A hydraulic debarker is a machine removing bark from wooden logs by the use of water under a pressure of 700 kilopascals (100 pounds per square inch) or greater.
Debarking water may be recycled after effective settling, but suspended solids may increase wear on high-pressure pumps.
Men called peelers removed bark from fallen trees in the woods through the early 20th century, but the process was dangerous and labor intensive.
The United States Environmental Protection Agency published hydraulic barking category effluent limitations in the 1970s.
Wastewater discharged from debarking could average no more than 2.5 pounds of biochemical oxygen demand (BOD) and 12 pounds of total suspended solids (TSS) per thousand board feet of lumber produced (0.5 kg BOD and 2.3 kg TSS per cubic meter of lumber).