Both phenol and PCP degraded faster in column

experiments than in batch experiments. The increase in

degradation rates for PCP were approximately five fold

faster than in batch experiments. With different added

bacteria concentrations, there were essentially no

differences in degradation rates. Two reasons could have

been contributing to these rate increases. The dynamic

flowing condition brought phenolic compounds as carbon

substrates to the bacteria and made these substrates

available for metabolism, while in static batch conditions

bacteria could only utilize the substrates immediately

surrounding them or the limited amount made available by

diffusion. It is widely believed that bacteria prefer

attachment situations to free floating situations because of

the energy requirements involved. In order to validate this

hypothesis, a DHA test was conducted on a column with clean

soil. Sub-samples were taken from the distilled water in

the column before and after an intentional mild stir. The

clear sub-samples taken before the stirring had an average

DHA value of 3.06x10-3 mg 02/I/day while the turbid sub-

samples taken after stirring had 1.30x10-2 mg 02/l/day. The

higher DHA value in the turbid sample indicate that the

hypothesis may be valid. The average standard error for

this test was 31.9%. Another contributing factor was that a

much larger quantity of soil was used in the column

experiments than in the batch experiments. Larger

populations of bacteria were therefore included initially.