AWWA WQTC62527

This study evaluates different treatment processes that have been shown to be effective for taste and odor control. The main processes that are used for taste and odor control are adsorption and oxidation. In the adsorption category are powdered activated carbon (PAC) and granular activated carbon (GAC). PAC requires low capital and operating costs at low dosages, but at the higher dosages required for PAC to perform adequately as a stand-alone process, the operating costs are much higher. If a convenient point for introducing PAC to give adequate contact time exists, a simple chemical feed system may be all that is necessary. GAC requires higher capital costs for the construction of contactors and is more costly per pound but is more effective and may have lower operating costs for handling tastes and odors that persist for more than a few days each year. GAC has limited ability at handling large spikes of taste and odor compounds because it can release these compounds once the spike has passed. In the oxidation category, ozone and advanced oxidation processes (AOP) are the most effective. Ozone at low dosages is capable of achieving moderate to high removal of taste and odor compounds. To achieve very high removals that are necessary to handle high influent concentrations, the ozone dose can be increased or hydrogen peroxide can be fed to convert the ozone to an AOP. Each of these responses will result in increased costs and may result in a compliance issue with the bromate standard. Use of ultraviolet light along with peroxide, another AOP, will not create the bromate issue, although the operating cost remains high. Includes table, figures.