The town had previously relied on a gravity-fed lagoon treatment system, and later switched to the use of an aeration tank to handle the 85,000 – 200,00 gpd waste from its 338 households and dozens of businesses. The waste had to be initially piped to some 40 lift stations before being pumped to the headworks.
Port Austin wastewater plant supervisor Dale Jimpkoski, says this is where things regularly went wrong.
“The manual bar screen would catch stuff like shoes, bags and plastic bottles, and we would have to use a garden rake to clear it about three times a day. The pumps were constantly clogging up because of sanitary wipes and other hygiene products, slipping through the ½ inch – ¾ inch gaps in the screen.”
A Tsurumi KW-6049 automatic bar screen was installed at the headworks with the requisite controls and float system, for around $10,000.
Tony Misiak, process equipment sales manager at Tsurumi, says: “They asked us for a 2 mm bar spacing, which is very common for wastewater plants. The flow now comes from town and activates the screen, which automatically rakes out the solid contents. Disposable wipes will clog up pumps and automated valves, causing downtime and other issues — because they don’t disintegrate in water, it’s important they don’t get ground up, which creates a higher burden on the water system.”
The Tsurumi bar screen with in-line revolving rakes is expected to remove any solid matter lodged between or behind bars. It’s then transferred into a residue-collecting basket and then sent to a dumpster each month, saving the village labour costs.
Tsurumi’s KW mechanically cleaned front bar screens are designed for waterways up to 600 mm wide. They are constructed entirely from 304 stainless steel for high durability and corrosion resistance.
According to Tsurumi, running costs are extremely low, with all KW models powered by a three-phase totally enclosed 0.09 kW electric motor.
The KW-6049 — the highest-capacity model — can handle a throughput ranging from 357 gpm (at 1 mm bar spacings) to 982 gpm (at 5 mm bar spacings), the company adds.
A safety device will stop the motor immediately in the event of atypical operation.
“As a small community, Port Austin is a perfect fit for Tsurumi bar screens,” Misiak continues.
“The wastewater plant staff are extremely happy with how it’s performing — not least because its automated screening has enabled them to move past manual cleaning!”
For Jimpkoski, another welcome bonus of the Tsurumi system was the surplus of cash left in his budget that was used to build a portable shanty structure that protects the bar screen from the harsh Great Lakes winters. It is built on a 4 ft-square platform and provides easy access for inspection purposes, as well as room for a space heater to prevent the formation of icicles and ensure the screen performs optimally in freezing temperatures.
“Unfortunately, we were hit by a tornado this June that blew the shanty away,” Jimpkoski continues.
“But thanks to the savings enabled by the Tsurumi installation, replacing it won’t be the financial burden it might otherwise have been. We would definitely recommend this bar screen to other municipalities of a similar size — it’s doing a great job!”