ABSTRACT Because nitrogen compounds such as ammonium, nitrite, and nitrate are toxic to aquatic species and cause eutrophication in natural water environments, the removal of total nitrogen from wastewater has become a worldwide emerging concern. Although activated sludge technology is old, it has proven to be effective in the removal of nitrogen compounds until now. The objective of the studies of the pilot plant is used an internal mixed liquor recycling pump (IMLRP) with varied rates ranging from one to fifth of influent flow to optimize nitrogen component removal, similar to the recycle activated sludge (RAS) approach. There was also no clear value for the amount of recycled activated sludge (RAS) flow between, but it was an optional value ranging from 1 to 3. So these studies evaluated the economic rate of the internal mixed liquor pump. The pilot plant consists of three tanks, the first and second tanks in a pilot plant are rectangular, while the third, which serves as the final sedimentation tank, is spherical with a conical bottom. The arrangement of the pilot plant was as follows: the first tank was an anoxic tank, followed by an aeration tank (A.T), and a final sedimentation tank, using (IMLRP) rates ranging from (1–5) influent flow, an average dissolved oxygen (DO) of 2.5mg/l in the anoxic tank, temperature ranging from (18–21), and pH ranging from (6.5–8), the total nitrogen removal in this process with rate of (IMLRP) equal twice of influent flow and achieves 64.5% of total nitrogen removal.