ASSESSING PLANT PERFORMANCE USING MPA

Concentration of microbiota and total particulates in raw and finished water samples from 55 coventional treatment plants was compared. Anal yses included (1) enumeration and identification of the microbiota, (2 ) direct measurement of the pellet volume of total particulates after laboratory centrifugation, (3) total particle counts, and (4) Giardia and Cryptosporidium detection. Organism reduction based on microscopic particulate analysis in the raw and finished waters ranged from -0.8 to 6.0 log. There was a significant correlation between reduction valu es generated by organism counts, centrifugate pellet measurements, and particle counts. However, only organism reduction values remained con sistent regardless of influent turbidity or flocculent material presen t in the effluent. Because of low concentrations and intermittent occu rrence, counts of Giardia and Cryptosporidium did not accurately refle ct treatment plant performance.