The food industry includes meat processing, aquatic product processing, dairy processing, canning production, brewing, sugar production and many other industries, the quantity and quality of effluent vary greatly. The difference with other industrial sewage is that the sewage of food industry does not contain heavy metals, pesticides and other harmful substances, but its BOD, COD and so on will generally be on the high side. Since most of the raw materials used in the food industry are organic substances that can be digested by the human body, the biodegradability of wastewater from the food industry is generally good.

The main pollutants in sewage are:

Solid substances floating in sewage, such as vegetable leaves, fruit skins, minced meat, poultry feathers, etc.   Acids, alkalis, salts and sugars dissolved in sewage: silt and other organic matter carried by raw materials.

Food wastewater includes wastewater from the processing of alcohol, beer, monosodium glutamate, starch, lactose, citric acid, vegetables and various soft drinks, if the sewage is not treated in time, it will cause great pollution to the environment.

Characteristics of sewage

Food industry sewage is characterized by high organic matter and suspended matter content, easy to decay, generally no great toxicity, water quality and water volume changes with the seasons, high concentration of sewage. The main hazards are algal bloom, resulting in the death of aquatic animals and fish, causing the formation of odors, deterioration of water quality and pollution of the environment.

The treatment method

This kind of sewage is to adopt the air floatation anaerobic aerobic treatment as the main process, first the sewage is put into the oil-separating regulating tank, then the pump is put into the air floatation tank to remove most of the insoluble impurities and oils, then into the anaerobic aerobic biological treatment, biochemical treatment of the water to meet the three-grade standard into the urban sewage pipe network.