Abstract: An improved method for recovering and processing waste water solids into animal foodstuff wherein bentonite is added to waste water comprising oils, fatty acids, grease, or the like. The pH of the waste water is regulated, bentonite and a polymer are added, and the treated waste water is transferred into an air flotation device. A float blanket containing solids and water forms readily and is removed and transferred to a drying apparatus. The float material, or sludge, typically contains between 2-10% solids and is ready to be introduced into the drying apparatus without further modification. However, the sludge is usually belt compressed to obtain a solids concentration between 20-40% to assist in handling and drying. The drying apparatus employed contains two zones. In the first zone, air enters the dryer at a very high temperature where it encounters the sludge also being introduced. As the sludge comes into contact wth the hot air, it is flash dried.

Abstract: Method for removing suspended solids from a stream of waste water for subsequent use as an animal feed, wherein bentonite and an anionic polymer are added to the waste water which is maintained within a predetermined pH range. No metallic salts or other materials unacceptable as food additives are added to the waste water stream to facilitate flocculation of the bentonite and suspended solids. The pH range, maintained from 3.5 to 9.0 and optimally from 4.0 to 5.0, facilitates the coagulation of the suspended solids without the use of the metallic salts or other such additives. Microscopic air bubbles are used to float the flocculated bentonite and solids to the surface. In some cases the materials may be floated by gravity forces alone without the use of air bubbles. These floated materials are removed by skimmers or other top-floating solids removing apparatus commonly known in the industry and rendered into animal feed products.