AWWA JAW26054

An independent assessment of streaming current detectors (SCDs) was carried out, including laboratory studies, a survey of SCD users, and on-site studies at water treatment plants. In accordance with theory, streaming current was found to be proportional to zeta potential, although a reading offset was observed. Users rated the SCD highly in most respects. The most commonly reported difficulty was clogging of the instrument or of sample lines. An analysis of periods before and after SCD installation at 10 treatment plants showed significant reductions in chemical expenses, particularly during times of changing raw water conditions. Water quality was not significantly improved, but this may have been because plant flows had increased between the periods being compared. Practical aspects of SCD use are discussed. Includes 17 references, tables, figures, photos.