AWWA JAW3790

Blooming species are difficult to eradicate from water supply systems and may pass through distribution lines intact at concentrations of several thousand cells per millilitre, possible affecting the palatability of finished water and posing potential health hazards to consumers. Approximately 125 samples representative of spring and early summer conditions in five water supply systems revealed that algae may attain densities of up to 490,000 cells/mL in reservoirs unprotected by free chlorine residuals. Free chlorine was found to be strongly algicidal to Chlorella vulgaris, the dominant alga of all systems examined. Includes 32 references, tables, figures.