Use of β-D-galactosidase and β-D-glucuronidase activities for quantitative detection of total and fecal coliforms in wastewater

Two enzymatic methods based on the measurement of the beta -D-galactosidase activity of total coliforms and the beta -D-glucuronidase activity of Escherichia coli were used to assess coliform levels in wastewater alongside traditional culture-based techniques, which can be biased by the aggregation of bacteria or their attachment to particles. Enzymatic methods were precise (i.e., coefficients of variation were 9%-15%), rapid (response in 20 min), and correlated well (in log units) with traditional techniques for raw and treated sewage (r(2) > 0.75). They were used for rapid assessment of coliform removal efficiency in two different wastewater treatments. These methods could be useful for the estimation of the abundance of coliforms in domestic sewage and their removal by wastewater treatment processes.