UK-based AAL Recycling (AAL) began trading more than 30 years ago as a one-man, one-truck, one-excavator company. It is now one of the largest demolition, hauling, recycling and excavation companies in Jersey and the Channel Islands, employing more than 85 people and with a fleet of more than 70 vehicles.
Currently, AAL operates the island’s commercial and household construction waste-recycling centre in La Collette, supporting the island’s sustainability project in every way possible. The demolition and excavation area has had the company’s fastest growth, thanks to managing some of the most complex projects developed on the island in recent times. Given the great growth of AAL Recycling (AAL), its owner and CEO, Alan Langlois, approached Matec Industries (Matec) to find innovative and technological solutions that would allow processing up to 150t/h of recycled material, with water consumption of less than 25m³/h.
The plant would have to comply with all current regulations, ensuring low energy consumption, and maintaining a high washing and sorting performance of the processed material.
To ensure that more than 95% of water used during washing and sand sorting was recycled, a complete wastewater treatment and filtration plant was installed by Matec for AAL. From the collection tank, turbid water is pumped into the decanter through the stainless-steel piping via the use of a centrifugal pump. The flocculating polyelectrolyte solution is injected into the feed line of the settler and reacts with the suspended solids in the liquid, speeding up the natural sedimentation of the mud particles.
The turbid waters arrive in the vertical decanter where the reaction of the polyelectrolyte takes place, aggregating the sludge particles and causing them to precipitate. The clarified waters, free of suspended solids, then rise to the top of the decanter and by weir and are collected in the perimeter channel located at the top of the decanter. They are then conveyed to a stainless-steel clean water tank. At this point they are ready to be reused in the production cycle again through the clean water relaunch pump.
The sludge, meanwhile, settles inside the cone and is discharged once it reaches the required consistency by the opening of the automatic valve. It is sent to the homogeniser tank below where it is kept in slow agitation. At this point it is ready to be fed into the filter press. The Matec filter press is an industrial machine designed to achieve the best results in dewatering industrial or civil fluids (often referred to as sludge).
Matec filter presses are designed for use with High Pressure Technology (HPT), capable of working at both operating pressures common to all filter presses and at higher pressures.
The wastewater treatment and filter press module consist of a 1500×1500 filter press with 170 TT plates; a BIFANG 100,000litre sludge homogenisation tank; a 220,000litre static vertical decanter; a 6,000litre/minute clean water pump; two clean water tanks (10,000litre and 40,000litre capacities, respectively); a BIFLOC automatic flocculant management system; a 6,000litre/minute centrifugal pump for loading vertical decanter; and a 50,000litre dirty water tank.
An AGGRETEC 150 semi-mobile screening and washing unit, and a SCRUBTEC LW-080-500 heavy scrubbing unit were chosen for washing, grading and drying AAL’s product range. AGGRETEC is Matec’s rapid installation modular washing and sorting plant ideal for a wide range of sectors, including aggregates, recycling, reclamation and mining. Being a semi-mobile system, it is easily transportable making it ideal for working on construction and demolition sites. The solution for AAL consists of three conveyor belts (for 0-2mm, 2-4mm, 25-40mm product); a sand recovery unit with hydrocyclones; three-deck vibrating screens; a magnetic belt separator; a feeder screen; and a loading hopper.
The SCRUBTEC LW-080-500’s combination of an intense cleaning action and its removal of light contaminants are said to make it a key component in construction and demolition waste-recycling systems. It is also ideal for aggregates and mined materials with high clay content.
The material is rubbed through inclined paddles arranged in series inside the machine. These paddles slow down the material feed when it is very dirty but ease the feed when it is cleaner. The entire washer is coated with an interchangeable wear-resistant steel armour.
The SCRUBTEC LW-080-500 comprises a log wash, impurity screen, a dryer/finishing screen, three conveyor belts (16-25mm, 10-16mm, 4-10mm product), and a pre-screening solution.
Skipway recently opened its doors to its latest trommel fines wash plant to demonstrate how CDE wet processing technology is supporting the Northern Ireland-based waste-management firm to divert over 95% of its trommel fines from landfill. The 16-17th November showcase began with a guided tour of CDE’s world-class manufacturing facility in Monkstown, County Antrim, Northern Ireland.
Guests saw the 300,000 sq. ft. facility in operation, where CDE’s advanced wet processing solutions are commissioned for customers around the world, from Creagh Concrete in Toome, Northern Ireland, to Posillico Materials LLC on Long Island, New York; Repurpose It in Melbourne, Australia, to Feiring Bruk, Norway.
As part of a long-term investment strategy in its manufacturing capabilities, CDE recently commissioned two new Bystronic high-speed sheet-metal laster-cutting systems. The systems integrate with a new 400-tonne steel storage and management system incorporating fully automated loading and offloading of the laser cutters.
Following the tour of CDE’s facility, guests were invited to tour its latest trommel fines solution, designed and engineered for Skipway.
The new 50tph trommel fines plant, the first in Northern Ireland, has been commissioned at the waste-management firm’s processing site in Dunmurry, near Lisburn, and is one of of three recycling facilities it operates (the other two are in Belfast and Portadown). The CDE solution for Skipway incorporates an AggMax modular logwasher, EvoWash sand wash plant with Counter Flow Classification Unit (CCFU), AquaCycle thickener and static screens.
