Recycling is commonplace today in eastern Massachusetts, with curbside pickup of household recyclables in most communities and drop-offs for items such as electronics—significant progress since the days when Boston Building Resources served as a recycling drop-off site for city residents. So, once it’s been collected, where does it all go? Here’s a quick overview, courtesy of Earthworm Recycling.
Paper is essentially matted plant fiber from trees. Recycling extends the lifespan of this plant fiber, saving energy and reducing the need for logging. When newspaper, office paper, and cardboard are collected, the material is brought to a recycling center and prepared for shipment to paper mills. Mills need the recycled materials to be uniform and free of contaminants (such as metals or plastic) so they can produce consistent consumer products (such as bathroom tissue). This is one reason why recycling centers have rules and why they inspect and sort incoming recyclables. For instance, pizza boxes can be recycled as long as any oily parts are removed.
Paper collected in the Boston area is usually brought to sorting and baling facilities (including one in Charlestown), which have contracts with particular paper mills. The paper is weighed and dumped onto an indoor tipping floor, then pushed by a front-end loader onto a six-foot-wide conveyor belt that takes it past a line of employees who pick out contaminants. Next, it is chopped, compacted, and bound into hay-bale-like cubes for shipping to mills throughout North America and sometimes overseas.
At the mill, the paper is unbaled and put into a hydro-pulper—something like a giant blender—where water is added to create a slurry with an oatmeal-like consistency. After de-inking agents are added, the slurry is pressed into large sheets, dried, and rolled. These enormous rolls of paper (imagine a roll of bathroom tissue the size of a car) are sent to be trimmed and cut into commercially marketed products.
Each time paper is recycled, the plant fibers become shorter, which lowers the quality of the paper that can be made from it. For this reason, paper is often recycled into disposable products. Cellulose insulation is made from recycled newspaper treated with a fire retardant.
Recycling one ton of paper saves enough energy to power the average American home for six months, conserves 7,000 gallons of water, saves 3.3 cubic yards of landfill space, and spares 17 trees. Nationwide, nearly 45 million tons of paper and paperboard were recycled in 2010.
The Environmental Protection Agency estimates that plastic accounts for about one-fifth of all waste. Thankfully, recycling of plastics has increased substantially over the past 20 years. A numerical coding system (the number on the bottom of your yogurt cup or drink bottle) helps recyclers identify and sort different types of plastic.
The recycling process begins with mechanically sorting containers according to their numerical codes. Individual plastic types such as polyethylene terephthalate (PET, #1, soda and water bottles) or high-density polyethylene (HDPE, #2, milk and detergent bottles) are compacted into bale-like cubes for shipment. Sometimes, plastic is shredded and shipped to reuse mills as flakes.
Recycled PET is widely used, especially for textiles (including polar fleece). Carpet companies can often use 100% recycled resin to manufacture polyester carpets. PET can be spun like cotton candy to make fiber filling for pillows, quilts, and jackets. A substantial quantity goes back into the bottle market. HDPE is ground into small flakes, which are washed and floated in water to separate them from contaminants. The cleaned flakes are then dried in a stream of hot air. Sometimes the plastic is pelletized, creating little beads that can be used in injection molding presses to create new products, such as plastic lumber, pipes, and trash cans. Ivy rain barrels available at Boston Building Resources are made from 50% recycled HDPE.
The most commonly recovered metals from nonindustrial waste are steel and aluminum, used to make food and beverage cans. Steel food cans contain at least 25% recycled metal. About two-thirds of aluminum cans in the U.S. are recycled. Recycling metal has far-reaching benefits; of all toxins released by industry, about 40% comes from hard-rock mining operations.
After being collected, steel and aluminum cans are separated mechanically, crushed, baled, and shipped to remanufacturing mills, where the material is used to make new cans. It is estimated that scrap aluminum can be back on the grocery shelf as a new container in as little as 60 days.
Glass is made mostly from sand (silica), much of which is mined in coastal states such as New Jersey. Other mined minerals, including soda ash and limestone, are also part of the centuries-old recipe for making glass. When separated by color, glass can easily be recycled into new glass containers an unlimited number of times.
Single-stream recycling, where all materials are mixed together for collection, creates a challenge for glass recyclers. A significant amount of glass is broken or pulverized, and the colors become mixed together, making the glass less marketable or even unusable. While single-stream recycling is convenient for homeowners, the only certain way to keep the glass recycling loop going is to take it to a redemption center. A directory of redemption centers is available from Earth911.com; call first to see what they accept.
Recovered glass goes to a processing plant where contaminants such as paper, plastic, and metal are removed. Then it goes to one of seven mills nationwide that turn the cleaned, crushed glass into new glass packaging. Today, a typical glass container is made up of as much as 70% recycled glass. Glass can go from the recycling bin to the store shelf in as little as 30 days.
Want to learn more?
Here are some sources for further information.
- Earthworm Recycling—a nonprofit recycler in Somerville, which handles the business recycling needs of Boston Building Resources. Click the “Explore” tab at earthwormrecycling.org for more extensive information on “where it all goes.”
- MassRecycle—a statewide coalition that promotes recycling and the use of recycled products, online at massrecycle.org.
- City of Boston Recycling—details about which items can and cannot be recycled through Boston’s curbside pick-up program. Search for “recycling directory” at cityofboston.gov. Residents of other municipalities should contact the recycling coordinator at the city or town hall.
This article originally appeared in the Summer 2012 issue of BBR's HandsOn newsletter.