Small Is Beautiful

A two-member team in Shannon, Ill., extracts award-winning performance from a small treatment facility built around aerated lagoons and rock filters.
Small Is Beautiful
Jason DeMichele, left, public works director and plant supervisor, and employee Dale Haring.

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Egrets and trumpeter swans may know more about the Shannon Wastewater Treatment Plant than the 757 folks it serves. These and other birds regularly visit the aerated lagoon plant, in the rural area in far northwest Illinois.

But public appreciation may be improving: The plant recently won Illinois Plant of the Year in Class 4 (for the smallest plants), awarded by the Illinois Association of Water Pollution Control operators, after nomination by the Illinois EPA and a thorough peer review. The local newspaper wrote about the award.

Plant supervisor Jason DeMichele, also the village’s public works director, says the award was quite an honor for his small town. “There are 674 Class 4 plants in the state,” he says. “Very few from our area of the state have been nominated before.”

Dave Mitchell, state operator association executive, says winning plants exhibit exceptional effluent quality, good general appearance, sound maintenance, adequate spare parts inventory, accurate record-keeping, excellent lab procedures and sampling protocol and effective emergency planning. They must also demonstrate safe operation and effective training.

DeMichele takes pride in the way the grounds are kept, the plant’s impeccable safety record (12 years without an accident), and the teamwork between himself and laborer Dale Haring. The facility has been violation-free since DeMichele arrived in 1995.

Simple system

The Shannon treatment plant, built in 1987, is an aerated lagoon system with a design capacity of 180,000 gpd (actual flow averages 83,500 gpd). Flow moves by gravity through the village sewer system and through the plant all the way to lift pumps at the effluent discharge to Lost Creek.

Wastewater first enters Cell 1 of the lagoon system. The cell measures 285 feet by 230 feet, is 12.5 feet deep and has 4.5 million gallons capacity. Oxygen is supplied to the cell by four Aqua-Jet II floating mechanical surface aerators, supplied by Aqua-Aerobic Systems and installed in 2008. Detention time in Cell 1 is 25 days.

Treated water from Cell 1 passes through a rock filter and then to the first of two settling ponds, after which it moves on to Cell 2, a smaller aerated lagoon measuring 230 feet by 140 feet, also 12.5 feet deep and with 1.88 million gallons capacity. It is aerated by a single floating mechanical aerator (also Aqua-Aerobic). Detention time is 10.5 days.

A second holding pond accepts the finished water, which overflows onto another rock filter and then is lifted by pumps to the outfall. The flow is aerated again at the back end of the rock filter. Detention time through the final rock filter, which includes three feet of rip-rap type rock structure, is about one day.

Close attention

Until the early 1990s, the plant added chlorine to the finished water before discharge, but there has been no need for that since because the effluent is so clean. The aerators are controlled by timers, which can be set on manual or automatic through an electrical control panel situated on a berm.

The facility includes a small laboratory where DeMichele tests for BOD, TSS, DO and pH once a month. The plant has an effluent meter (Gasvoda) installed in 2009, but no influent meter. DeMichele relies on old-fashioned eyeball observation to check performance most of the time.

“I visually check the lagoons every morning, seven days a week, 365 days a year, and check the numbers and the flow volume in the effluent meter to make sure the system is operating properly,” he says. In winter, he pays close attention to the mechanical components — the lift pumps in the wet well of the finish pond and the surface aerators — to make sure they’re operating properly in the cold conditions.

There has been no need to remove sludge from the ponds. He and Haring measured Cell 1 two years ago (using a Sludge Judge [Nasco] device) and at that time started researching biological enhancers. They got approval from the village board to begin adding 930 Municipal Lagoon Treatment, supplied by Mississippi Valley Pump (MVP). The enhancer contains micronutrients and a blend of organisms specially selected for the application.

DeMichele adds two 1-pound dissolvable packets per week to Cell 1. The material uses no chemicals. “Since we’ve seeded the lagoons, our settled water is clearer, so we believe the enhancer is working,” DeMichele says. They measured the cell again in spring to check levels. “Sludge removal would cost us big bucks, so we hope we can avoid that.”

Better aeration

The surface aeration equipment brought another significant improvement in plant operations.

“Previously, we had large, heavy aerators — they were monsters,” De Michele says. “The motors were inside housings and were under water. They required a crane to pull them out. For a small town like ours, a crane at $250 an hour is a pretty expensive proposition.”

The new surface aerators are much easier to maintain and have presented no problems in the six years since they were installed. “The motors are on top, and we use a small truck-mounted crane to pluck them out and service them,” DeMichele says.

Looking to the future, DeMichele expects to see more work on sewer and water line maintenance as old lines handle increasing pressures and additional flows. A 2002 state grant supported separation of storm and sanitary sewers, as well as smoke testing and spot repairs.

At the plant itself, DeMichele will investigate his sludge inventory and the possible need for solids removal from the holding ponds. Other than that, he and Haring plan to keep the snow shoveled, and grass mowed, and the safety fence around the property in good repair. It’s important to keep curious onlookers and stray critters away from the ponds and lagoons.

Except for those birds, of course.  

More Information

Aqua-Aerobic Systems, Inc. - 800/940-5008 - www.aqua-aerobic.com

Gasvoda & Associates, Inc. - 708/891-4400 - www.gasvoda.com

Mississippi Vally Pump, Inc. - 877/711-7587 - www.mississippivalleypump.com

Nasco - 800/558-9595 - www.whirl-pak.com



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