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Cleaning Up San Diego Bay’s Dirty Marinas

Seabin sits in the water at Cabrillo Isle Marina in San Diego on Nov. 9, 2017.

Photo by Nicholas McVicker

Above: Seabin sits in the water at Cabrillo Isle Marina in San Diego on Nov. 9, 2017.

One corner of the Cabrillo Isle Marina used to be what General Manager Tony Reese called a cesspool. Reese stood on the dock and pointed to the small patch in the relatively clean water. Garbage, plant waste and gasoline used to get pushed into the corner by prevailing winds and tides.

“And at high tide, it gets pulled up off the rocks and it just becomes a little scum alley and then at low tide, go back and rest on the rocks and wait for the next tide to pull it up and make the mess all over again,” Reese said.

But for the past nine months, an industrial bucket sized pump, called a Seabin, has been anchored to a dock, sucking up anything that floats. It is like a large mechanical shellfish that constantly filters water.

“As you can see it’s a very quiet device a very small device, very unobtrusive,” Reese said. “Only about two and a half feet wide by about three feet deep. It has a small pump on the bottom. So it just, non-stop throughout the day, pulls in floating debris across the surface as well as petroleum.”

The device is basically five parts: an outer case that floats, an inner shell, a basket, a filter, and a pump.

The pump creates enough suction to pull the yellow internal shell below the water line. Water flows into the basket bringing along anything else on the surface. A separate petroleum filter captures fuel floating on the top of the water.

The device is located on the dock so the pump can be plugged in, which allows the Seabin to run around the clock.

“It’s really magnified in this location where it all collects. But there is floating debris throughout every marina in the entirety of the bay and throughout the ocean. And so this is kind of just the tip of the iceberg.”

Before the filter was installed, maintenance workers collected debris with skimmers and other tools, but that work was time-consuming and not effective.

Now the pump does the work and the filter is pulled up and emptied three times a day.

“The collection bag is designed to hold about 20 pounds so on an average day we’re pulling about 60 pounds out of the water,” Reese said.

The material ends up at the marina’s recycling station.

“We collect the items from the Seabin and we separate it into non-organic and organic type,” said Ray Gonzales, Cabrillo Isle Marina maintenance supervisor.

Gonzales pulled out plastic and other items starting with the large stuff first.

“We’ll sort out most of the ones that protrude out of it. All the plastic that’s more visible. Then after that, we’ll start the raking process for getting most of it. But we first go through for all of the plastic stuff,” Gonzales said.

Plastics go to the recycling bin and organic material is added to the marina’s compost pile.

Photo by Nicholas McVicker

Seabin maintains a low profile as it filters water at the Carillo Isle Marina in San Diego on Nov. 9, 2017

Marina tenants appreciate the cleaner water around their boats, Gonzales said, and they are frequently the first to report if there is a problem.

The clean water group San Diego Coastkeeper says these kinds of pumps can help the water quality in the bay. Matt O’Malley prefers to work on initiatives that keep trash out of the water, but he doesn’t ignore the fact that trash is already there.

“That trash and those solids and those oils, they do move around the bay. In those places they’re generally located in a tight spot so there is an opportunity to actually clean those localized spots, maybe easier than it is in the local bay,” O’Malley said.

The Seabin needs to be plugged in to work, although designers are working on a model that can use solar panels to power a pump.

The device has been filtering water at the Harbor Island marina for nine months. That trail expands to marinas in other California cities this month.

A San Diego marina is field testing a new pump that could help clean up water in areas where boats dock.


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