Sludge-based – or “reclaimed pulp” - beddings are made with fibers that are collected from pulp mill sewage systems

Sludge is defined as a muddy or slushy mass, deposit, or sediment. In the case of pet bedding, it is the solid matter produced by water and sewage treatment processes.

These types of pet beddings are made of “solids” discharged from pulp mill sewage systems. Most pulp mills have an acid sewer and a basic sewer that blend together and dump into a large settling pond called a “clarifier.” The solids that are too small to make paper, combined with the “wash up water”, drain into the clarifier where the heavy particles settle to the bottom. These particles are then collected, screened to take out big chunks, “dewatered” through the use of a chemical flocculent, and then dried to create the bedding.

The color of the waste product varies with the different solids that make it into the sewer on a particular day, or because the sludge is collected from different paper or pulp mill products. The darker grey sludge is usually from the fly ash removed with the other exhaust pollution by scrubbers on the exhaust stacks. Some pulp mills have different sewers for bathroom waste but some older mills do not.

Some pulp mills use chlorine bleach on the paper fiber, which can create Dioxin.

Though the paper industry has made efforts to rid their waste streams of the most troubling compounds, tests conducted by independent laboratories (initiated by AWF) showed that detectable amounts of Dioxin remain in all samples of the reclaimed pulp paper beddings tested.

These tests showed that traces of Dioxin were present in gray and brown paper bedding products to a Toxic Equivalency Quotient (TEQ) of between 0.1 ng/kg (nanograms per kilogram) and 0.75 ng/kg. (A product with a TEQ of more than 0.75 ng/kg is considered unacceptable for human consumption.)