The research was initiated to determine the applicability and limitations of the dehydrogenase test for the measurement of active biomass in biological wastewater treatment process. Pure culture with E. coli and/or heterogeneous culture batch studies were conducted on a variety of substrates including glucose, galactose, sucrose, alanine, acetic acid, and selected industrial wastewaters. Also conducted are continuous aerobic or anaerobic culture studies with and without solids recycle. Dehydrogenase activity was monitored along with other parameters including plate count, Coulter Counter enumeration, adenosine triphosphate (ATP), and suspended solids to provide comparative and complementary information on the biomass concentration. Dehydrogenase activity was a very sensitive and accurate measure of active biomass throughout the growth phases especially during endogenous growth but showed limitations with the nutrient deficient cultures. The correlation between dehydrogenase activity and suspended solids was constant at varying retention times, or at all growth rates with or without solids recycle. The technique for dehydrogenase activity measurement is simple, less costly and gives more reliable and interpretable results.

"EPA-600/2-75-029"--Cover "September 1975"--Cover "School of Civil Engineering, Georgia Institute of Technology." "Grant No. R-800354 (17050 GAI), Program Element No. 1BB043." "Project Officer Ronald F. Lewis." "Wastewater Research Division Municipal Environmental Research Laboratory." Includes bibliographical references (pages 127-134).