Pipeline integrity testing is carried out by filling the line with water and pressuring it to specified levels for a period of time. One by-product of this type of test is a huge volume of water, which is usually contaminated with organic materials. Another common form of pipeline integrity testing is known as intelligent pigging. A pig is a tool which is pumped through the pipeline for several purposes including to insure it is unobstructed & open, to perform maintenance tasks on the interior of the line or to conduct sophisticated monitoring procedures that identify to the client if an abnormality exists anywhere along the line's length.