UV disinfection costs for inactivating Cryptosporidium

Recent findings that Cryptosporidium inactivation occurs at technically and economically feasible ultraviolet (UV) doses have generated a wellspring o f interest in UV disinfection for drinking water. Many utilities are consid ering UV disinfection as a means to meet future regulatory requirements at their existing facilities. Most utilities evaluating UV disinfection will b e retrofitting existing treatment plants. In this article, capital, operati ons and maintenance, and total annualized costs were estimated for retrofit ting existing facilities with UV disinfection after the filters and before the clearwell. Cost estimates were developed for a UV dose of 40 mJ/cm(2), which would ensure at least 2-log inactivation of Cryptosporidium, based on current research, and for a range of flows and filtered water qualities. T he cost estimates presented indicate that UV disinfection is a relatively i nexpensive method to achieve a high level of Cryptosporidium inactivation. As expected, annualized costs increased as system size decreased, although the costs were lower than those of other technologies providing similar lev els of Cryptosporidium removal/inactivation.