PURE OXYGEN DESORPTION METHOD - A NEW AND COST-EFFECTIVE METHOD FOR THE DETERMINATION OF OXYGEN TRANSFER RATES IN CLEAN WATER

摘要

Many clean water tests with the well known absorption method using sodium sulphite for deoxynation have shown that there are problems connected with solving these chemicals. Because of this, a new test method was developed at the Darmstadt University of Technology to determine oxygen transfer rates fine bubble aeration systems without sodium sulphite and a cobalt catalyst. The new method is called "Pure oxygen desorption method". Contrary to the absorption method, the oxygen concentration in the test tank is increased well above the normal oxygen saturation concentration. This high excess concentration is obtained by feeding pure oxygen into the main pipe of the fine bubble aeration system. After starting normal aeration, the oxygen concentration in the clean water decreases towards the oxygen saturation concentration by stripping of the excess oxygen. The desorption curve is used to calculate the parameter aeration coefficient k_La and oxygen saturation concentration under process conditions c_∞~*. In comparison to the absorption method with sodium sulphite, the pure oxygen desorption method is a simple and cost-effective method for determining oxygen transfer rates.