While potato starch has been an item of commerce for many years, traditional processing methods have incurred large volumes of high BOD effluents. The research summarized by this report has lead to a modified process which upgrades the soluble components formerly discarded in the effluent to animal feed materials in an economical manner. The process developed starts by grinding and sieving as in the traditional process with the exception that recycled juice rather than fresh water is used to flush the starch granules from the pulp in the sieving operation. The pulp is pressed and dried as in traditional processes. The starch is separated from the juice and refined by an 'elutriation' type liquid cyclone and a basket centrifuge. Water - at the rate of one kg per four kg of input potatoes - is introduced at the basket centrifuge and flows in a counter-current manner through the cyclone system. Excess juice is heated to precipitate the heat coagulable protein. The protein is centrifuged from the juice and spray dried; the deproteinated juice is concentrated to a molasses-like feed material by reverse osmosis and multiple effect evaporation.

Prepared for U.S. Environmental Protection Agency, Office of Research and Development, Industrial Environmental Research Laboratory, Cincinnati, Ohio, under Grant no. R-8030712. Includes bibliographical references (pages 28-29).