With the installation of optical sorting equipment, a recent MRF upgrade from Wastech Engineering saw capture rates increase by 30 per cent.
Wastech Engineering’s Scott Foulds highlights the latest technologies to support a variety of materials recovery facilities.
When Freshkills Landfill in Staten Island, New York, one of the largest landfills in the world, closed at the end of 2001, it forced the City of New York to explore alternative waste management options.
One option mooted in the early 2000s to fill the gap was a materials recovery facility (MRF). According to a research paper published by the Department of Earth and Environmental Engineering, a 150-ton-per-hour facility could handle all of New York City’s recyclables. The operations within the MRF were proposed to be as automated as possible, increasing speed of operation, reducing costs and improving material recovery.
More than a decade on, New York City and other cities across the globe have embraced best practice, with the next generation of screens, optical sorters and air separation technology providing an end-to-end solution.
In leveraging more than 25 years’ experience supplying waste and recycling equipment, Wastech Engineering has been offering technologies to allow MRFs to sort and separate a wide range of waste streams.
Wastech’s commingled recycling screen range features the latest in design and engineering from their US partner The CP Group. From the proprietary cam-disc style CP Screen (polishing screen) to the OCC Screen and Auger Screens, the CP Group continues to set the pace for screening technology in kerbside recycling.
Scott Foulds, Operations Manager at Wastech, says the company’s range of screens provide full flexibility in MRF design for sorting and separating of various commodities.
“The flexibility of the MRF design, including which streams are captured, is ultimately designed around the outputs the customer wants for the markets they will sell into,” Scott explains.
“The CP Group in the US has implemented an extensive research and development program over the past 10 years to develop their screens to minimise wrapping and increase efficiency in seperation.”
Scott says the OCC Screen is an essential machine for any MRF. The screen effectively separates old corrugated cardboard (OCC) from other mixed fibre, containers and debris. Characterised by its low maintenance and wrapping design, the screen drops all material under 300 millimetres through the screen for further sorting.
“99 per cent of what goes over the OCC Screen will be clean cardboard with a very high purity rate so you don’t need quality control,” Scott says.
He says the steel discs and shafts have been designed for reduced wrapping, with a lifespan of around 15-plus years due to their robust construction and quality design.
The glass breaker screen is the next step in the process which breaks and separates glass and fines down to a 50-millimetre-minus product. The glass is removed early in the sorting process to protect the longevity of the equipment upstream.
Air separation technology can then remove light materials from glass such as small fibre, organics and plastics, with Wastech offering a host of systems through The CP Group or Impact Air.
The NewScreen is ideal for MRFs processing higher volumes that want to capture old newsprint. It is designed to automatically separate large fibre from mixed paper, containers and debris.
“If you’re operating a smaller MRF, then the CP Screen could recover all the fibre. But it does come down to what markets the customer has to sell their products into. If they’ve got a market for mixed paper, newsprint and cardboard, it’s better to separate those items, especially if the end user is getting good value for money,” Scott explains.
The CP Screen ensures a clean stream of paper by eliminating residues such as small fibres and organic material by dropping this out through the screen. The paper (2D material) goes over the top of the screen and the containers (3D material) go off the back of the screen. The CP rubber disc screens can be adjusted for speed and inclination, allowing it to be varied from 30 to 40 degrees, which help improve the efficiency and quality of the screen’s functionality.
Scott says the CP Screen has numerous advantages over other separators, namely the quantity of throughput and quality of separation.
In continuing to expand its offering to Australian MRF operators, Wastech launched the CP Auger Screen in 2018 – which enables accurate separation of newsprint and large fibres from the material stream early in the separation process. This is particularly useful in higher volume MRFs.
While robotics is largely an emerging technology, Scott says a variety of optical sorters can be used instead to sort fibre and containers and achieve high throughput, capture rates and quality outputs.
“As an alternative to robotics, we’ve come up with a different design in our optical sorting range where we use a single line optical sorter on the container line.
“All the containers pass through an optical sorting head which determines the container type, whether it be aluminium, PET, HDPE or liquid paperboard.”
The container is then ejected into the designated hopper as it passes down the conveyor line. Scott says all of Wastech’s products are backed up by its 24-hour Service Centre, with 15 service vehicles on the road nationally.