Synthetic leather wastewater mainly comes from the wastewater discharged by the production process and the support facilities of synthetic leather as well as the domestic sewage of the employees of the enterprise, which mainly includes five kinds of wastewater:
Wastewater generated during the production process, post-processing water mixed with wastewater, cleaning wastewater from the DMF recycle system, cooling circulation drainage and domestic sewage.

Water Quality Characteristics
The main pollution agents in the wastewater are COD, DMF, SS and NH3-N, the wastewater has low biochemical quality and bad biodegradability, and it has certain chroma. Of which, the DMF (dimethyl formamide) contained in the wastewater is an organic solvent which can stimulate and harm human eyes and cause liver dysfunction. If the DMF wastewater is directly discharged, it will cause increase of biochemical oxygen consumption and nitrogen content, which tend to deteriorate the water quality quickly; in addition, because it has stable chemical property and hard to degrade, it is very harmful to the environment, and effective treatment should be conducted to reach the standard for discharge.

Thought for Treatment
After being collected from the wastewater pipe network, the synthetic leather wastewater first enters the rotary mechanic grille and sand-water separator to have the suspended matters, floating objects, oil and sand in the wastewater removed, and then it enters the wastewater regulation tank, where homogeneity and volume balance is conducted to the wastewater. The production process has adopted the international advanced technology integration to remove multiple pollutants such as COD, BOD, SS, DMF, chroma, ammonia nitrogen, phosphates, oil and grease as well as the anionic surfactants at the same time; for the effluent, the ozone strong oxidation + activated carbon adsorption technology is conducted to further treat DMF to stabilize the effluent and make it reach the standard for discharge.

Typical Treatment Process
In accordance with the water quality and discharge characteristics of the synthetic leather wastewater, a process combining pretreatment + biochemical treatment + physicochemical treatment is adopted.