Case Studies

Active Mixing Helps Rural Utility Solve Ice Buildup Problems

It is said that water bodies, like human bodies, require good circulation to function properly. Quiescent waters in potable water storage tanks can cause problems such as thermal stratification, biofilms, excessive disinfection byproducts and disinfectant residual loss. Ice formation in distribution system reservoirs is another challenge for water utilities in northern climates during winters. Thick layers of ice often form at the surface in storage tanks during prolonged periods of subfreezing weather.

Upstate New York Town Cuts THMs in Potable Water System

Concerned about levels of trihalomethanes (THMs) in the town’s potable water storage tank, water utility officials in York, N.Y., took advantage of a tank rehab project to assess their options. The overall goal was to provide high-quality drinking water, while also meeting the U.S Environmental Protection Agency (EPA) Stage 2 Disinfectants and Disinfection Byproduct Rule (DBPR) of 80 micrograms per liter (ug/l) or less at the last point of distribution.

Reducing Electrical Grid-Powered Aeration Use and Costs in Reactor Basins

Electrical-grid powered aeration in reactor basins at activated-sludge wastewater treatment plants (WWTPs) enables digestion by mixing and oxygenating the wastewater. The purchase of electricity to operate the aerators is a major part of operational expense. The use of electrical-grid power also increases the carbon footprint of WWTPs due to the associated greenhouse gas emissions, thereby contributing to global climate change.


Mixers Remediate Wastewater Odor Problem

Garretson, S.D., is a rural and agricultural community 20 miles northeast of Sioux Falls with a population of 1,166. Every spring, the town suffered through an “odor event” from the wastewater treatment plant.

“For several weeks, odors would roll over the whole town when the wind was from the right direction,” said Craig Nussbaum, utilities superintendent for Garretson. “We work on limited funds, so there wasn’t much we could do. We hoped the weather would take care of it.” Weather being weather, of course, it rarely cooperated.

Mixers Help Restore Pagosa Springs Potable Water System

Located in the high desert plateau of southwestern Colorado, Pagosa Springs is famous for its geothermal hot springs, which draw visitors worldwide to soak in the mineral-rich water. The Utes called the sulfur springs “Pah-gosah,” which means “healing waters.” One might say the town’s potable water system is healed now as well.

Rochester, Minn., Solves Ice Problem in Potable Water Storage Tanks with Electric Mixer

During the winter months, average daytime highs in Rochester, Minn., hover in the mid-20s (°F). Such prolonged cold has taken an annual toll on the town’s aboveground potable water storage tanks. Ice buildup sometimes measured as much as 2 ft thick inside the larger tanks, chipping away at paint on the interior walls and causing extra maintenance and expense.

Fun in the Sun

Along the banks of the Columbia River northwest of Portland, Ore., the City of St. Helens has seen the growth of several industries during its 160-year existence: lumber, mining, quarrying, manufacturing and shipping, as the city was originally established as a port. The city and its industries are used to working together in many ways for the benefit of the community. One of the more unique collaborations is that St.

Poised for Future Economic Growth

Throughout its 160-year existence, the city of St. Helens, Ore., has worked closely with its industrial residents for the benefit of the community. A recent project that teamed the city wastewater treatment plant with the local paper mill cut energy costs and earned a rebate from the electric utility and an award from the state for industrial energy efficiency.

Lagoon Retrofit Solves Short-Circuiting Problems

The 100-acre facultative lagoon system at the Iola, Kan., wastewater treatment plant was plenty big enough to meet the needs of the community: a population of about 5,700, plus a local candy manufacturer. However, the design used only about a third of each cell, and over time a variety of water quality issues accumulated, starting with short-circuiting.

Mixers Cut Costs, Odors in Ohio Wastewater Treatment Plant

In the Buckeye State, the village of St. Henry, Ohio, is bucking the trend of many rural farming communities. Instead of losing residents and local businesses to bigger cities, this community 40 miles northwest of Dayton is growing. Local industries such as turkey processing are expanding as well. Consequently, the city of 2,700 was outgrowing the capacity of its wastewater treatment plant.

Platte River Power Authority Restores Cooling Reservoir

Platte River Power Authority, which generates and delivers electricity to Fort Collins, Colo., and surrounding communities, puts a premium on cost-efficient energy and environmental responsibility. As a result, the not-for-profit utility’s coal-fired power plant, Unit 1 at the Rawhide Energy Station, is one of the 10 best-utilized plants in the United States, according to Electric Light & Power magazine. The plant operated at 93.9% of capacity in 2011 compared to an average 62% for all 520 U.S. coal-fired plants.

Wisconsin Wastewater Treatment Plant Cuts Costs with Mixers

The Twin Ports of Duluth, Minn., and Superior, Wisc., built on both sides of the St. Louis River where it enters Lake Superior, are together the largest port on the Great Lakes. Maintaining Lake Superior’s water quality in such a busy and diverse ecological area is the responsibility of many agencies, not the least of which are local municipalities. For the city of Superior (population 27,000), meeting permit requirements for its wastewater treatment plant had become expensive due to the aeration runtime required for treatment.

'Thumbs Up' For Michigan

The “thumb” of Michigan, outlined by Saginaw Bay and Lake Huron, is a peninsula rich in lakes, rivers and streams. Given the ecologically sensitive territory, smaller towns with limited resources can find it challenging to meet state mandated wastewater discharge permit levels. The Population 1,035 village of North Branch, about 30 miles northeast of Flint, faced problems of excessive phosphorous in its four-pond facultative system. To find out how to combat the problem and meet state discharge permit levels, wastewater treatment plant operator Ron Seaman got on the Internet.

Historic Concord Maintains Legacy of 'Revolutionary' High Standards

For the residents of Concord, Mass., high standards are part of their heritage. The “shot heard round the world,” fired in Concord, began the Revolutionary War and set new standards for democracy. Well-known 19th century writer Henry Thoreau mused about the quality of life at his nearby Walden Pond. In these modern times, Concord residents expect no less than high-quality drinking water, and Water/Sewer Division Superintendent Alan Cathcart is meeting that expectation without spending a lot of extra money.

Solar-Powered Circulation

Along the banks of the Columbia River, northwest of Portland, the city of St. Helens, Ore., and the town’s major industry, Boise Paper, share a wastewater treatment plant and even a U.S. Environmental Protection Agency-required National Pollutant Discharge Elimination System permit along with it. The two organizations work together closely to meet the mutual goal of operating the plant as efficiently and cost-effectively as possible.

A Swampy Situation

Circulation technology reduces blue-green algae in popular lake

Picture-Perfect Mixing

SolarBee mixers improve water quality for Yuma, Ariz., residents

North Carolina Treatment Plant Benefits from SolarBee Circulation

Wastewater treatment plant cuts runtime of high-horsepower aeration system

SolarBee Mixers Solve California City’s Chlorine Complaints

Storage tanks and reservoirs suffered from stratification and nitrification

Solar-Powered Circulation Improves Wastewater Mixing and Oxygenation Efficiency

New Hampshire Department of Environmental Services conducts studies to learn how solar-powered circulation increases operating efficiency, reduces grid power consumption and meets standards