There are many factors that combine to help ensure a successful MRF upgrade. Planning, understanding and collaboration between all parties involved in the upgrade process are key.
By working closely with their chosen plant builder and technology providers before starting the upgrade work, operators can significantly reduce the risks associated with the plant’s long-term performance.
Automation is a fundamental component of a successful MRF upgrade. There has been significant progress in automation since many MRFs were first built more than a decade ago, both in terms of throughput and material recovery. Automation can vastly reduce labour requirements, increase recovery and quality of materials, deliver consistent plant performance and recover certain materials that the human eye cannot easily identify.
But to fully benefit from automation and optimise recovery of target materials, it is essential for MRF operators to optimise the upstream plant design.
Integration is key and the plant should be considered as a whole, so operators need to understand their production objectives and be involved in the design and build process.
Before starting an upgrade project, MRF operators should undertake a waste characterisation study to understand the percentage, sizes, density and variability of the infeed material.
Equally as important is an in-depth knowledge of the end markets for the products and residue: outlets, specification and prices. Often this will have changed significantly since the MRF was designed and built; the need for higher quality sorting with less waste making its way to landfill is now a significant driver when designing and installing an MRF refurbishment.
Regardless of waste volumes, some basic mechanical treatment will be required to ensure the optimal efficiency of near-infrared (NIR) sorting technology.
All infeed material should be screened to separate out the contamination to find fines of 50mm or below. The light 2D material must be separated from the heavy and 3D items. The material then needs to be sized to ensure the newspaper and old corrugated containers (OCC) are separated from the mixed paper.
By following this process upfront, the product is in the best condition to be further sorted using optical technology and, ultimately, achieve the highest recovery and purity rates possible.
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 & pams, OCC and films. NIR technology can also be used to recover and separate rigid plastics by material and colour as required by customers. The mixed paper can also be recovered.
An MRF upgrade is a significant undertaking, but one that presents operators with an opportunity to take full advantage of the latest that sensor-based sorting technology has to offer. And with automated sorting technology developing so quickly, even MRFs that are just a few years old could still benefit from the introduction of the latest technology.
Steve Almond, sales engineer at Tomra Sorting
Before you start: key considerations for an MRF upgrade
- Ensure you are already maximising performance of your existing MRF before you begin any upgrade work
- Understanding your infeed material in-depth is vital
- Understand your end markets and their specific requirements
- Do not underestimate the amount of space required: include storage of raw in-feed material, space for processing equipment and storage space for the end baled product
- Do your sums: look very carefully at the finances and your business plan
- Do not underestimate how much time it will take for the upgrade: a period of shutdown will be essential
- Bring in the experts: collaboration is key to an effective upgrade