Evaluation of Pure Oxygen Systems at the Willamette Hatchery: Completion Report.

The oxygen transfer columns at the Williamette Hatchery are based on a design used by the Michigan Department of Natural Resources. The geometry and internal construction of the Mlilliamette Hatchery Oxygen Transfer Columns differ from the Michigan columns in several important ways. The performance of the columns was evaluated during May, 1990. The absorption efficiency of the 24 and 30 inch Williamette Hatchery Oxygen Transfer Columns ranged from 30 to 60%, which is comparable to published information on the Michigan columns. The performance of the 24 inch Williamette Hatchery Oxygen Transfer Columns was superior to either the 30 inch columns or the Michigan columns. The yearly oxygen demand for the Williamette Hatchery oxygen supplementation project is estimated to be 31,713 lb. Based on a oxygen purity of 99.6% and oxygen costs of $0.40/100 ft{sup 3}, increasing the absorption efficiency from 50 to 75% would decrease oxygen costs of the present project by only approximately $1018/year, which is small compared to the annual project cost. The pure oxygen system at Williamette Hatchery is designed for experimental purposes, therefore the existing system is adequate its intended use. While oxygen is not a major cost in the present experimental system, it will be much more critical in full-scale applications. It was necessary to build separate columns for the Williamette Oxygen Supplementation Project, but a centralized system may be more cost-effective in larger applications. There is considerable interest in the use of the Michigan type column in the Pacific Northwest and better definition of their operating characteristics or improvement in their performance would be useful to hatchery operations. In addition, there are a number of other oxygen transfer systems that may have potential in the Pacific Northwest