Responding to the need to clean up their fibre commodities to meet the increasingly higher demands of the end markets, EWSWA decided to upgrade their fibre line by installing an optical sorter to remove “browns” (cardboard and boxboard), containers and other contamination from its newsprint bales (Sorted Residential Paper #56 or SRP#56). What they learned along the way provides valuable guidance for all Blue Box program operations.
Improvements upstream ensure success of optical sorter
An optical sorter is designed to work under a specific set of parameters. Its performance is dependent on variables such as material mix and burden depth. While the optical sorter was the focus for EWSWA, smaller upgrades upstream were also needed to ensure the processing line would run optimally.
In 2019, EWSWA addressed just this to ensure the success of its optical sorter by refurbishing its Old Corrugated Cardboard (OCC) screen and installing a new fines screen upstream of their new optical system. To evaluate this investment, the EWSWA hired EcoCompass Inc. to conduct Material Recovery Facility (MRF) Mass Balance and Efficiency Audits before and after these system changes to quantify the improvements in quality and capture rates as a result of the new equipment.
Refurbished screen improves OCC, Hardpack and SRP#56 streams
In 2016, EWSWA conducted a Mass Balance Audit and identified the existing OCC screen was only capturing 50% of the cardboard moving through the fibre line. Missed OCC was increasing the workload for sorters downstream who were only able to gather an additional 21% bringing the total OCC capture to 71%. This missed OCC ended up in either a lower value grade (Hardpack), or in the newsprint bale as contamination. With tightening end markets, this increased the risk of SRP#56 being rejected or downgraded.
After EWSWA refurbished their OCC screen, the capture rate of OCC increased to 85%, a 35% higher capture rate than the previous OCC screen. It resulted in less burden on all downstream sorting activities and contributed to the improved capture of Boxboard into Hardpack from 28% to 67%. The higher capture of OCC and Hardpack also resulted in a significantly improved quality of SRP#56.
2016 & 2019 Material Capture Rates for the Fibre MRFNote, this table reflects combined capture rates achieved by the various pieces of equipment and the manual sorters.
|Material||Year of Study||Targeted Commodity: OCC||Other Commodities & Residue|
|Material||Year of Study||Targeted Commodity: Hardpack||Other Commodities & Residue|
Better sorting improves potential to earn higher revenues
Previously, OCC missed by the old screen was recovered with Boxboard and sold as Hardpack. This resulted in a missed opportunity to earn a higher revenue. The mass balance study in 2019, after the upgrades, indicates that EWSWA separates out approximately 13% more OCC annually from other lower revenue or residue streams. The higher revenue earned from capturing more OCC will contribute to a quicker payback on their OCC screen investment (i.e. two years or less depending on market conditions).
What is equally important is that sorting OCC into the appropriate grade reduces the burden downstream, which in EWSWA’s case also resulted in improved newsprint (SRP#56) bale quality. This helped maintain their end market for the SRP#56 by ensuring sustainability of meeting the material specifications.
A new, or refurbished OCC screen is a lower cost investment, in terms of MRF operations, but its impact is significant, especially with the rise of e-commerce, which is increasing the volume of OCC, as well as introducing new sizes of OCC to be managed.
To find your opportunities for small wins, prioritize data collection. A mass balance study is one method. It examines the flow of materials through your facility and determines where commodities are missed and/or incorrectly sorted, and it can be carried out for between $30,000 to $50,000 per study. It’s another example of a low-cost investment that carries a high value. This along with other data tracking efforts like it, help identify opportunities for strategic spending, which will be critical to maintaining efficiency and effectiveness and to supporting new, higher end market demands while we await transition.
For more information about this initiative, please contact Carrie Nash.