The basic recipe for paper is wood, water, and energy. First, trees are harvested and transported to the paper mill. Logs are cleaned and the wood is turned into small chips. Water is added to the chips and, using chemical or mechanical processes, turned into watery pulp. This solution is sprayed onto a long, wide screen called a wire. Water drains out and is recycled over and over again (the original use for grey water). The fiber mat that remains on the wire is squeezed by felt rollers until the pulpy stuff is about 60% water. The wet pulp passes through heated, steam-filled metal cylinders (like wringers on vintage washing machines) many times, gradually turning into paper. The paper gets a uniform thickness by passing through big, heavy cast iron rollers called a calendar. At the end of the line is a roll of paper as wide as 30 feet.

Recycling adds fibers from previously made paper to the pulp mix. This isn’t as easy as it may sound. As much as 20% of what goes into a recycle bin can’t be used. Trash, such as staples, paper clips, wire and plastic must be screened out and sent to a landfill. Inks, coating and adhesives must be removed. Some fibers may have been recycled many times before and are now too short to produce paper. These will simply stay in the wastewater. Fibers get shorter and shorter with each recycle and can only be used five to seven times. Producing pulp from wastepaper requires more energy than creating pulp from virgin wood because the fibers must be broken down mechanically.

Collecting recyclable paper is still one of the most expensive aspects of paper recycling. The process involves sorting the paper into categories, baling it, and transporting it where it will be re-pulped. The paper is put into large vats where it is soaked, reducing it into fibers. When ink starts to separate from the fibers, chemicals are added to prevent the ink from reattaching to the paper fibers. The pulp goes through a series of screens to remove ink and additives and is cleaned several times with heat and chemicals to remove additional ink. The pulp then enters a floatation device, where a chemical mixture containing calcium soap is introduced. Air bubbles form causing any remaining ink to float to the surface where it can be skimmed away. After the de-inking process, the pulp is ready to be made into paper and related products, just as if it were pulp that had been made from wood chips.

Even with all this extra work, using recycled paper is more energy-efficient and environmentally friendly than cutting down trees and transporting them to a paper mill. And it keeps – literally – tons of paper from going to landfills.