Good Luck, Good Planning

A new water source and a new treatment plant help a small central Wisconsin city keep up with demand from a growing industrial sector.
Good Luck, Good Planning

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In four short years, Abbotsford has gone from a small Wisconsin town running out of water to the site of one of the most sophisticated water systems in the state. As a result, the city has been able to meet the growing water needs of a burgeoning hometown meat processing plant, sustaining employment and the local economy.

But the transformation was no snap. It took good fortune, effective planning, creative thinking and hard work on the part of the community's water treatment team. "The old wells were being depleted, with only a little rebound during spring," says Jon Strand of Short Elliott Hendrickson, the city's engineer. "We were starting to exceed the safe yield of the city's aquifer, and the projected water use indicated the problem would only get worse in the future. We were enforcing mandatory water restrictions on our customers."

Todd Medenwaldt, water utility supervisor, says the city looked at several alternatives. One would have connected Abbotsford and several other small communities to a pipeline extending east more than 40 miles to a water source on the Wisconsin River. "It was a great idea, but the other cities weren't on the same timeline as we were," says Medenwaldt, Wisconsin Rural Water Operator of the Year in 2000.

Then, through what Strand and Medenwaldt call a bit of luck and some kitchen table discussions, the utility acquired water rights to a fractured granite area a few miles east of town, found water, arranged financing, and built 12 new wells and the new treatment plant at a cost of $12.6 million. Sophisticated process

Started up in early 2012, the new wellfield and Eau Pleine Water Treatment Plant gave Abbotsford the margin it needs to meet present and future demands. The new infrastructure supplements the old well system and two smaller treatment plants — still in operation as needed — that use ozone and chlorination for treatment and disinfection.

In the new system, raw water drawn from the 12 vertical collector wells passes through a combined metering station, and is piped to the plant. First, the water flows down through aerated stripping towers filled with plastic ball media to oxidize iron and strip off radon gas. Next, the flow goes to a UTS treatment system (Tonka Water) that incorporates rapid mix for chemical distribution, a flocculation tank, and a compact inclined plate separator that clarifies the water.

Water overflows from the inclined plates into a tri-media filter (Tonka Water) containing anthracite, sand and garnet. The filter includes Tonka's Simulwash backwashing system, which uses air and water to clean the bed and conserve backwash wastewater. A settling tank allows recycling of 90 percent of the backwash water. A lagoon alongside the plant collects backwash sludge water, and the decant water percolates into the groundwater aquifer.

After filtration, the flow passes through an in-line TrojanUVSwift chamber (TrojanUV) containing a pair of bulbs. An uninterruptible power supply supports the UV system, ensuring that it stays online even if a brief power flicker or outage occurs. A backup generator provides emergency power for longer outages.

Permanganate, ferric chloride, chlorine and polymer are added to remove manganese, turbidity and residual iron. The flow is then chlorinated in a Hydro Instruments gaseous chlorine system and dosed with liquid fluoride before it is pumped into the distribution system. The chemicals and chemical feed equipment are supplied by Hawkins Inc. All process steps are redundant, so the Abbotsford crew can run one side of the system at a time, while performing any necessary maintenance on the other side.

The fill stations for both chlorine and fluoride are outside the building, and the chemicals pass through hatches into storage tanks. The arrangement means employees don't have to drag fill hoses through the building.

A SCADA system integrated by Total Control and containing some 1,189 connections with PLCs (Allen-Bradley/Rockwell Automation) monitors and controls the operation. The SCADA system ties in the other two treatment plants, the storage vessels, and all wells, pumps, metering stations, and raw water lines outside the plant.

"We love it," says water system operator Josh Soyk, who can view the entire system from his station in the Eau Pleine plant control room. "It updates all data points every 15 minutes and downloads the data into spreadsheets that we can use for our required reports." The system also gives Soyk and Medenwaldt real-time video camera coverage of all equipment and well locations outside the plant.

