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desorbed PCP due to biodegradation, therefore these two sets

of results define an upper limit and a lower limit for the

degradation rate constants and half-lives for each sample.


5.4.1 Nutrient Requirement.


 The purpose of this test was to determine how much, if

any, nutrient is needed for the biodegradation of phenolic

compounds in this particular type of soil. Background

analyses indicated that there was enough soluble phosphorus

in the soil but the nitrogen concentration was at near the

limit of detection (0.01 mg/) Therefore the effects of

nitrogen content (at three levels) were tested. Biological

degradation was confirmed by comparing samples with

controls, and was the main contributor to the decrease of

phenol concentrations. The result showed no differences

among these treatments as presented in Figures 5-8 and 5-9,

indicating that at least part of the phenol was assimilated

for energy but not for growth.


5.4.2 Single Compound Biodegradation.


 Batch biodegradation experiments for phenolic compounds

were performed. Treatments with indigenous soil bacteria

and amended with municipal wastewater sludge were included.

The apparent degradation rate constants were calculated

based on first order reaction kinetics.

 Phenol degraded rather quickly, with average half-lives

ranging from 9 hours for the C =5ppm group to 15 hours for
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