Controlling Microbial Biota Transfer in the Garrison Diversion Unit

Abstract

The Garrison diversion unit is a canal system designed to distribute water from the Missouri River basin into western and eastern North Dakota. Canada has opposed the completion of the Garrison diversion unit because of a concern that the water sent to eastern North Dakota may degrade Canadian fisheries when it reaches Hudson Bay. To address this concern, a research project was done to evaluate the use of three different disinfection processes to inactivate harmful microorganisms in Garrison diversion unit water. The processes considered were chlorination, ozonation, and ultraviolet light. The objective was to identify a cost-effective means for inactivating bacteria and viruses that cannot be efficiently removed by broad-brush physical processes such as direct filtration or screening. The main criteria used to evaluate the three disinfection processes were reliability, cost, and potential adverse effects. The results indicated that chlorination was the most reliable and least expensive process but that ozone had fewer potential adverse effects. Ozone would also be a reliable process if the water were filtered before disinfection.