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Maximizing Revenue at the City of Hamilton

Mass Balance Audit, Upgrades and New Machinex Optical sorter help improve PET capture rates and earning potential

Machinex' Mach Hyspec optical sorter at the City of Hamilton MRF.
Machinex' Mach Hyspec optical sorter at the City of Hamilton MRF.

After completing an efficiency and effectiveness (mass balance) audit on its container line in 2014, the City of Hamilton set to work on implementing a series of upgrades to improve its capture rates and revenue earning potential. The initial audit, commissioned by Ontario's Continuous Improvement Fund (CIF) and performed by a private consulting firm, estimated that the City of Hamilton could obtain approximately $700,000 in additional revenues annually if all of the material entering the container line were correctly sorted to appropriate grades. 

According to the CIF's Carrie Nash, "Although it's not realistic to expect a 100-percent capture for all materials, it was clear that revenue earned from the higher capture of just a few of the valuable commodities coming into the facility could allow for a payback on investment."

Nash explains that the mass balance audit involved using a sample of incoming materials, which are run through an empty line, including all bunkers and sort stations. "The goal was to find out to what extent the purity of processed materials matches the City of Hamilton's expectations. It also helps to determine how closely the performance of each piece of equipment matches its efficiency and effectiveness rating from the manufacturer."

Initial recommendations from the 2014 audit included upgrades to existing equipment and processes as well as the addition of a second optical sorter (in addition to a Titech PolySort 1400 DVB unit that has been in operation in Hamilton for many years).

One of the key upgrades included the reconfiguration of an existing film-grabber, used to remove film plastic at the front of the container line. 

"Film plastic often wraps around other materials and equipment, and the high volumes of it in the sorting system reduced the effectiveness of manual and mechanical sort stations," says Nash. "Fixing the film-grabber improved capture of higher value materials such as HDPE."

Jen Addison, the City of Hamilton's MRF project manager, explains that the film grabber acts as a vacuum hood, removing film plastic from the recycling process by air suction. "Managing film more effectively at the front of the line helps to unburden sort stations and the equipment that follow it," says Addison. 

To provide further efficiencies in separating film plastic from their line, the City of Hamilton also reprogrammed their Titech PolySort 1400 DVB optical sorter for the task and installed a residue clean-up line to limit the loss of commodities at the earliest stage of recovery. The Titech optical sorter now pulls out film plastic before it hits the residue line and ensures that manual sorters are able to more clearly see and pull valuable items. Separating out film plastics in this way is a novel application for an optical sorter.

"The Titech optical sorter has been reprogrammed to eject plastic film," explains Addison. "The benefits of this are realized in the residue recovery line that follows it. Prior to reprogramming the Titech, film plastic would have visually covered high value commodities on the residue quality control line, making them difficult to capture. By removing plastic film at this stage, high value commodities become visible, enabling recovery, which translates into potential revenue and decreased residue to landfill." 

Positively sorting PET with the new MACH Hyspec
Based on a key recommendation of the initial audit, the City of Hamilton added a second optical sorter designed to increase the capture of PET, which was being improperly sorted or lost to residue. The audit indicated that as much as 21 percent of PET (bottles, jugs and jars) entering the facility was being missed. Based on commodity values at the time, this represented a projected lost revenue earning opportunity of $302,500.

The new optical sorter, a MACH Hyspec using a Hyperspectral SWIR (short wave infra-red) detection system, from Machinex Industries Inc., was installed in November, 2016. 

"The new Machinex optical sorter is currently programmed to positively sort PET material," explains Addison. "We're monitoring its post installation performance closely, and while early, all signs indicate that PET capture rates have risen significantly." 

Addison says another study will be undertaken to quantify the extent to which the new optical sorter has increased the capture of PET and reduced the material burden on downstream equipment, thus improving the capture of other high value materials that had previously been lost as residue.

Audit value
Prior to the reconfiguration of their film-grabber and Titech PolySort unit, and addition of the Machinex optical sorter, the City of Hamilton estimates that as much as 13 percent of aluminum food and beverage cans, at an estimated value of $172,300, were being lost. This was in addition to 20 percent of HDPE, at an estimated value of $113,800.

"Staff has been busy implementing measuring and monitoring controls to determine the extent to which they are continuing to improve over the baseline metrics detailed in the audit report," said Addison. "We're keeping in close contact with CIF and look forward to sharing further updates as they become ready." 

She adds that after their experience over the last several years, the City of Hamilton is convinced that auditing identifies meaningful opportunities for improvements, and that by pursuing those opportunities, it pays off. 

"Completing a processing audit on the container line identified opportunities for improvements that would lead to increased material capture and revenue earning potential," says Addison. "It helped rank the upgrade opportunities on the basis of those which provide the greatest return on investment, in addition to laying the ground work for longer term capital planning strategies." 

This article was originally published in Recycling Product News, April 2017, Volume 25, Number 3

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