Thesis Details

Thesis Title: An Evaluation of the Effect of Ultraviolet Light and Hydrogen Peroxide Photochemical Oxidation Technology on the Decomposition and Decolorization of Textile Dyestuffs
Thesis Author: David Wyatt II
Abstract: The number of environmental regulations has increased over the past twenty years. The trend indicates that the government will continue passing legislation that impacts the textile industry. One specific area of expected change regards the presence of color in released effluent. Some states currently enforce state laws regulating color release; however, a federally mandated color release limit does not currently exist--but one is anticipated in the near future. Numerous waste treatment technologies exist that reduce color in effluent and improve overall water quality. One technology, chemical oxidation, appears to hold the greatest potential for future use in the textile industry--especially for color removal. The primary objective of this thesis was to determine the potential of ultraviolet light/hydrogen peroxide (UV IH20J photochemical oxidation technology in treating textile dyes. Additional objectives included determining the effects of dyebath concentration, radiation intensity, and hydrogen peroxide level on a UV IH20 2 system's ability to decompose and decolorize organic material. To anticipate the economical viability of the UV IH20 2 technology, calculations projecting the scaled-up operating costs were also completed. Results indicate that acid, direct, basic, and reactive dye classes appear to be viable candidates for further in-plant treatment trials using photochemical oxidation treatment technology. Dye structures specifically involved in this research included: disazo, azo, stilbene, polyazo, oxazine, triarylmethane, disazovinyl sulphone, and triazinyl. The disperse and vat dye classes do not appear to be viable for future inplant trials. Limited dye solubility seems to have hindered the hydroxyl oxidation of these dye classes. Only anthraquinone and indigoid dye structures were involved in the evaluation of these classes. It was also found that as dye concentration increases, the treatment time required to reach the same percent color reduction also increases. In addition, as radiation intensity increases, the treatment time required to reach certain levels of color, COD, and TOe reduction decreases. Furthermore, as peroxide concentration increases, the treatment time required to reach certain levels of color, COD, and TOe reduction decreases. For some dyes, it was found that the rate of COD reduction was slower than the color reduction rate. After evaluating respective trials, the projected ope~ting costs of a full-scale UV IH20 2 treatment system treating different dye class feed concentrations (20 to 2520 ppm) ranges from $1.89 to $44.92 per 1000 gallons treated. At low feed concentrations, the cost is more comparable to an activated sludge system. IDtraviolet light/hydrogen peroxide photochemical oxidation treatment technology will not serve as a universal answer to waste treatment opportunities. However, in a qualified atmosphere and in conjunction with an overall well designed treatment facility, chemical oxidation can serve the textile industry well.