Composting is the natural process of recycling organic matter into a rich soil amendment called humus. Paper towels, derived from wood pulp, are generally biodegradable and contribute beneficial carbon to a compost pile. However, their suitability depends entirely on the manufacturing process and what substances they have absorbed during use. To ensure a healthy compost environment, one must carefully consider the material’s original properties and avoid introducing harmful contaminants.
Criteria for Compostable Paper Towels
The paper towel must meet certain criteria before it is deemed safe to compost. Although the material is primarily cellulose fiber, processing often introduces substances problematic for microbial life. Unbleached paper towels are preferable because they avoid chlorine-based bleaching agents. These chemicals can introduce dioxins and other pollutants into the final compost.
Choosing towels made from virgin wood pulp or recycled paper requires scrutiny. If recycled, the paper must have been processed without harsh de-inking chemicals. Towels with bright colors or printed patterns should be excluded, as the dyes and inks might contain heavy metals or toxins that harm beneficial microorganisms. The safest choice is a plain, unbleached, and undyed paper towel, ideally certified as Process Chlorine Free (PCF) or Totally Chlorine-Free (TCF).
Contaminants That Ruin Composting
Once used, the substances soaked up by the paper towel become the primary factor determining its compostability. Many common household contaminants will either kill decomposition microbes or attract unwanted pests. Paper towels used with chemical cleaning products, such as bleach, ammonia, or strong disinfectants, must be discarded in the trash. The active ingredients in these cleaners are designed to kill bacteria, which means they will eliminate the healthy populations of microorganisms necessary for the composting process.
Towels saturated with grease, cooking oils, butter, or large amounts of dairy residue should also be kept out of the compost. These fatty substances coat the organic material, preventing air and water from reaching the microbes. This creates anaerobic conditions that slow decomposition and lead to foul odors. Furthermore, meat, dairy, and heavy oil residues are known to attract rodents and other nuisance pests to the compost area.
Paper towels used to clean up human or animal waste pose a serious risk due to potential pathogens. While the high temperatures of a properly managed hot compost pile can kill many of these disease-causing agents, home composting systems often do not reach or sustain the necessary heat levels. Therefore, to prevent the spread of bacteria or viruses, any paper towel contaminated with bodily fluids should be disposed of outside the compost system.
Integrating Paper Towels into the Compost Pile
Paper towels are classified as “brown” material because they are dry, fibrous, and rich in carbon. Brown materials must be balanced with “green” materials, which are rich in nitrogen, such as fresh food scraps or grass clippings. A general guideline suggests maintaining a carbon-to-nitrogen ratio of approximately 25 to 30 parts brown to 1 part green by weight. This ratio ensures optimal microbial activity.
To ensure the paper breaks down efficiently, tear or shred the towels into smaller pieces before adding them to the pile. Reducing the material size significantly increases its surface area, making it easier for microbes and fungi to consume the cellulose fibers. Adding towels in large, wadded clumps leads to slow decomposition and dry pockets within the pile.
The brown material should be layered throughout the compost pile, alternating with green materials to maintain aeration and moisture balance. Paper towels are highly absorbent, so wetting them slightly before introduction helps kickstart decomposition and prevents them from absorbing too much moisture from other components. The overall compost must remain damp, like a wrung-out sponge, to support the microbial community.