NUR and our relationship in BNR processes with sewage at different temperatures and its design application

Denitrification is known as an essential part of a biological nutrient remo val (BNR) process to remove nitrogen and it also affects phosphorus removal . However, an accurate prediction of nitrogen removal is extremely difficul t because there are too marry factors involved. This study was conducted to find a relationship between nitrate uptake rate (NUR) and carbonaceous oxy gen uptake rate (OUR) and develop a simple method to predict applicable NUR for the design of various BNR processes. Sewage was subdivided into solubl e and particulate organic fractions. NUR/OUR ratios were measured by respir ometer with these organic fractions and the rest sludges grown at various B NR processes and temperatures. NUR/OUR ratios were varied with the types of organic fractions of sewage and temperature. The NURs predicted from the N UR/OUR ratios and computed OUR based on the total tank volume of anoxic and oxic stages with the influent sewage characteristics were very much compar able with the observed NURs from various BNR processes. (C) 2001 Elsevier S cience Ltd. Ali rights reserved.