The capacity of particulate organic matter to act as a carbon source for denitrification is a significant concern in wastewater treatment facilities. The biodegradability of particulate matter is essential to its applicability. This research aims to ascertain the role of particulate organic matter in denitrification by classifying COD, conducting pre and post denitrification tests, and analyzing the oxygen utilization rate (OUR) profile of respiration. A pilot plant was established and operated utilizing an Oxic-Anoxic-Oxic (OAO) system throughout four different loading stages, with unsettled raw wastewater as the influent. Following prolonged operation, the best removal efficiencies of OAO process for TCOD, BOD, TN, and NH