Honorable discharge

Strand gives Bayfield a clean outlook

By Jennifer Pfaff

The distance around Lake Superior is equal to that between Minneapolis and Miami.

Its water and shores nurture a thriving tourism industry with a wide array of recreational opportunities.

Yet into that water flows thousands of gallons of treated wastewater carrying pollutants that can threaten the lake's health. As the tourism around Lake Superior grows, so does the amount of discharge entering the lake.

The city of Bayfield and the Pikes Bay Sanitary District recognized that problem and turned to engineering firm Strand Associates Inc. to help the city and district maintain their roles as stewards of the lake. With several grants in hand, the city and district invested $8.9 million into a wastewater-treatment plant that goes well beyond meeting state standards for pollutant discharge.

"Lake Superior is recognized as such an outstanding resource," said Jane Carlson, Strand's project manager. "It's so much a part of the tourism and recreation industries up there. They were really interested in continuing to protect it."

In the process, the Greater Bayfield Wastewater Treatment Plant and Conveyance System was hailed by the Wisconsin Department of Natural Resources as a model other communities can use to find cost-effective methods to protect their own water resources.

"They hope the project will demonstrate how a community can achieve high-quality effluent that goes above and beyond their permit requirements at an affordable cost," Carlson said. "We looked for technologies with the most bang for the buck."

	Project Name: Greater Bayfield Wastewater Treatment Plant and Conveyance System Location: Bayfield Submitting Company: Strand Associates Inc., Madison General Contractors: KBK Services Inc., Ashland; Utility Systems of America Inc., Evelith, Minn. Project Leaders: Jane Carlson, Strand's project manager; Margaret Guell, Strand's lead project engineer Engineer: Strand Associates Inc. Owner: Greater Bayfield Wastewater Treatment Plant Commission Project Cost: $8.9 million Project Size: 8,000 square feet Start Date: August 2004 Completion Date: January 2006 (substantially complete)

The city and district each had wastewater-treatment plants that were running out of capacity. Strand studied the situation and found that bringing the two together made sense.

Since its completion, the new plant achieved impressive numbers, averaging less than 5 milligrams per liter of organic matter compared to the state-standard of 20 milligrams. Where the state allows a fecal coliform count of 400, this plant typically generates less than 50, Carlson said.

The plant applies an aerated, biological-treatment technology that removes organic matter, nitrogen and phosphorous from the wastewater. After the material is removed, cloth-disk filters polish the discharge beyond state standards.

Ultraviolet disinfection occurs before the wastewater enters Lake Superior. The process also collects biosolids from the wastewater with reed beds, which only require sludge removal every seven years.

"The challenge was to select technology that wasn't the cheapest necessarily but affordable and had low long-term maintenance costs," Carlson said. "We knew they were getting grants for the initial purchase, but we wanted to make sure they weren't stuck with something that was expensive to operate."

The plant is designed for a peak flow of 1.33 million gallons per day, but it will average between 250,000 and 360,000 gallons per day, depending on the time of year.