Andrea Lockerbie from MRW magazine discusses our container materials recycling facility with Angus Hamilton, Managing Director, The facility is designed to help Local Authorities maximise the capture of high quality resources from household waste streams.

In 2015 the Scottish Government introduced the Household Recycling Charter with the associated code of practice, this was born out of concerns raised about the number of different collection systems in different local authority areas and the quality of recyclate which were collected and could subsequently be recovered.  With concerns over contamination, the aim was to introduce consistency into the market, reduce confusion with householders and capture high quality recyclates.   Local Authorities were asked to commit to aligning their collection systems to that under the charter, one of the main themes is a move away from fully co-mingled dry recyclate collections to a dual stream approach where fibres are collected separately from containers.

We wanted to be able to help our customers deliver their commitment by offering an option for dry recyclates that promises to recover glass, metals and plastics that are of a consistently high quality. Our new Container Materials Recycling Facility has a throughput of 13 tonnes per hour with an annual capacity of approximately 50,000 tonnes, it officially started operations on the 12th of March and will recover clean separated streams of glass, metals and plastics for supply to re-processors.

Designing the Facility   

The plant has been designed to efficiently sort mixed household containers. Having a very clear understanding of our customers’ needs was a critical part of designing a facility that could accommodate them. The charter envisages glass being collected separately, however for logistical reasons, a number of local authorities in Scotland include glass in the mix of metal and plastics.

Taking this into consideration we began by laying out the system requirements. We were aware that some material would be collected in plastic bags, therefore to have a consistent feed into the plant, we required a suitable bag splitter and feed system.

As this was a new collection system for householders we were also aware there may be a high level of non-target material making its way in to the waste stream. We chose to have a pre-sort cabin immediately after the initial in feed, where these items as well as plastic film from the bags could be removed.

From here the waste passes under an electro magnet to recover steel prior to entering the Machinex three stage glass screen which processes the glass into 50mm cullet and separates it out. Following this, the materials move over a two-metre wide eddy current to separate the aluminium and non-ferrous from the plastics, both streams are then further processed through the quality control cabin, to remove any non-target material that may have been missed in the pre-sort.  There is scope for further separation of Tetra-Pak if required.

The facility also houses a Machinex multi-purpose two ram high capacity Baler to allow us to efficiently bale the metals and plastic prior to export from site.

Selecting our Supplier

When it came to selecting a supplier it was important to us that there was a clear understanding of our requirements: plant throughput & flexibility; recovered recyclate quality; process efficiency; operational reliability and availability; capital cost and the ability to deliver in a short time frame were all key aspects for us.

We engaged with a number of suppliers for technical proposals, whilst they were all of a high quality, we decided to select Machinex who we were already working with on our Materials Recycling and Fuel Preparation Plant. They had proved to us to be a company that were not scared to think outside the box so we had clear confidence in their ability to deliver a solution that would align perfectly with our requirements.

Future Proofing in an Ever Evolving Market.

Within the Plant design Machinex have included a number of future upgrades designed to further improve the quality of recovered materials and enhance their value. These include further glass clean up and separation of the plastics by polymer type. We intend to incorporate these upgrades once we have developed operational experience of the input mix and a clear understanding of off-taker requirements. We see the production of high quality recyclates and maximising value from these as key to the success of the facility in an ever-evolving market.

As Scotland moves towards having one consistent national system for household waste collection we fully expect to see further changes in how waste is separated at source, and therefore have focussed on delivering an efficient and flexible plant which can accommodate a range of material mixes whilst focussing on the quality of outputs.

To view the article on MRW please click here