As an expert in the field of recycling, I am often asked about the process of sorting recyclable materials. Many people are curious about how their plastic bottles, paper, and glass end up getting recycled. The truth is, recycling is a complex process that involves a combination of machines, technology, and equipment, all working together to sort different types of materials from the recycling stream. This process takes place in a material recovery facility (MRF), where our recyclable materials are sent. Once the materials arrive at the MRF, they are unloaded onto a conveyor belt where employees carefully remove any non-recyclable items.
This step is crucial because any contamination in the recycling stream can render an entire batch of materials unusable. The next step in the sorting process involves using gravity to separate the materials. Paper, which is lighter, moves upward on the conveyor belt while the rest of the material moves downward. Magnets are then used to separate most metals from the rest of the materials. Plastics are either sorted by employees or, increasingly, by optical technology. A drum feeder is used to evenly distribute the recyclable materials onto a conveyor belt.
From there, a separate conveyor system moves the materials to a different area on site where they are ground into coarse-grained sand and then shipped off to glass recyclers. One of the most important machines in the sorting process is the magnetic metal classifier. This powerful magnet passes over the conveyor belt and attracts anything magnetic, which usually only accounts for about 4% of the total recyclable material. The initial sorters play a crucial role in removing any plastic bags, hangers, or other items that could jam up the sorting machines. They also remove any materials that cannot be processed through the machines. With the rise of single-stream recycling, the process has become more streamlined. In this system, all recyclable materials are placed in one container and then delivered to a MRF, such as Willimantic Waste Paper in Willimantic, Connecticut.
While this system is not perfect and can result in some broken glass contamination, its simplicity has led to an increase in recycling rates. One of the biggest challenges with recycling is getting people to properly separate their materials before placing them in the recycling bin. However, with single-stream recycling, this step is eliminated, making it easier for people to recycle. Glass is one of the heavier materials in the recycling stream and is separated using a glass classifier. This machine uses star-shaped screens to separate glass from plastic and aluminum. The glass then falls into containers below and is sent off to be recycled. At the MRF, a highly automated system of conveyor belts, screens, magnets, and lasers is used to sort the materials into different categories.
These materials are then sold to metal-plastic recyclers and paper mills. While single-stream recycling has made the process more efficient, it has also led to confusion among consumers about what can and cannot be recycled. To combat this issue, new MRFs are using advanced optical technology, cups, magnets, and other mechanical solutions to better sort recyclable materials. Despite all of this advanced technology, there is still a need for employees to manually sort through the materials that the machines may have missed. This is especially true when it comes to removing non-recyclable items, such as plastic bags, from clogged machines. As we become more aware of the impact of our actions on the environment, it is important to understand the intricate process of recycling. By properly sorting our materials and supporting advancements in recycling technology, we can all play a role in creating a more sustainable future.