“They are all protecting the same watershed that goes into the San Francisco Bay,” Crear concluded.