Cationic Polyelectrolytes as Prime Coagulants in Natural‐Water Treatment

The objective of this study was to investigate parameters relating to the use of cationic polyelectrolytes as prime coagulants, and not as aids, in the treatment of natural waters. The experimental approach was divided into two parts. The first part consisted of a series of laboratory jar tests, using eight cationic polyelectrolytes, Potomac River water, and, for comparative purposes, natural water from four other area sources. The laboratory studies, which evaluated the effects of pH, hypochlorination, mixing rate, and color removal, were followed by full‐scale plant studies using a 3,000‐gph water purification unit, Potomac River water, and the most promising polyelectrolyte, as determined by the laboratory study.