Low-cost trihalomethane reduction through air stripping
It has been found that addition of chlorine as a disinfectant in the water treatment process leads to the formation of disinfection byproducts (DBPs) which have been associated with cancer in humans. The DBPs of much concern and which are the focus of this study are the trihalomethanes (THMs). Since their discovery, efforts have been made to prevent THM formation. This study focuses on removal of THMs after their formation rather than at preventing their formation. Because THMs are known to be very volatile, aeration using a low-cost packed air stripping column was thought to be an ideal method for removing THMs and was at the center of this study. ^ One factor that made this study unique was the ability of this air stripping column to reduce THM concentration from a very small initial THM concentration of about 37 ppb. Results showed that, although it is considerably more difficult to remove THMs when initial concentrations are low, this method was effective at removing over 70% of total THMs. This method was especially effective when air to water ratios were above 50:1. ^ Other studies have been conducted using this same principal, but this study was unique because of the low capital and operating costs involved. This alone makes results of this study highly attractive to smaller utilities that are, like larger utilities, regulated by federal law to meet the 80 part per billion (ppb) limit for total THM concentration. Total cost for this removal method was found to be 2.1 cents per thousand gallons of water treated.^
Rodriguez, Ruben, "Low-cost trihalomethane reduction through air stripping" (2007). ETD Collection for University of Texas, El Paso. AAI1444117.