Introduction of pollutants in leather industry

Hello, the leather factory has a great impact on the environment, mainly from the following aspects:

1. Tanning production generally includes: preparation section, tanning section and finishing section;

2. Production technology:

The rawhide is finished by washing, soaking, unhairing, liming, removing meat, cleaning, washing, softening, washing, pickling, chrome tanning, cutting evenly, neutralizing, dyeing, oiling and finishing.

Pollution sources and pollution factors:

Tannery wastewater (COD, BOD5, SS, sulfide, chloride ion, trivalent chromium, phenol, PH, chromaticity, animal and vegetable oil, etc. )

Air pollution (TSP, PM 10, SO2, NOX, NH3, H2S, odor, etc. )

Solid waste (waste wool, meat film, broken skin, scraps, leather scraps, sewage station sludge, boiler slag)

Noise (equipment noise)

In addition to boiler flue gas, tannery waste gas also includes volatile organic solvents used in production and malodorous pollutants generated in storage, production and sewage stations of hides.

The main sources of wastewater: during the production and processing of hides, a large amount of protein and fat enter into wastewater and waste residue; A large number of chemical raw materials are used, such as acid, alkali, salt, sodium sulfide, lime, chrome tanning agent, dye, etc. , has entered the waste water. Tanning wastewater mainly comes from preparation, tanning and wet processing sections, in which the wastewater discharge and pollution load of preparation section before tanning account for 70% of the total tanning wastewater; Tanning stage and wet processing stage account for about 8% and 20% of wastewater respectively;

Tannery wastewater has strong alkalinity and deep chroma, and contains inorganic substances such as protein, fat, dye, chromium, sulfide and chloride, which belongs to toxic and harmful wastewater. Among them, the chromium removal process and the sulfide in the waste liquid of lime-alkali hair removal are seriously exceeding the standard, which is the focus of wastewater treatment in leather industry.