Earlier this month, the European Commission unveiled its revised circular economy (CE) package, which saw a 65% recycling target set for municipal waste by 2030, lower than the 70% originally proposed in the 2014 package.
Although this revised target is bound to attract criticism from many for being less ambitious, rather than squabbling over percentages we should instead be focusing on how best to get there.
First we need to address the current situation in the UK where, rather than being recovered, vast amounts of valuable and recyclable residual municipal solid waste (MSW) is being thermally treated, exported as refuse-derived fuel (RDF) or sent to landfill.
Energy recovery plays an important role in the UK’s waste management infrastructure, but our efforts should be concentrated on material recovery for recycling first, with only the remaining untreatable residual waste used in energy production.
If we are to increase the UK’s recycling rate significantly, we need to invest in new recycling facilities and also make existing facilities, many of which are now 10-15 years old, more efficient. Strong markets do exist for many of the materials found in MSW – mixed plastics, PET/HDPE/PP, mixed paper, cardboard, film and metals – but we should be looking to expand existing markets and develop new markets for the recovered material.
The CE package will put greater emphasis on the use of recycled materials in the production of new goods, which will help to strengthen further the commercial and environmental arguments for recovery from MSW.
The 65% recycling target for 2030, coupled with the CE’s emphasis on using more recycled materials, presents MRF operators with an appealing commercial opportunity, but it is not a simple case of throwing money at new or existing MRFs.
Plant design is a complex process and, with operators under pressure to increase capacity and throughput, reduce manpower, keep operating costs down and maximise profits, it makes sense for them to seek guidance from industry experts to ensure MRFs are designed for maximum efficiency.
Tomra Sorting is working with a number of UK waste management companies which are designing their plants to achieve maximum recovery and purity rates from MSW using sensorbased sorting technology.
The scope to recover and treat MSW using traditional recycling processes is limited so, by taking advantage of the latest sensor technology, recycling companies are able to achieve high recovery and purity rates of recoverable materials. Typically, it is possible to achieve 60-70% recovery rates on MSW infeed material.
To ensure optimal recovery from MSW, all infeed material arriving at the MRF should initially be pre-shredded to roughly 250mm. A bag opening device can be used. Then, screening and sizing should take place to separate materials before sensor-based sorting.
One of the biggest challenges when treating MSW is the high content of organic material, which can significantly affect the quality of the recyclables output. Most organic matter is in the ‘70mm or less’ fraction, which should be targeted and eliminated early on.
The plastics from fines can be recovered using near infra-red (NIR) and inerts separated from the organics using X-ray technology. The glass can be recovered from the inert using lasers. Recovered inert material can then be used for construction applications, while any organic material left at the end of this process is ready to be treated using a biological process such as anaerobic digestion.
The next stage involves a unique approach that splits the remaining 70-250mm materials into two lines: one for 2D light and another for 3D heavy. These concentrations can then be processed through a combination of NIR optical sorting to yield high-quality, high-value end products including film, paper, mixed plastics, PET and PE. An RDF fraction is also captured.
An efficient MRF design using bespoke technology will not only deliver maximum possible throughput, but also ensure the best possible material quality, the highest material recovery and the lowest possible labour costs.
With the 65% recycling target now proposed for 2030, increased recovery from MSW could play a vital role in helping the UK to reach closer to this expected target.
Steve Almond is sales engineer at Tomra Sorting Recycling