PREDICTIVE MODEL FOR ESTIMATING THE EXTENT OF PETROLEUM HYDROCARBON BIODEGRADATION IN CONTAMINATED SOILS

A series of solid - and slurry-phase soil bioremediation experiments i nvolving different crude oils and refined petroleum products were perf ormed in order to investigate the factors which affect the maximum ext ent of total petroleum hydrocarbon (TPH) biodegradation. Utilizing a c omprehensive petroleum hydrocarbon characterization procedure involvin g group type separation analyses, boiling point distributions, and hyd rocarbon typing by field desorption mass spectroscopy, initial and fin al concentrations of specified hydrocarbon classes were determined in each of the seven bioremediation treatments. in this study, it was fou nd that the degree of TPH biodegradation was mainly affected by the ty pe of hydrocarbons in the contaminant matrix while the influence of ex perimental variables such as soil type, fertilizer concentrations, mic robial counts, and treatment type (slurry vs land-treatment) on the ov erall extent of TPH biodegradation appeared to be insignificant. Based on these findings, a predictive algorithm was developed to estimate t he extent of TPH biodegradation from the average reduction of 86 indiv idual hydrocarbon cf asses and their respective initial concentrations . Model predictions for gravimetric TPH removals were in close agreeme nt with analytical results from two independent laboratories.