ANALYSIS OF COD VARIATION IN WASTE WATER FROM A CONTINUOUS DEXIZING PROCESS

抄録

In order to predict the variation of COD in waste water from a continuous desizing process in real dyeing industries, a simulation model is proposed. It is based on a principle of mass transfer through a very thin stagnant film. An experiment was conducted by using a small tank and mass transfer coefficients included in basic expressions were determined. The calculated values by using the simulation model agree closely with the observed values in a real process. Moreover, in this simulation model removal rate and COD in 1st and 2nd units are especially high, which is in agreement with the fact that attempts to recover PVA sizing agent from wash water in 1st and 2nd units are actualiy being made. These results suggest the validity of this simulation model. The simulation indicates that the temperature of wash water and the velocity of fabric have a great influence on desizing but an influence of the quantity of wash water on it is not so great. It is found that an adoption of counterflow method can save considerable amount of wash water.