LAWR

14 Local Authority Waste & Recycling April 2015 am often asked "how would you design the perfect commingled MRF?" Although I would argue that there's no such thing as a 'perfect' MRF, there are many factors that will contribute to its success. So, let's look at how we, as technology specialists, would approach the design of a brand new commingled MRF. The old adage "failing to plan is planning to fail" certainly applies when it comes to MRF design. Planning, understanding and collaboration between all parties involved in the design process are key. By getting together with their plant builder and technology providers before design starts, operators can significantly reduce the risks associated with the build and long-term performance of the plant. To use another well-known saying, "knowledge is king". Operators need a detailed understanding of the infeed material's composition and of the end markets for recovered material. A waste characterisation study is key in understanding the percentage, sizes, density and variability of the in-feed material. Similarly, a detailed knowledge of the end markets for the products and residue – outlets, specification and prices – is also vital to inform operators which material is worth recovering. I Material recovery facilities (MRFs) are an essential part of the recycling process. In order to process high quality outputs they need to be designed in an efficient way. Here, TOMRA Sorting Recycling's Steve Almond gives his advice on what elements are needed to design a 'perfect MRF'. Designing the perfect commingled MRF MAPPING THE MRF Steve Almond is sales engineer at TOMRA Sorting Recycling MRF's footprint Another important consideration is the MRF's footprint. We often find that operators underestimate the amount of space required. Storage of the raw in- feed material, space for the equipment to process the material and storage of the end-baled product all need to be taken into account. When it comes to the use of technology in our 'perfect MRF', there are two main stages to consider: the upfront mechanical treatment and then the use of automated technology. In order to ensure the optimal efficiency of near infrared (NIR) sorting technology, some basic mechanical treatment needs to be done regardless of the volumes of waste. All infeed material should be screened to separate out the contamination to find fines (contamination) of 50mm or below. The light 2D material must be separated from the heavy and 3D items. The material needs to be sized to ensure the newspaper and OCC (old corrugated containers) are separated from the mixed paper. By following this process correctly upfront, the product is in the best condition to then be further sorted using optical sorting technology and ultimately achieve the highest recovery and purity rates possible. Dust control Consideration must also be given to the quality of compressed air and dust control. With the right grade and qual- ity of air and effective dust control, the NIR units can see what they are meant to be doing better without too much dust in the air. Often these steps are not always followed correctly or to the right level which will impact on the performance of the NIR technology. However, if all of the recommendations I've highlighted are followed, operators are then ideally placed to use the very latest in automated technology to produce high-value-saleable material and achieve recovery and purity levels that are simply unachievable using manual labour. Today's NIR technology is capable of purifying the >200mm line by separating the cardboard or OCC and plastic films, effectively producing three products – news and PAMs, OCC and films. NIR technology can also be used to recover and separate all the rigid plastics by material size and colour as required by the markets. The mixed paper can also be recovered. To sum up, although the 'perfect' MRF probably doesn't exist, at our firm we've come across a few operators have taken the approach we've discussed and are achieving industry-leading results. Others in the industry should now be looking to learn from the best. TOMRA's Steve Almond " Failing to plan is planning to fail "

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