Abstract: A method for purifying waste water high in carbohydrate while obtaining therefrom a high-protein feed product. The waste water is inoculated with yeast of the type that converts starch and sugars into more yeast. The pH is adjusted to desired levels, and then the inoculated waste is circulated and recirculated in conjunction with air in amounts that enhance the growth rate of the yeast. The purified liquid waste is then separated from moist solids, and a large proportion of the moist solids is harvested as feed material, while a smaller proportion is taken for use in recycle. The proportion to be recycled is sent to a treatment zone where the pH is lowered to approximately 3.5 and where antibiotics are added, the lowering of the pH and the antibiotics both serving to suppress a substantial portion of bacterial growth while enabling the yeast to grow. After a suitable dwell time, the treated material is used in the inoculating step as the inoculant.

Abstract: A method of producing an algae product and of purifying aqueous organic waste material to provide clean water. Starting algae and aqueous waste are admixed in sufficient amount to provide nutrients for the algae, which are grown in symbiotic relationship with aerobic bacteria present. The mixture is aerated and, if desired, carbon dioxide added, and is exposed to alternate periods of light (e.g., 1/2 second to ten seconds) and darkness (about ten times as long as the light period) to accelerate growth of the algae, harvesting the algae product to maintain the growth rate at a very high level. A device for effecting agitation and intermittent light exposure includes a reaction tank having a generally vertical wall in the form of a parabolic curve, injectors debouching into the bottom of the tank opposite the parabolic-curve wall and causing circulation so that injected and other material is forced rapidly upwardly, and a baffle transversely across the upper portion of the tank.