AWWA QTC97106

The City of Houston, Texas, consumes more than 360 million gallons of water each day. To provide a higher quality of treated surface water and to be prepared for the proposed Stage I and II Disinfectant/Disinfection Byproducts (D/DBP) Rule and the Enhanced Surface Water Treatment Rule, a study was conducted at the City's East Water Purification Plant to determine possible options for reducing DBP formation in treated surface water. The study was conducted in three separate phases. First, a series of bench-scale tests were performed by varying enhanced coagulation parameters, pH, chemical dosages, and mixing velocities. Second, modifications were made to the chlorine and ammonia dosages, and various pre and post coagulation chloramination points were tried. Third, water produced using membrane technology was blended with water produced using existing conventional treatment methods. Additionally, apparent molecular weight (AMW) tests were performed on natural organic matter in plant forebay water to determine the relative contribution of the higher and lower molecular weight fractions to DBP formation.