Food industrial sewage mainly comes from raw material cleaning stage, production section, forming section. Because of the wide range of raw materials and products in the food industry, the water quality and quantity of raw water vary greatly. The main pollutants in wastewater are: solid substances floating in wastewater, such as vegetable leaves, peel, meat, etc.;oil, protein, starch, colloidal substances suspended in wastewater; acid, alkali, salt, sugar, etc., dissolved in wastewater; mud sand and other organic matter, etc.; pathogenic bacteria, etc. Food industry effluents are characterized by high organic and suspended matter content, perishable, and generally non-toxic.