Panning for Gold the RotoFlex Way
What if you could collect large amounts of valuable resources in the form of raw materials, heat, and chemicals for almost no investment or maintenance costs? What if you could also reduce the cost of water treatment?
That is exactly what is happening with the RotoFlex™ resource recovery strainer used in water-intensive process industries. Twenty-nine customers in North America, Europe, and Asia are already efficiently reclaiming valuables from process white water, which would otherwise have gone down the drain, or required major capital investment and treatment.
“Process white water is rich in raw materials and heat,” says Dave McGowan, technical manager at Kadant Solutions. “Reclaiming chemicals, fiber, fillers, and heat has been too costly in the past, not to mention the added expense from water treatment and disposal.”
The RotoFlex resource recovery strainer does not require electrical power. Conical media simply hangs freely from an upper support ramp, not attached or in contact with any part of the strainer below the ring.
The gravity-based process dilution feed flow from the distribution headers makes the media rotate. As the resource-rich process water passes over the media, the synthetic mesh flexes back and forth, capturing fiber and debris without the aid of a cleaning shower or scraping device.
How does a simplified resource recovery strainer work?
Fluid to the filter is supplied to a distribution header that feeds six stationary distribution header arms, mounted on an angle and parallel to the screen. A series of uniquely designed slots on each header delivers the feed at low pressure uniformly around the screen surface area.
The impact force from the distribution slots combined with the precisely angled flow results in the rotation of the screen assembly. Water that passes through the filtration medium collects and drains from the bottom of the unit. The retained solid material slides down the angled screen to the center, where it exits the strainer to a user-supplied collection tank. Heated water is sent back to a collection tank or other locations in the process for re-use.
Control “light”
To improve reliability, a measurement sensor for suspended solids is installed before the RotoFlex resource recovery strainer to support a managed control strategy. Adds Marcelo De Boni, applications at Kadant Solutions, “When you can see and analyze suspended solids values, you have a means to further optimize raw material and heat recovery and reduce strain on your equipment throughout your process. Adding a second suspended solids sensor in the filtrate piping, after the RotoFlex resource recovery strainer, enhances stable and reliable water supply. When suspended solids concentration hits the maximum set point, automatic valves stop the filtration process and send dilution water to chests in the recirculation loop at a reduced flow rate.”
Compelling returns
A linerboard mill removed non-critical machine showers from fresh mill water and switched to heated, filtered white water, made possible with two compact RotoFlex resource recovery strainers. Energy savings alone was over $3.5 million annually. An additional $450,000 in savings resulted from reduced effluent treatment.
Particleboard opportunity
A particleboard mill is evaluating two RotoFlex resource recovery strainers for a wastewater treatment system to reduce particles in the Bio Tank. Analysis and trials confirm that adding RotoFlex resource recovery strainers to the Bio Tank could nearly double the time between tank cleanouts from once per year to once every two years. And best of all, the return on investment would be less than one year.
Pioneering in food and beverage, wastewater treatment
Trial RotoFlex resource recovery strainers are available for food, beverage, wastewater treatment, and other resource-intensive applications. Wherever process water can be re-used, and raw materials like fiber, filler, and chemicals can be recovered, the RotoFlex resource recovery strainer should be considered.
