How Single Stream Recycling Works at LHSC

Illustration showing a front end loader dumping recycling items onto a conveyor belt and being sorted by people. The sorted items then go through a mechanical sorting process for separating cardboard from the rest of the items.
This illustrates the initial sorting process at a Material Recovery Facility.

Published: 2024-03-19    Author: Ken Edwards

Single stream blue box recycling plays a critical part in reducing London Health Sciences Centre’s (LHSC) environmental footprint. But have you ever wondered what happens to your recyclables after they are collected? One essential part of the recycling process occurs at Material Recovery Facilities (MRFs), where these materials are sorted, processed, and prepared for reintegration into the production cycle.

The Role of Material Recovery Facilities

Material Recovery Facilities are large-scale recycling centres where mixed recyclables are separated, cleaned, and processed for further use. MRFs are the bridge between curbside collection and the industries that will convert these materials into new products.

Although arrangements vary across the country, in London, the city owns a facility that is operated by Miller Waste. Regulatory compliance of these facilities is overseen by the Resource Productivity and Regulatory Authority (RPRA) under the Ministry of Environment, Conservation and Parks.

Collection and Delivery

Recyclables collected from homes and businesses are transported to MRFs directly or through an intermediate transfer station. At this stage, materials can sometimes be lightly contaminated due to mistakes in mixing non-recyclables with recyclables by the initial people recycling or even at the transfer station.

Recycling collection trucks dumping their collected material directly on a tip floor at the MRF
Material is transported to a transfer station and/or directly to an MRF and dumped on a tip floor.

Initial Sorting

Once the materials arrive at the MRF, the first step is to separate them into broad categories. Conveyor belts, rollers, and other equipment are used to move the recyclables along, while manual labour is also involved. Common categories include paper, cardboard, plastic, glass, and metal.

Photograph of manual sorting stations for incoming recyclable material with large bunkers underneath that collect the sorted materials together.
Bunkers are located beneath the sorting line to easily sort by material type.

Automated Sorting

MRFs utilize various technologies, such as optical sorters, magnets, eddy current separators, and air classifiers, for the efficient sorting of materials. Optical sorters, for instance, can identify and separate different types of plastics based on their polymer composition. Magnets are effective for removing ferrous metals like steel cans, while eddy current separators can separate non-ferrous metals like aluminum.

Photograph of empty plastic bottles coming off a conveyor belt
Conveyors take various materials to be sorted along the line.

Baling and Shipping

Once the materials have been sorted and contaminants removed, they are compacted into bales or bundles for transportation to manufacturing facilities. Bales make the shipping process more efficient and cost-effective. For instance, cardboard and paper are commonly baled together, while plastics, metals, and glass are processed separately.

Photograph of baled materials which are large compressed cubes of similar recycled products such as plastic bottles.
Bales of #PET Plastics are baled and ready for shipment

Quality Control and Contamination Management

The goal at MRFs is to recover as much recyclable material as possible. However, some contamination is inevitable when items are placed in the wrong bin or the wrong compactor. Contaminants like food waste, non-recyclable plastics, and other non-recyclables (e.g. masks, gloves, disposable gowns) must be removed. 

While MRFs have quality control processes in place, including manual inspection, air blowers, and screening technologies to minimize contamination levels, these facilities are simply not equipped to handle high volumes of these waste materials. As shown in the pictures below, non-recyclables in the recycling stream can pose a safety hazard to MRF line workers and can cause damage to sorting equipment.   

Photograph of line workers sorting through the incoming recyclable materials and pulling specific items, like plastic bags, into their own bin.
MRF line workers sort through several tons of material per day.
Photograph of a mechanical material screen jammed with items that should not have entered it.
Non-recyclable material jammed in a screen at a MRF.


Material Recovery Facilities and their workers are critical to recycling. They play a vital role in transforming our recyclables into valuable resources for new products. Even when recycling is lightly contaminated, MRFs have the technology and expertise to ensure that these materials  can still be recycled effectively. Along with ever improving technology, evolving methods, and new initiatives to improve efficiencies in the recycling industry, it is essential for all of us to do our part by understanding what can and can’t be recycled and by recycling responsibly to support ongoing recycling efforts. By working together, we can continue to reduce waste, conserve resources, and protect our environment for future generations. 

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