AN ASSAY FOR THE ENUMERATION OF TOTAL COLIFORMS AND ESCHERICHIA-COLI IN WATER AND WASTE-WATER

A novel pad was developed for identifying the end points of the beta-g alactosidase and beta-glucuronidase reactions used in determining tota l coliforms and Escherichia coli, respectively, in environmental sampl es. This method (ColiPAD(R)) was run in parallel with the standard mul tiple tube fermentation (MTF) technique on a total of 33 samples from the influent and treated effluent of two wastewater treatment plants a nd from a eutrophic lake. Differences in the number of positive tubes by the two methods were not significant for wastewater influent and la ke samples and were marginally significant for treated effluents. Regr ession analysis of log-transformed data yielded highly significant lin ear correlations between total coliforms by ColiPAD and total coliform s by the MTF method and between E. coli by ColiPAD and fecal coliforms by the MTF method.