With the expansion of the Tillamook Creamery, in Tillamook Oregon, to double or more its cheese production, the demand for milk presents an economic opportunity for the member dairies of the Tillamook County Creamery Association. Before area dairies can expand their herd size to increase milk production for the creamery, the problem of manure waste management and pollution control must be solved. This study considers the technical and economic feasibility of developing a centralized waste treatment and methane generation facility to treat manure generated by Tillamook County dairies. A computer program modeling animal waste anaerobic digester design served as the basis for generating cost and production estimates for several hypothetical scenarios assuming input data specific to the Tillamook situation. A follow up study was also made to determine the variability of the potential ultimate methane yield of manures from Tillamook dairies. This study indicates that the proposed system is technically feasible. The study estimates that a comprehensive treatment system could cost dairymen from $70 to $100 per cow per year to start, but the economic feasibility improves as more manure is treated and more dairies participate. A full scale system has the potential to break even economically from the sale of electricity produced by a 5 megawatt methane powered generator. With the marketing of treated solids as a high grade fertilizer the system could gross a return of $1 to $75 per cow per year, depending on the scenario. / Graduation date: 1992