Terex Washing Systems is expanding into the Australian market with a flexible plant design and closed loop ethos.
Construction and demolition (C&D) waste accounts for 30 per cent of all waste generated in the European Union, according to the European Commission’s Environment Department.
This level of waste generation creates a significant opportunity for recycling, which is where Terex Washing Systems (TWS) comes in. The global business, based in Dungannon, Northern Ireland, was established in 2012 in response to a growing demand for recycled aggregates.
Oliver Donnelly, TWS Business Line Director, says the confluence of recycled aggregate demand and C&D waste levels creates a significant space for market expansion.
“Exhaustion of natural sand and aggregate reserves, and increased legislation around accessing new reserves, means there is a widening gap developing in the market,” Oliver says.
While 10 years ago companies certainly had the option of recycling C&D waste, Oliver says those options were limited to crushing and screening.
“Customers are starting to realise there’s potential to create higher specification aggregate when they use a wet processing system,” Oliver says.
TWS offers this type of processing system, allowing customers to individually tailor plant designs to specific requirements.
According to Oliver, when processed in a TWS plant, C&D waste can triple in value.
“There’s also a strong economic and practical argument for reusing C&D waste as it’s very expensive to transport. When a construction company has access to a washing plant, they’re able to equalise that cost,” Oliver says.
Oliver says that while the bulk of TWS’s business is based in the UK and Western Europe, he has recently noticed an uptick in interest from the Australian market.
“A lot of enquiries from Australia require applications similar to those requested by J Mould, a recent customer in Reading, just outside London,” Oliver says.
“This is due to shared concerns around land availability and water access in metropolitan areas.”
James Murphy, TWS Australia Regional Sales Manager, says the Reading facility is a flexible plant capable of processing material in excess of 200 tonnes per hour.
“Processors working with C&D waste will be aware that what comes through the gate is rarely consistent,” James says.
“They need to be prepared to handle the most challenging, highly contaminated material to ensure a consistent, high quality end product.”
For J Mould’s site in Reading, TWS incorporated an AggreScalp feed system. The two-bearing, 3.6-metre-by-1.5-metre two-deck screen separates any 80-millimetre oversize material and conditions the remaining feed material prior to the wash plant.
“Minus 80-millimetre material is conveyed to a six-metre-by-1.8-metre inclined pre-screen. This two-deck rinsing screen separates sand and fine particles from the aggregates before they are scrubbed in the PowerScrub 200 log washer system,” James says. 
“Twin counter rotating axles intensively mix the material, breaking down conglomerated clay balls and removing deleterious substances from the surface of the aggregate.”
According to James, the aggregates are then rinsed clean on a linear motion sizing screen.
“Any fine sand and silt that has been liberated in the log washer is rinsed through to the sump tank, leaving the aggregate clean and free of contaminants,” James says.
The plant also includes a prewash system for the dedicated
two-stage cleaning of zero- to five-millimetre sand.
James says the prewash system’s large 3.6-metre diameter conical sump tank allows for gentle clay float off.
“A HK200 separator, traditionally known as a dewatering cyclone, allows for effective sand cleaning even with a varying feed to the plant,” James says.
“Its vacuum bleed allows for real-time adjustments, meaning a consistent, optimum underflow density is at the operator’s fingertips.”
According to James, operators often don’t know how dirty the sand is. The prewash system therefore functions as a safety measure for the customer.
“They can consistently produce a high-grade sand product no matter what material they’re presented with,” James says.
“We want companies to reuse their waste and put it back into market. There is a strong economic, practical and environmental argument for the continued and expanded use of sustainable aggregates.”
James says all process water from the washing system is filtered through a TWS Aquaclear water management system.
“An automated Flocculant dosing system treats the process water as it enters a 20-metre diameter rake thickener,” James says.
“Thickened sludge is extracted from the base of the rake thickener and stored prior to further dewatering in the TWS Aquaclear filter press. The silt and clays contaminants are reduced in volume through dewatering, with the potential to be reused in landfill capping.”
According to James, the system recovers 95 per cent of the process water required to produce the clean aggregates and sand, effectively closing the loop.
“TWS has focused on developing a comprehensive portfolio of water management products so companies can operate on a small footprint, in close proximity to the major sources of C&D waste – large cities,” James says.
TWS manage the Australian market through Terex Jaques, a manufacturer in Dandenong, Victoria.
“Terex Jaques has expert teams of applications, electrical and service engineers located at each of our regional bases in Melbourne, Sydney, Brisbane and Perth. Each service base also carries a large consignment of spare parts,” James says.