Online monitoring and control of colour removal process in textile waste water

Abstract

Removal of color from the dye wastewater prior to discharge to local sewage treatment facilities or adjoining water courses is one of the environmental problems being faced by textile industry. Color removal is a highly non-linear process, which makes controlling the process in continuous mode more complex. For safety conditions most industries run plants in batch process, but the process has to be run in continuous mode in order to maximize productivity. For the past two decades, several physico-chemical methods like adsorption, chemical treatment and ion pair extractions were adopted and were proven to be costly and less effective. Biological treatment methods are comparatively cheaper and are considered to be the best alternative, having proper analysis and environmental control. With this in mind, an attempt was made to evaluate the efficiency of this new innovation in color removal technology. Aneurinibacillus aneurinilyticus microbes are used to decolorize dye solution with mixed microbiological cultures in continuous mode operation. Maximum efficiency can be attained through the continuous mode, but the problem lies in closed loop and in continuous process. In order to overcome this problem a perfect controller with suitable control modes have to be designed. OD (Optical density) of the sample dye and the treated wastewater can be measured by TMS3200. Standardization of sensor can also be done by spectrophotometer readings, the percentage of degradation of color can be obtained by comparing the OD of the sample dye to that of the treated water. The sample dye taken for the study was collected from the equalization tank in Common Effluent Treatment Plant (CETP), Tirupur. The main objective of the project is to obtain above 90% decolorized treated water by implementing suitable control algorithm. Implementation of Feedback and feed forward control scheme with digital control algorithm will increase the competence of the decolorizing process as compared to batch process.