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Abstract:
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Chemical usage has increased dramatically in the past
several decades. Conventional wastewater treatment methods
are capable of treating residuals, to a certain degree.
The untreated residuals that are discharged from treatment
facilities are undesirable and may be potentially
hazardous. Textile chemicals of concern may range from
salts to dyes to heavy metals. A great deal needs to be
learned about their performance in wastewater treatment and
in the environment. This thesis establishes the inhibition
effects that selected textile salts and surfactants have on
biological treatment systems.
The thesis evaluated the response of treatment bacteria
to increasing levels of sodium chloride, sodium sulfate,
and two nonionic surfactants (an alcohol ethoxylate, AE,
and an alkylphenol ethoxylate, APE). The treatment
bacteria were adjusted in the laboratory to low, average,
and high concentrations that are typically found in textile
and municipal treatment facilities. The target
concentrations were 1000 mg/l, 3000 mg/l, and 5000 mg/l.
EC50 (the concentration of chemical that resulted in a
50 percent reduction in bacteria respiration) and the Inhibition Threshold, IT (the concentration of chemical
that had no effect on bacteria respiration), were obtained
for all of the chemicals at all concentrations of bacteria.
The concentration of bacteria had no effect on bacteria
respiration when additions of sodium chloride were made.
However, when sodium sulfate, alcohol ethoxylate
surfactant, and alkylphenol ethoxylate surfactant were
added, significant differences in respiration occurred
between the different concentrations of bacteria.
Data from this research is classified as "preliminary
work" and is not intended for regulatory use.
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