Lakeview’s aging lagoon aerator system was losing effectiveness and needed replacing. The village’s simple aeration system with rib-shaped array of final discharge pipes went online in the 1970s. the wastewater was aerated by a system of air pumps connected to weighted, perforated hoses on the bottom of one lagoon. The hoses emitted bubbles that supplied oxygen. After treatment, the water was pumped to a sprinkler system. Over time, the aeration system deteriorated. Leaves and debris clogged air hoses, algae mats built up, and neighbors complained of odors. The constant need to clean the aerators was becoming costly, and the Michigan Department of the Environment, Great Lakes and Energy put the village on notice to correct its problems.
In reviewing solutions, village manager Darin Dood was discouraged at the prices being quoted. For help, his team turned to Amanda White, a circuit rider from the Michigan Rural Water Association. Together, they learned the original aeration system manufacturer had gone out of business. In the meantime, the state Department of the Environment, Great Lakes and Energy put the village on notice to correct its problems.
In seeking alternatives, Dood and White first found only systems similar to the one already failing, at costs from $300,000 and 400,000. Then, while attending the National Rural Water Association conference, White met Lewis Titus, owner of Titus Wastewater Solutions, a vendor of aeration and mixing systems.
Dood contacted Titus. “Lewis was more than thorough in asking questions about our system, our needs, and how best to help us, given our limited budget,” says Dood. “We concluded that his system was a fraction of the cost of others, and would work better than those similar to what we were replacing. We were able to put the TITUS Twister FL system in for just over $100,000.”
Lakeview’s new system includes Titus Twister FL-6 units, designed for lagoons 8-12 feet deep; a 40 hp Howden positive-displacement, direct-drive blower with variable-frequency drive; and a 100-foot hose delivering high-volume, low-pressure air to two floating aerators made of rotationally molded, corrosion-free polyethylene.
The system’s air lift technology efficiently moves large volumes of water to provide mixing. Fine bubbles released through thousands of tiny slits in a cone-shaped plastic membrane rise through an oxygen transfer chamber, pushing water up while transferring oxygen to the water. The membrane diffuser is maintenance-free for a 10- to 15-year life and is easily replaceable.
Lakeview started with one blower. “We’re going to put in a second, so we can alternate them,” Dood says. “Then if one should one fail, we’re not out of business. Having a $30,000 pump is pricey, but if we exercise them both and alternate by month, we will be able to sustain that as a good, long-term plan.”
Titus helped the Lakeview team with the installation. Two of the lagoons now have the floating aeration machines. The Titus pumps are much more efficient than the old ones; a single unit can handle both lagoons at about half the RPM, using far less energy.
A large float head ejects the oxygenated water below the surface at high velocity. It directs the flow down and toward the lagoon banks at a 15-degree angle. The discharge is a 360-degree flow with no rotational torque. Because there are no moving parts or electrical power in the water, no boat-based maintenance is required.
The system is designed to pass rags without fouling. The intake floats just over the lagoon bottom, enabling it to pull water and solids up and then discharge the flow horizontally. This keeps diffusers from becoming buried in sludge.
The units are simply tied off to the bank with a rope and can easily be moved around the lagoon by hand, even while operating. This increases the area of in influence and results in complete mixing, reducing sludge deposits by 50-60% or more.
The aerators made a nearly immediate difference. “Before, there were ripples in the water,” Dood says. “Now, it’s like the difference between a calm swimming pool and a hot tub. The difference in turnover volume in that lagoon is insane!”
After about two weeks, there was significantly less matting. Within a couple more weeks, the foul odor was gone. As for sludge buildup in the lagoons, a survey by MRWA’s White before the new aerators were installed and six months after showed over 50% reduction, while maintaining more than 6 mg/L of dissolved oxygen.
Plant Type: Facultative Lagoon system
Details: Lakeview’s wastewater is treated inside two primary and one secondary clarifier lagoons, each measuring about 150 feet square and 12 feet deep.
Amanda White, Michigan Rural Water Association
Darin Dood, Village Manager
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