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Filter press elevates best process-water management practice at Ready Made Concrete

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A family-owned business established in 1993 with 5-yd., single-axle truck, Ready Made Concrete Inc. has grown to a fleet of 26 full-load mixers, serving decorative concrete interests in Salt Lake City and, more recently, commercial slab and wall contractors.

“Single- or two-truck deliveries were our maximum load size—it was a good fit for municipalities, small cities, little communities where there was a real need and demand for smaller loads,” says Ready Made owner Paul Philips. “We filled the need there and just grew.”

CHALLENGES

Located in an urban area, Ready Made has limited space on site to dispose of material. For years, plant staff used settling pits, which took up a large area and required near-daily muck removal. “The slurry was just that—liquid, messy and sloppy,” notes Philips. “It was impossible to contain and as a result we were tracking slurry through our yard, and the trucks were tracking it into the streets and into public right of way.”

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The filter press configured to fit into Ready Made’s existing truck washout station. It utilized the existing former settling pits as storage for recycled water, suited to truck washing and washout.

Once the settling pits had been mucked out, Ready Made was paying to have material hauled and disposed of. The vessels tended to leave waste material heavy and laden with water, boosting transportation costs. “We’re within Salt Lake City, so we’re not in an area where we can get rid of waste just by pushing it on the back 40,” Philips affirms. “We’re on a small, paved lot, and part of the agreement with West Valley City was to control and maintain process water on site.”

SOLUTION

On 2014 World of Concrete day one, Philips and his sons noticed a new, innovative piece of equipment: the Concrete Washout System filter press, centerpiece of the McLanahan Corp. booth. After gaining insight on filter press operation and conditions where customers had deployed such a unit, the Ready Made team’s interest was piqued. “We were having an issue with water and contamination, and trying to reuse settle water,” Philips notes, adding that the Concrete Washout System has “a small footprint and we thought it would fit within the area designed for our reclaiming system.”

Through several meetings, he and his sons provided McLanahan sales and engineering staff data on the Salt Lake City plant site and fleet, helping determine the appropriate Concrete Washout System, which features a 15-plate filter press with 630-mm x 630-mm plates that produce a 35-mm thick cake and is designed to handle up to 400 tons of cement fines per day. After sufficient brainstorming with family and McLanahan staff, recalls Philips, “I could really see this being an important piece to our ready mixed puzzle.”

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Prior to the Concrete Washout System filter press installation, Ready Made Concrete built a ramp to serve a two-truck station feeding a reclaimer, capable of capturing coarse aggregate and about 50 percent of fine sand. Slurry was handled with conventional settling pits that consumed valuable yard space, required daily attention, and left much fine aggregate landfill bound—amid cement fine muck.

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A Concrete Washout System with overall footprint of around 15- x 20-ft. was installed adjacent to Ready Made’s existing reclaimer. Operators early on observed a significant amount of sand was escaping the reclaimer and being passed along to the filter press, which is best suited to dewatering cement fines into easily handled, dry cakes, and recovering clear water with low suspended solids. Joined by McLanahan representatives, says Philips, “We investigated, ‘Why are we having problems with the press or the filters?,’ and ultimately discovered that we were losing 50 percent of the sand.”

Based on extensive experience with fine sand processing, McLanahan engineers suggested their Separator, a cyclone fitted with an underflow regulator to improve recovery at the reclaimer and limit filter press-bound material to primarily cement fines and water. “McLanahan engineered the whole process for us. We installed the cyclone and the pumps as designed, and all of a sudden we were recovering 100 percent of our sand,” says Philips.

RESULTS

Recovery of sand has been extremely important: Ready Made can reuse it in most ready mixed orders, while eliminating hauling costs. Admitting limited knowledge of the Separator prior to the order, Philips recalls, “We evaluated and realized we were losing 50 percent of our sand. The Separator was a quick payback once we realized that we could recover material we were just hauling to the landfill.”

Return on the Concrete Washout System investment is easily calculated by the recovered sand alone, he adds. Additional savings and ROI are reflected in reduction of trips to the landfill—to which low-moisture cement fine cakes are dispatched. Indeed, filter press cakes are easy to handle and manager, and a far cry from the slurry Ready Made was used to dealing with. Additionally, the producer has been able to utilize clean, recycled water from the filter press in concrete production and plant operations, especially truck washout. With the need to maintain a small production footprint and closely monitor water consumption, plant team members are also developing new uses for the recycled wash water.

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After Concrete Washout System testing, Ready Made plant staff and McLanahan engineers determined that excess sand in the slurry was limiting the efficiency of the overhead beam filter press and its 630-mm x 630-mm recessed chamber plates. The producer added the McLanahan Separator, a cyclone fitted with an underflow regulator that improves the recovery of sand from the washout water before transferring cement fines and water to the filter press. The Separator equips the filter press to live up to its potential for rapid conversion of slurry to recyclable water and cakes of primarily cement fines composition. McLanahan has calibrated the filter press to operate at 80–100 psi and yield 35-mm thick cakes.

“We are grateful we hooked up with a worldwide company willing to send a crew of three or four out to our little operation in Salt Lake City,” Philips notes. “Every time there’s been an issue, McLanahan people have been here to help us and work through it.” — McLanahan Corp., Hollidaysburg, Pa., 814/695-9807; www.mclanahan.com