ONLINE MONITORING AND CONTROL OF THE TEXTILE WASTE-WATER COLOR REMOVAL PROCESS

On-line monitoring of the wastewater color and ORP values is used to carry out laboratory studies for collecting data to assist in formulating model equations that can be used to achieve better control and automation of the oxidation process for color removal from textile finish wastewaters. Laboratory studies show that the ORP value, the solution pH, the chemical dosage applied and the resulting color of the treated samples are well correlated by linear relationships. Additionally, the ORP value of the solution that is highly related to the color or the ADMI value of the sample being oxidized can be used as a control parameter of the oxidation process. Nernst equation is modified to generalize the findings and the reaction kinetics can be delineated by C-1 = 1n (ADMI(0)/ADMI(1)). The term C-t is a function of ORP, pH and reaction time while ADMI and ADMI(t) are the color of the raw wastewater and the treated effluent, respectively. Using the model, the dosage requirement, the color removal efficiency, and the time required to complete the oxidation reaction can be calculated. On-line monitoring and automatic control of the de-coloring process to achieve a more efficient and better cost-effective color removal can be made practical.