Potato wastes are one of the major pollutional sources in the State of Idaho. Even with primary treatment afforded by all processing plants, these wastes, in combination with other wastes, have resulted in fish kills and other pollution problems during periods of low flow in receiving streams. The potato processors are now faced with providing secondary treatment for their wastes and recognize that the cost of waste treatment must be considered to be part of the cost of doing business. The objective of the study is to conclude pilot plant studies on feasible methods of secondary treatment of potato processing wastes. Two specific methods are being investigated: an anaerobic lagoon followed by a surface-aerated, aerobic lagoon and an aerobic lagoon system. Due to late arrival of a surface-aerator the progress report covers only the first system - an anaerobic lagoon followed by a surface-aerated, aerobic lagoon.