Waste Management In Action

Concrete jungle: Lincom Group

Lincom Group’s Concrete Washout Reclaim plant is allowing recyclers to recover sand, water and aggregates for reuse while reducing waste storage areas and handling costs. 

Recovering sand, water and aggregates for beneficial reuse and minimising waste storage and handling costs have been on the agenda of Lincom Group over the past year.

The materials processing equipment specialist recently created a new division – environment and process – to go beyond its capabilities and establish a strong position in the water filtration and water management sector.

Pete Godwin, previously an independent filtration and dewatering consultant, was brought on full-time to lead Lincom’s new environment and process division as manager. Pete says that developing a product with Lincom allows it to service a greater proportion of the market.

“We’re doing something very separate and distinct from the normal sand and aggregates business. The solutions our new division offers are appropriate not just for sand and aggregates, but we’re now servicing a much wider market in food, wastewater treatment, tailings, minerals and a variety of other areas,” Pete explains.

After extensive research and testing, the company developed its concrete washout reclaim system – a Rapid Reclaimer and OFS filter press. The winningcombination allows concrete recyclers to capture clean sand, aggregates and water for further reuse.

Lincom Group recently put on a demonstration day at the Firth Concrete yard in February in Auckland – the largest national manufacturer of ready mixed concrete.

The well attended demonstration allowed attendees to gain a close-up glimpse of the Lincom concrete washout reclaim system.

Pete says feedback from customers was highly positive with a significant number of New Zealand and Australian customers impressed with its capabilities. He says customers were particularly drawn to the high quality of water.

Notably, Pete says the system reduces the footprint for concrete reclaim significantly.

“The reclaimer was around 30 years ago and the world seemed to lost interest for a time, but right now it’s on the top of everyone’s list,” Pete says.

“The prices of real estate in New Zealand and Sydney are a big driver for this because they can get more work out of a much smaller yard by having just a filter press and a reclaimer.

“If it costs one or two million for a block of land in Auckland, you can take a third of that off because of more efficient use of space.”

The Germany-designed and manufactured OFS recessed chamber filter press uses a proved solid/liquid separation technology. Unlike a traditional settling pond system with its large footprint, the filter press is a much more compact solution where the dirty water is pumped from the agitated storage pond, through the press, then back into a clean water pit.

“The rain that falls from the sky ends up going through the same process so it’s a big general clean-up of the area. Concrete plants spend all day hosing due to the dust created and they use large quantities of water to allay the dust,” Pete explains.

“We’ve reduced the dust from breaking up dry waste concrete. If you can reclaim the concrete at its wet stage there is no dust generated, so environmentally that’s a good thing.”

Pete says that concrete plants used to have large settling ponds that would take up excessive amounts of space with cement and stone settling to the bottom. After a week, they would pump out the water and recover sand and aggregates that emerged as a waste product.

He says the reclaimer has a better washing capability than other competitors and places solids into two distinct piles. Other machines may use one pile.

“When the aggregates come out, they are clean. If I pick up a handful of aggregate, there is no colour on my hand – it’s just clean water.”

The rapid concrete washout reclaim unit takes the waste concrete and deconstructs it back into base sand and aggregate components.

The OFS filter system recovers grey water by filtering and compressing dewatered cement fines into manageable “cake” form, solving a variety of issues for concrete producers.

The rapid reclaimer is capable of processing up to 20 cubic metres of concrete slurry per hour.

The reclaimer discharges the cementitious water into the dirty water pit where it’ss continually stirred to keep the spent cement fine particles in suspension. The clean water, known as filtrate, is captured and returned to a clean water pit for use in further concrete batches and reuse in the reclaimer’s washing and separation process.

Sand and aggregates are separated within the reclaimer, with the dewatered sand conveyed by twin hydraulic screws to one pile, while the washed aggregates exit via a belt conveyor to another separate pile. The cementitious water overflows the adjustable weirs and is piped via gravity to an agitated storage pond.

At the end of the cycle, filter cakes fall into the void below the filter press where they are removed as waste or for beneficial reuse.

In tailings and water management, Pete also predicts that centrifuges will continue to garner additional interest in waste and recycling applications into the future, as they are traditionally being used by many major water authorities at this time.

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