Abstract |
A random selection of 186 water utilities was used for this study in which raw and finished water samples were collected from each facility five times throughout a year and analyzed for iron and aluminum by atomic absorption techniques. The water samples were categorized by the supply source (ground, surface, or a combination of both), the type of water (raw, finished, or untreated distribution samples), and the type of coagulation used in the treatment process (aluminum sulfate, ferric chloride, other coagulants such as cationic polymers, or no coagulant). The samples were also categorized according to the 10 US Environmental Protection Agency regions and 4 population categories. The results indicate that aluminum is more likely to exist in surface waters than in groundwaters and that there is a 40-50 percent chance that alum coagulation increases the aluminum concentration of finished water above its original concentration in the raw water. |