Engineers designed the 0.3 mgd Greater Bayfield Wastewater Treatment Plant (GBWWTP) with one goal in mind: to showcase environmentally friendly technologies as a state demonstration plant.
This plan evolved when two northern Wisconsin treatment plants wanted to merge their aging facilities into one. The city of Bayfield and Pikes Bay Sanitary District—both along Lake Superior with a combined population of 800 that quadruples during the summer tourist season—turned to Strand Associates Inc. of Madison, Wis., to explore funding and engineering options.
Located in an area with a low median household income, Bayfield and the sanitary district would receive major funding only if they incorporated green technologies. Ultimately, 70% of the project's $9.1 million total cost was covered by:
- A Wisconsin Department of Natural Resources (DNR) $4.5 million hardship grant from the Clean Water State Revolving Fund.
- A $500,000 Great Lakes Protection Fund grant for elements of the project that produce higher-than-required treatment levels.
- $1.4 million through the U.S. Army Corps of Engineers' new Section 154 grant program, which offers special appropriations to local governments that carry out water-related environmental infrastructure and resource protection projects.
The DNR approves permits and polices the quality of effluent leaving any treatment plant. To that end, the agency helped guide WWTP managers and Strand Associates through many of their choices in designing the facility. The state agency wanted the plant to be an environmentally superior facility—fitting, because the plant is so close to Lake Superior.
“The effluent is very clean,” says Tom Kovachevich, Bayfield's public works director. “If you hold it up next to a glass of tap water, you can't tell the difference.”
Strand added a host of technologies to meet the communities' goals of going above and beyond permit requirements:
- Cloth disk filtration from Aqua-Aerobics Systems Inc., which uses cloth filters in lieu of sand filters to remove any solids. These filters automatically backwash to remove sludge, which is then returned to the treatment plant.
- Reed bed sludge management, in which the sludge is pumped from the final clarifiers to an outdoor concrete tank in which reeds grow. The sludge is dewatered by the plants and remains onsite for up to seven years, eliminating the need to haul and spread it elsewhere (and earning some more green kudos by cutting down on fuel usage).
“These technologies make it a demonstration plant,” says Jane Carlson, PE, the Strand Associates project manager who worked extensively on the project. “There are only a few other plants like this in the United States with the combination of technologies and high effluent quality.”
The treatment plant serves as an educational tool to other communities and to the general public through tours. The plant includes other green elements such as energy-efficient lighting, day lighting, automated aeration controls, and efficient motors to go along with its treatment and sludge-management techniques.
“More treatment plants will be popping up that have environmentally friendly technologies,” says Carlson. “We're right on the cutting edge with this one.”
Project:Greater Bayfield Wastewater Treatment Plant
AEC firm: Strand Associates
Cost: $9.1 million including main pumping stations and force mains
Project delivery method: Design-bid-build
Size: 0.3 mgd; can be built out to 0.6 and 0.9 mgd
Annual O&M budget: $71,000
Wow factor: Sludge is removed just once every seven years
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