Mixed waste challenge

Mixed waste challenge

ELB Equipment is offering a solution to remove contaminants from municipal solid waste for composting following the EPA NSW’s recent announcement on mixed waste organics.  

In late October, the NSW EPA announced it would stop the restricted use of mixed waste organic material on agricultural land. 

According to a statement by the then NSW EPA Acting Chair and CEO Anissa Levy, the restricted use of the mixed waste organic material had been permitted on the basis that it provided beneficial reuse of waste. She said extensive independent research commissioned by the EPA found that it no longer passed that test, with limited agricultural benefits and a potential risk to the environment from contaminants such as plastic and glass. 

The announcement also revealed the EPA would cease its use on plantation forests and mining rehabilitation land until further controls can be considered. As a result of its decision, the EPA revoked the Resource Recovery Exemption and Order.  

As the organics recycling industry responds to the decision, technology supplier ELB Equipment has been liaising with its clients to provide them with a timely solution.

Christopher Malan, Managing Director of ELB Equipment, says the key customer base affected by the decision are those dealing with red bin waste. 

“Because the applications for it are already, by nature, limited due to the lack of source separation and potential contamination that exists, mine site rehabilitation in particular was an attractive method for disposal of this material as the sensitivity to the product was generally lower,” he explains. 

Christopher says the concerns surrounding the revocation were borne out of small particle contaminants such as metal, glass and plastic – noting that Europe leads the way with its landfill redirection and recycling, in spite of a compost standard that places exacting screening measurements and cleaning requirements on small particles. 

Furthermore, by December 2023, all EU member states will be required to implement separate biodegradable waste collection, according to draft legislation. At the same time, he concedes their source separation is generally superior. 

Christopher says that one of the challenges is that it becomes harder and harder to remove particles from the waste stream as they become smaller.

To help processors meet the ongoing challenges of quality compost, ELB has continued to supply the latest in technology from Komptech – a technology developer of mechanical shredding, composting, screening and separation products. 

“Europe has had more and more exacting standards for processors to meet and as they’ve gone along, technology providers such as Komptech have stepped up to that challenge and provided newer and more innovative technologies to deal with the issues,” Christopher says. 

Komptech’s latest technology is a mobile densimetric table which has the ability to screen out glass, plastics and metals between two and 10 millimetres in diameter which meets the existing European regulations. 

The technology is suitable for municipal solid waste and any processors dealing with contamination issues, especially glass. 

Christopher says the company received significant interest from its customers regarding the product since the EPA announcement. While units have yet to be released by ELB in Australia, the machines have been used in Europe extensively.

He stresses the challenges of extracting small particles, noting that the Komptech technology is no silver bullet and requires a holistic approach to solving the problem. “If you start at the beginning with a view that at the back end of this, the densimetric table is going to be doing its work, to try and remove the particles, you can make it work,” he says. 

Craig Cosgrove, Komptech Sales Manager, says the machine is a proven solution for handling materials with contaminants over two millimetres, with pre-screening critical to reducing volumes and drying ensuring the product doesn’t bind up in the machine. 

Prior to entering the densimetric table, the material goes through a number of clarifying stages to remove larger contaminants, including a preliminary composting process to dry the material to ensure moisture does not exceed 30 per cent. 

Once the material arrives to the machine, it is pre-screened to a size of 10 to 15 millimetres via drum or star screening. The resulting fines are screened for contraries with one or more air separator tables. 

The tables are tilted vibration plates with two-millimetre apertures so that anything smaller can fall through the screens. An air current is passed upward through the screens and out through fans, extracting the plastic, films and lighter materials. The stream then passes through a cyclone which removes dust and fine particle organic matter, allowing the plastic to continue onto bins where it’s collected. As the tables vibrate, they are also on an angle so that the lighter material rolls up the screens in one direction, while the glass and other inert materials tend to roll down in the other direction.

Craig says the total throughput is 12 tonnes per hour, which is why a total solution is important.

Once the process is complete, material fines that passed through the screening and cyclonic filters are reunited with the organic material, resulting in a clean organic process to return to the composting process. Contaminants such as sand can be further recycled, with any remaining residuals going to landfill. 

Christopher says ELB Equipment views its relationships with its customers as important partnerships. With eight branches across Australia and New Zealand, the company is on hand to provide ongoing support to its customers with service technicians and parts on shelf. 

In spite of any challenges ahead in NSW, Christopher notes the problem is surmountable with the right partnerships, including with the EPA, technology providers and the community.

“We would encourage anybody out there with concerns about this decision or would like some advice on how they can modify their process to better comply with EPA regulations or give them some other avenues for disposal to call us and we can discuss options and provide case studies on what’s being done overseas,” he says.

This article was published in the December issue of Waste Management Review.