feasibility of applying in-situ biodegradation techniques to

groundwater remedial problems.


 6.2 Conclusions


 The following conclusions were drawn from this research

project:

 1. The sorption behavior of phenol, 2,4-DCP and PCP

was non-linear on soils with negligible organic carbon

contents.

 2. Phenol will not be retarded once introduced to

groundwater systems, while higher chlorinated phenolic

compounds exhibited higher retardation factors.

 3. PCP desorption showed hysteresis but not phenol and

2,4-DCP desorptions.

 4. On soils with negligible organic carbon content the

phenolic compounds exhibited competitive sorption.

 5. Extra ammonia nitrogen did not interfere with

phenol biodegradation.

 6. All three phenolic compounds were biodegradable,

with the half-life of phenol in hours, PCP took a much

longer time to degrade.

 7. PCP alone could not support enough bacterial growth

to outpace the decay.

 8. Initial bacterial populations influenced both the

extent and rate of degradation of PCP.

 9. Periodic addition of fresh bacterial sources will

be necessary when PCP is the only carbon and energy source.