Traverse City Record-Eagle

May 12, 2013

Filter at East Bay Park to reduce E. coli


---- — TRAVERSE CITY — A new filter system at East Bay Park could help keep the popular swimming beach clear of a main culprit for E. coli contamination.

Raccoons have made themselves comfortable in the storm drains near the beach, and rain washes their feces into the bay. Storm drain cameras near the beach revealed hundreds of pounds of raccoon feces, said Sarah U'Ren, program director for the Watershed Center Grand Traverse Bay.

"It’s like a little Hilton spa hotel in the drain system over by East Bay Park," U'Ren said.

The Watershed Center, along with the City of Traverse City and Grand Traverse Health Department, closely monitored water quality at the beach for years to figure out the source of E. coli that's frequently forced swimmers out of the water. Officials posted two or three health advisories at the beach last summer and five the previous year, U'Ren said.

The Watershed Center, in conjunction with Traverse City, is tackling the problem with a $768,000 grant from the Great Lakes Restoration Initiative. A three-step filtering system expected to reduce bacterial contamination is being installed and should be complete by mid-June.

Through the new system, storm drain water flows through an oil and dirt separator to a three-section settling tank that catches heavier sediment such as cigarette butts and pine needles. The water from there goes through filters treated with an antimicrobial substance that kills bacteria.

"It doesn't use chemicals," U'Ren said. "(The filtering system) is coated with this substance that’s positively charged and on a microscopic level has sharp points and bacteria comes into contact with the sharp points. It’s like mini-little zapping thing."

Most of the storm drain flow will be rerouted to the south end of the beach, away from most swimmers, U'Ren said.

The majority of the beach water will be treated, except for a small storm drain that carries surface water from vacant land, said Tim Lodge, city engineer.

The three step-system replaces a single-component filter that caught trash, bottles, cigarette butts and organic materials. Lodge said it didn't directly impact pathogens.

Components of the new system will need to be replaced in five or 10 years, and it's unclear how much routine maintenance it will require. Officials will continue to monitor water quality.

"This is a big step in the right direction, and with that comes responsibility," Lodge said.