Stabilized material from the anaerobic digestion process, now referred to as biosolids - in recognition of its potential to be "beneficially recycled," are run through a device known as a belt press. Aided by a chemical product called a polymer, large amounts of water are removed, and the material is consolidated to a thicker and dryer form. The dewatered biosolids can now be readily hauled by truck to agricultural fields where nutrients (nitrogen, phosphorous, potassium, etc.) contained in the biosolids can be recycled back into the soil. Before land application is permitted, biosolids must meet a number of quality requirements established by the U.S. Environmental Protection Agency and the Washington State Department of Ecology.