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Abstract:
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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.
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