4.1.3 Contaminated Water


 Contaminated water was prepared by dissolving chemical

compounds into distilled deionized water. This approach was

chosen because it is easier to control concentrations and

would tend to have a consistent characteristic throughout

the course of the study.


4.1.4 Microorganisms


 The microorganism seeds were taken from the return

sludge in the aeration tank of the University of Florida's

wastewater treatment plant. Unless otherwise specified, the

sludge was used without further treatment. The supernantant

of sludge, if used, was siphoned out after the sludge was

blended by a blender and settled.


 4.2 Analytical Methods


4.2.1 Chemical Concentration Determinations


 Organics analyses. Phenol, 2,4-dichlorophenol and

pentachlorophenol concentrations were analyzed by a high-

performance liquid chromatography (HPLC), Perkin-Elmer Model

LC-100, with a ZORBAX C-8 column (4.6 mm I.D. x 15 cm), a

LC-75 Spectrophotometric Detector and a Fisher Series 5000

Recorder. For phenol and 2,4-dichlorophenol determination,

a 58/42 (v/v) mixture of methanol/water mobile phase was

used and the wavelength of the UV detector was set at 197

nm. A 72/28 (v/v) mixture of methanol/water mobile phase