EVALUATION OF A MODEL BIOFILM FOR THE RANKING OF BIOCIDE PERFORMANCE AGAINST SULFATE-REDUCING BACTERIA

A model artificial biofilm was developed and evaluated for ranking the performance of biocides for application in oil production pipelines. The biofilm consisted of an alginate gel matrix into which were incorp orated bacteria, scrapings from the inner surfaces of oil production p ipelines and some crude oil. The viability and sulphide-respiration ra tes of sulphate-reducing bacteria (SRB) within freshly-prepared artifi cial biofilm remained largely unchanged during a 2-week storage period . Furthermore, storage of the model biofilm did not alter the suscepti bility of the incorporated SRB to a biocide. These findings showed tha t artificial biofilm may be produced in advance of a biocide assessmen t study and stored for at least 2 weeks over the course of the study w ithout the model system undergoing changes which affected the relative performance of the biocides assessed. Artificial biofilms were found to be more resistant to biocides than planktonic bacteria and the addi tion of oil pipeline scrapings and crude oil to the artificial biofilm was found to increase further the resistance of biofilm to biocides.