With the improvement of people’s quality of life, the demand for meat products has gradually increased, and the proportion of wastewater discharged from slaughterhouses and meat joint factories in industrial wastewater has also gradually increased.
Slaughter wastewater mainly comes from:
- Animal manure flushing water discharged from ante-mortem feedlots
- Ground flushing water containing blood and livestock manure discharged from slaughterhouse
- High temperature water containing a lot of pig hair discharged during scalding
- Dissection of wastewater containing gastrointestinal contents from the workshop
- Grease wastewater discharged from refinery workshop
In addition, there are cooling water from the refrigerating machine room and domestic sewage discharged from the workshop sanitary equipment, boilers, office buildings, etc.
The slaughtering wastewater contains a large amount of pollutants such as blood, fur, minced meat, internal organs, undigested food and feces. The concentration of suspended solids is very high. waste water.
Generally, it does not contain heavy metals and toxic chemicals. The wastewater is rich in protein and oil, and has a high organic content. The nutrients are nitrogen and phosphorus. Among them, nitrogen exists in the form of organic matter and ammonia nitrogen, and phosphorus exists in the form of phosphate. Has good biochemical properties.
In addition, due to the differences in the production process, processing objects and management level of the slaughterhouse, the discontinuity of production time and the obvious seasonality of production, resulting in a wide range of changes in the quantity and quality of wastewater, the general time-to-time variation coefficient can reach 2.0.
The waste water is mainly duck slaughtering waste water and domestic sewage, the discharge amount is 1000m3/d, and the influent water quality is:
CODCr1600～1800mg/L, BOD5: 600～800mg/L, SS: 700～900mg/L, animal oil: 60～70 mg/L, pH: 7～8.
The pretreatment process is that the wastewater passes through the wedge wire screen grid to intercept the larger pollutants and sandy substances in the wastewater, and enters the oil separation adjustment tank to buffer and balance the water quality and quantity of the wastewater to a certain extent, and remove part of the grease.
The macromolecular substances are then hydrolyzed.
Enter the high-efficiency coagulation and air flotation system integrating coagulation reaction and air flotation separation technology to further remove fine suspended solids and grease.