Balancing Disinfection By-Product Control with Taste and Odor Control: Comparison of Ultraviolet Oxidation, Granular Activated Carbon and Conventional Treatment

摘要

The Texarkana Water Utilities (TWU)/International Paper (IP) Water Treatment Plant (WTP) treats water from Wright Patman Lake. It is a conventional surface water treatment plant utilizing prechlorination to control iron and manganese, as well as provide primary disinfection. The source water organic carbon levels are high (average is 8 to 12 parts per million (ppm), but can be greater than 20 ppm), which historically has led to disinfection by-product (DBP) concentrations exceeding USEPA Maximum Contaminant Levels (MCL). In addition, taste and odor events occur periodically as a result of algae growth in the source water. Finished water sample results have revealed geosmin as high as 2,400 nanograms/Liter (ng/L) and methylisoborneol (MIB) up to 100 ng/L. A combination of options to control disinfection byproducts and taste and odor compounds while providing adequate disinfection were evaluated, including alternative technologies like advanced oxidation utilizing ultraviolet light with hydrogen peroxide and granular activated carbon adsorption, as well as conventional options, such as the addition of permanganate for oxidation at the head of the plant to eliminate prechlorination. The advantages and disadvantages of the potential treatment process changes are presented along with construction and operation and maintenance costs to compare the various options evaluated.