The state-of-the-art plant diverts trommel fines from landfill and converts the material into a resource by producing recycled products with the same specification and quality as quarry-grade sand, therefore making it suitable for concrete and building products while also improving the quality of other recycled aggregates such as pipe bedding and recycled hardcore.
Skipway director Trevor Heatrick said: “By putting trommel fines through a wet processing plant, the clean sand and aggregates recovered can be resold and reused in the secondary aggregates market. This minimises disposal costs, as well as closing the loop on challenging waste streams to create a more circular economy and generating additional revenue for our business.”
Mansfield Sand Company Limited has been quarrying sand in Nottinghamshire, England, for more than 170 years. It is known countrywide as a supplier of materials for top-class sports and sporting venues across the UK and Ireland. It supplies sand material to 16 Premier League clubs, 16 Championship clubs and 120 other football league and non-league clubs for use in their stadia and training ground facilities.
Besides sand for football stadiums, Mansfield Sand also produces a wide range of products for landscaping and equestrian uses, including championship golf and world-class show-jumping arenas, as well as asphalt sand, foundry sand, and sand for concrete and brick products.
In 2014, Mansfield Sand wanted to upgrade its plant and control system to process a new deposit. It required a plant that would process 300tph of -65mm sand to manufacture their various products, including golf sand that meets United States Golf Association standards, block pavior sand and asphalt sand.
In addition to this requirement, the local planning commission also set a noise restriction in place so the new plant would not disturb some rare birds nesting near the boundaries of the site. It was at this time that Neill Rowland, McLanahan applications engineer, knocked on their door. He explained that McLanahan could offer them a Hydrosizer sand plant that would produce five different products in one pass.
“One of the things that sold the plant was McLanahan’s technical ability to offer this,” said Rowland, noting that experience and confidence also played a role in Mansfield Sand’s decision to work with McLanahan.
Mansfield Sand was familiar with Hydrosizer systems from an existing plant they had been operating for several decades, so they had already realised the benefits of Hydrosizers for what they were trying to achieve.
“When you start getting down to really fine sizing, Hydrosizer classification is really more efficient and more cost-effective,” explained Rowland. “The Hydrosizer is the only piece of equipment suitable for the application to achieve the tight tolerances.”
McLanahan installed a Hydrosizer plant incorporating McLanahan Pumps, Sumps, Hydrocyclones, Separator, Dewatering Screens and Blending System with the ability of blending to 1% accuracy to help Mansfield Sand meet the strict specifications required of their final products. The final products are discharged at less than 15% moisture, which creates stockpiling efficiency and allows for further drying processes.
To meet the requirements set forth by the planning commission, the entire plant is housed within a galvanized structure, clad and insulated to reduce the noise level. The plant’s components are also lined with rubber to protect them from the abrasiveness of the sand. After some calculations from Mansfield Sand’s laboratory technicians, the company discovered the waste from the wash plant would fill their lagoon within 18 months, so it turned to McLanahan for help with its water management.
McLanahan provided an Ultra Fines Recovery System to recover fines down to 40 microns to extend the life of Mansfield Sand’s lagoon system.
“Anything bigger than 40 microns is recovered,” Rowland said. “Anything less is going to the lagoon.”
Since commissioning the Hydrosizer plant, Mansfield Sand Company has not received a single customer complaint due to the performance of the equipment. The plant’s modern control system gives Mansfield Sand the ability to adjust the product to meet consumer demands.
“The plant does have quite a bit of functionality for them to develop product and potentially react to market changes,” explained Rowland.
In four years of operation, the Hydrosizer plant has proven to be both stable and reliable. It produces a consistent 280tph, and to date, the plant has produced 2 million tons of sand for Mansfield Sand Company. Furthermore, the Ultra Fines Recovery system has doubled the life of its lagoon by allowing Mansfield Sand to capture the fine material.
“It’s a low-value product, but it’s a product they can sell, and it’s a product that isn’t filling their lagoon, which is the real benefit to them,” Rowland said.
Overall, Mansfield Sand is pleased with the Hydrosizer plant and Ultra Fines Recovery System.
“A good team effort by both parties and a professional working relationship providing a technologically advanced plant gives Mansfield Sand flexibility, controllability and future-proofing for the estimated 30-year life of the site,” said Richard Abraham, managing director of Mansfield Sand. “Now, four years on, we continue to have a fantastic working relationship together. Our process plant continues to manufacture our premium quality sands to Mansfield Sand’s exacting standards.
The partnership between Mansfield Sand and McLanahan has rested on the McLanahan team’s awareness of the importance we place on the reputation of our products and our respect for their experience. The partnership had a lot to prove, and it proved to be a great success.”
Terex Washing Systems was at bauma 2022 in Munich, Germany, where it staged a live demonstration of its AggWash 60-1 washing and recycling plant, capable of producing up to four high-quality aggregate and up to two sand products at up to 70t/h.
An innovative plant that integrates heavy attrition with sizing, lightweight contaminants removal and hydrocyclone-based fines recovery in a single highly portable chassis, AggWash is a rapid-install solution for a wide range of applications within the aggregates, recycling, remediation and mining sectors.
The AggWash 60-1 has a modular design and comes pre-plumbed with a single connection point for quick set-up. The machine’s log-washer angle adjustment allows increased material retention and removal of trash, while the overband magnet on its feed conveyor removes ferrous metals. The AggWash 60-1’s rubber-lined pumps, cyclones and transfer points are also said to extend the plant’s life.
