Trihalomethane Formation in High‐Bromide Lake Galilee Water

A study was conducted of trihalomethane (THM) levels in Israel's national water supply system, which is composed of open channels, open operational reservoirs, and a long, closed conduit. The system derives its water from Lake Galilee. Because of the high bromide concentration in the lake, bromoform is the dominant THM formed. Significant volatilization of THMs was observed in the open channels, and the major production of THMs occurred in the closed conduit. Laboratory investigations showed the formation of relatively high concentrations of THMs at chlorine dosages (2-3 mg/L) and contact times (18 h) similar to those used in the system. The THM formation potential of water from an operational reservoir was significantly lower than that of raw lake water.