The wastewater treatment plant in the city of Clyde, Ohio, managed to remove 37 tonnes of debris from an oxidation ditch, following investments into rotating drum screens to help remove excess plastics debris.
The treatment facility, that went online in 1986, recently completed this task after a week-long operation, which involved a large amount of manual labour despite using a vac truck. The same clean-out job is due to take place soon for Clyde’s second oxidation ditch.
“The wastewater treatment plant at the city of Clyde, Ohio, is immaculate,” says Paul Matrka from equipment provider, Smith Environmental. “Everything here looks brand new. It’s a real pleasure to visit.”
“Completely transformed”
The legacy of the debris is an accumulation over almost 40 years, but as treatment plant superintendent, John Biggs explains, the investment in new screens has “completely transformed” the intake process and has made life “considerably easier” for the plant’s equipment further down the line.
“Our new screens, made by Lakeside, have made a world of difference,” he said. “We are very pleased to be rag-free.”
Previously, only one of the two new screens is in operation at the facility, However, for storm events, which can suddenly send flows shooting up from 1.6 million gallons per day (MGD) to 6MGD in a very short space of time, that second screen is essential. Barraging storms, coupled with snow-melt in the spring and mountains of leaves in the fall, were a difficult test for the treatment plant, which is situated roughly halfway between Toledo and Cleveland). Currently, on a day-to-day basis and in storm events, the screens hold firm.
“Apart from large objects such as rocks and bricks, our old bar-rake screens didn’t capture that much,” added Biggs.
“The screens handle it”
“The rags would just work their way through to the oxidation ditches, creating problems all through the process, especially with pumps getting plugged. Dealing with the initial storm surge that picked up all the accumulated material used to be a real challenge, but now, despite several storm events, we’ve not had an issue at all. The screens handle it. Right down to pieces of debris the size of a cigarette butt, the Lakeside screens remove it; even some of the grit that attaches itself to rags is not a problem. We’re removing 1-2 cubic yards of debris per week. It’s fantastic.”
The stainless-steel constructed Lakeside Raptor Rotating Drum Screens remove plastics and other floatable material. These can have a detrimental effect on various areas of the treatment process, as mentioned previously by Biggs. Captured screenings are compacted, de-watered and washed free of most organics to approximately 40% solids. Volume is reduced by 50% and weight by 67%, thereby reducing disposal cost. Flow is directed into the screenings basket where fine solids are captured by a ¼-inch diameter perforated plate screenings basket. When the upstream water level rises to a high-level set point, the screenings basket begins to rotate for removal of the captured material. With the aid of the lower spray wash system, the debris is then removed from the rotating basket and falls into a collection trough. The debris is then removed from the trough by a central screw conveyor. The conveyed material travels up the inclined transport tube where the material is washed, compacted, and dewatered prior to being discharged into a debris container.
“There are always a few things to fine-tune when introducing new equipment,” continued Biggs. “With the screens, when running at the same time, which isn’t very often, there wasn’t quite enough pressure at first, but Lakeside was on the case immediately.”
Maktra from Smith Environmental concurred Biggs’ observations: “That’s one of the great facts with Lakeside Equipment Corporation; they really care about the installation. They have a wealth of design and engineering experience, so they stepped up straight away to make everything right with a booster pump.”
With each Lakeside screen having a capacity of 5MGD, the issue appears to have been resolved for now. However, Biggs and his team are keeping a watchful eye on the plant’s SCADA system during storm events. With just one screen required most of the time, there is also the benefit of rotating them once per month, with pressure-washing once per week as a preventative maintenance measure.
“Overall, the Lakeside screens are user-friendly and very maintenance-friendly,” concluded John Biggs. “We did plenty of homework, speaking to several operators in the state before making our investment. We firmly believed that Lakeside was the best equipment for the best price; and our decision has proved a very wise one for the plant and for the City of Clyde. They are the best thing we’ve done here.”
