AWWA JAW59515

The presence of the parasite Cryptosporidium in watersheds poses a serious health problem and a challenge to water utilities. Several waterborne outbreaks of cryptosporidiosis, the disease caused by the parasite, have occurred world-wide and, in 1993 an outbreak in Milwaukee, Wisconsin involved an estimated 403,000 people. The oocyst associated with Cryptosporidium is extremely resistant to disinfection through chlorination. If water utilities hope to gain or maintain a US Environmental Protection Agency grant of a filtration avoidance determination, they must demonstrate that their watersheds are being adequately protected from Cryptosporidium. A major source of the parasite has been traced to beef and dairy farms where manure from infected animals is spread across fields and eventually drains into surface water supplies. In this article, the author reviews the diverse and scattered literature related to the methodologies of managing manure to accomplish oocyst inactivation. The article specifically explores slurry storage, anaerobic digestion, and composting and the two main factors affecting oocyst survival, which are temperature and ammonia levels. An Expanded Summary in this issue offers a condensed review of the literature; a full discussion of the literature can be found online at www.awwa.org/communications/e-journal/index-past issues/2004/February. Includes 3 references.