Good fortune

The new system wouldn't have come to fruition if Abbotsford had not discovered the water source in the granite fractures. "The other options for increasing water production didn't pan out," says Medenwaldt, but the city took an interest in the fractured granite area, acquired water rights from the land owners, and after several dry holes, completed 12 successful wells, three of them exceeding 60 gpm.

In negotiating to obtain water rights and purchase property across some 500 acres near the Eau Pleine River, "We literally had discussions over the kitchen table," recalls Strand. "We were able to find water along the fault lines of the granite formations." Once the new water source was assured, the city proceeded with plans to use the water and pump it to a newly built treatment facility near the wellfield.

Of course it wasn't that easy. "The Wisconsin Department of Natural Resources classified the water as surface water, since most of the wells aren't cased and grouted very deep, and the water is subject to turbidity and exposure to weather," Strand says. That meant the city's two operators had to be trained and certified in surface water treatment, and since the new plant was to be fully automated, it would have to be manned 24 hours a day, seven days a week, for the first six months of operation.

As a result, Medenwaldt had to hire six certified operators on a limited-term basis. "We were able to sign up a few operators part time from other plants in the area," he says. "And we found another operator who was retired and three who were unemployed at the time. You don't find surface water treatment plants in small towns like ours. They're mostly in bigger cities."

Consent order

In another twist, the water utility and the city initiated a consent order with the DNR to ensure that, once settled upon, the plan for the new system would not change, and deadlines would be met. "Once we had our financing [in the form of grants from federal and state sources], we wanted to make sure we stayed on schedule with the new plan," says Medenwaldt.

What concerned the water team were potential changes in city governance. "The consent order locked in the plan and kept the goals in place no matter who the city leaders were," says Medenwaldt. "It made sure we all stayed on the same page."

And while the granite fracture discoveries, the financing, the temporary employees and the consent order were all significant, the most important development was the establishment of a pilot plant that demonstrated complex treatment processes for another water source that was under consideration.

"It was pivotal," Medenwaldt says. "The pilot plant was run on water from Elm Brook, which is about 90 percent wastewater discharge. We figured if the system could succeed on that water, it would be fine for the well water. The pilot unit was set in a semi-trailer and included rapid chemical mix, flocculation, sedimentation, tri-media filtration and UV disinfection.

"I think it provided a helpful transition for Todd and Josh," says Strand.

Medenwaldt fully agrees. "We had zero experience with this kind of system," he says. "It gave us hands-on training by trial and error. We got to learn what the various chemicals would do and in what amount. We had to take responsibility for the system; it wasn't like our other plants where you just dose the water with ozone and chlorinate."

Medenwaldt says it also helped to learn all the terminology of the new processes and procedures. As the new plant was being built, the temporary treatment plant actually went online supplying a portion of the treated water to the city.

As an additional cautionary step, the water team imposed a 30-day shakedown period on themselves once the plant was complete. The extra month allowed the staff to work through any hiccups. "Plus, we wanted to make sure the SCADA system did what it was supposed to do," says Medenwaldt. "We needed to trust it."

Learning the ropes

Medenwaldt says the key to success has been learning how to "marry up" water from the different wells. The new wells (four near the plant and eight a couple of miles away near the river) produce varying water quality, especially with iron and manganese and turbidity levels.

"We've had to learn how to blend the water supply and manage our chemical usage," he says. "It doesn't make sense to go on steroids (chemically) at one point, and then add nothing at another."

Another key is solids carryover: "The rapid mix flocculation tank and the clarifier [inclined plate settlers] are critical. It's an area of the plant that either makes or breaks the operation. It's no secret: If the front end of the plant is not running, we've got no chance."

So it's not only a quantity issue; it's also a quality issue. Standing at the floc tank and looking at the reddish-brown skin forming on the surface, Medenwaldt moves alongside his inclined plate settler and cups a handful of crystal clear water coming over the weirs. Then, after the chlorine contact tanks and clearwell reservoir, he checks out the turbidity meter, which reads a value from all the plants. "If it's more than 0.3, we can't ship it to the public," he says. "But that doesn't happen very often."



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