For example, fruits, vegetables, meat, seafood, and so on, the wastewater from general food factories contains some solid substances suspended in the wastewater.

 

1. Processing vegetable products produces vegetable leaves, processing fruits produces fruit peels, as well as minced meat, animal feathers, and so on;

 

2. Suspended substances contain a certain amount of oil, protein, starch, gelatinous substances, etc;

 

3. Some raw materials may also carry mud and sand, as well as dissolved substances such as acids, salts, sugars, and alkalis in wastewater;

 

4. Food factory wastewater is a type of industrial wastewater, characterized by high levels of several substances and suspended solids, making it difficult to store and prone to decay. Although it is not highly toxic, it contains pathogenic microorganisms. If this type of sewage is directly discharged into rivers without treatment, it will lead to the extinction of aquatic organisms such as fish and shrimp, causing several substances deposited at the bottom of the water to produce a foul odor, deteriorating water quality, and causing serious pollution to the environment. For the treatment of wastewater from food factories, physical pretreatment methods can be selected based on the characteristics of water quality, while biological process treatment methods are more commonly used.

 

2、 Food processing wastewater mainly comes from three production stages.

 

1. Raw material cleaning section. A large amount of sand, debris, leaves, skin, scales, meat, feathers, hair, etc. enter the wastewater, causing a large amount of suspended solids in the wastewater.

 

2. Production section. Many components in the raw materials cannot be fully utilized during the processing, and the unused parts enter the wastewater, resulting in a large amount of impurities in the wastewater.

 

3. Forming section. In order to increase the color, aroma, and taste of food and extend its shelf life, various food additives are used, and some of them are lost into the wastewater, making the chemical composition of the wastewater complex.

 

2、 Main components of the equipment

 

1. Oil separation and sedimentation of sewage - an oil separation tank is a treatment structure that uses the difference in specific gravity between oil and water to separate and remove suspended oil particles with larger sizes from sewage. The oily surface in the wastewater is collected by the oil collection pipe and discharged. The suspended solids and other impurities that settle in the oil separation tank accumulate in the sludge hopper at the bottom of the tank and are regularly removed by the environmental sanitation department. The wastewater that has undergone oil separation treatment overflows into the drainage channel and is discharged outside the pool for subsequent treatment.

 

2. Regulation of sewage - Due to the large fluctuations in water quality and quantity of food processing wastewater, it is necessary to strengthen regulation to stabilize the water quality and quantity of sewage, in order to ensure the effectiveness of subsequent biochemical treatment.

 

3. Hydrolysis acidification reaction - Due to the low concentration of this type of wastewater, anaerobic digestion treatment is not necessary, and only hydrolysis acidification process is needed.

 

The active microorganisms in the hydrolysis and acidification process are hydrolysis microorganisms and acid producing bacteria, both of which operate under anaerobic conditions and do not require dynamic aeration. Therefore, the hydrolysis and acidification tank can partially degrade certain substances without energy consumption, reducing operating costs; At the same time, acid hydrolyzing bacteria can convert difficult to degrade large molecules into easily degradable small molecules, improving the treatment efficiency of subsequent aerobic treatment units. The use of hydrolysis acidification process can greatly shorten the time required for aerobic biochemistry; After simultaneous treatment, the effluent quality is better, which not only saves investment and operating costs, but also improves environmental benefits.