The food industry, with its wide range of raw materials and its wide variety of products utilizes a great range of water quantities with very different treatment problems and quality standards. In the processing of food products the main pollutants are (1) solid materials floating on the wastewater, such as leaves, skins, minced meat, poultry feathers, etc.; (2) substances suspended in the wastewater such as grease, protein, starch, colloidal substances, etc.; 3) acids, alkalis, salts, sugars, etc. dissolved in the wastewater; (4) silt and other organic matter associated with the raw materials, etc.; (5) pathogenic bacteria. A majority of the toxicity is usually not a problem. Rather, it is eutrophication of natural water bodies that causes the death of aquatic animals and fish. It also produces malodorous odors from the organic matter deposited on the water bottom. On the plus side, some of the potential pollutants can be recovered and used as valuable by products. For example; waste sludge as fertilizer and biogas.
Winner uses the usual three types of modern wastewater treatment approaches: physical treatment, chemical treatment, and biochemical treatment. Physical treatment methods include precipitation, filtration, centrifugal separation, and flotation. Chemical treatment methods include coagulation, neutralization, redox, electrolysis, extraction, blow-off, absorption method, electrodialysis, and reverse osmosis. Biochemical treatment methods may include use of activated sludge, biofilm, oxidation pond/s, and land treatment. There are also new technologies such as enzymatic degradation, use of hyperactive degrading bacteria, and use of things like ultrasonic technology, magnetic separation, supercritical water oxidation, electrode biofilm, and others.