The waste water of the food industry is characterized by high content of organic substances and suspended solids, easy to be spoiled, and generally no major toxicity. The hazard is mainly to make the water eutrophication, causing the death of aquatic animals and fish, causing the organic matter deposited on the bottom to produce odor, deteriorating water quality and polluting the environment.
In addition to proper pre-treatment according to the characteristics of water quality, wastewater treatment in food industry should generally adopt biological treatment with self-cleaning filter. If the effluent water quality is very high or because the organic content of the wastewater is high, a two-stage aeration tank or a two-stage biological filter or a multi-stage biological turntable may be used. Alternatively, two biological treatment devices may be used in combination, or an anaerobic-aerobic tandem biological treatment system may be employed.