Paint wastewater treatment
The removal efficiency of CODCr was about 30%, and then PAC and PAM were used to coagulate and precipitate. The two-step process was carried out by using Fenton reagent (H2O2 + FeSO4) Treatment, CODCr total removal rate can reach 60% to 80%, from 3000 ~ 20000mg / L down to 1200 ~ 4000mg / L. The effluent is drained into a mixed wastewater.
Paint wastewater is mainly from the wet spray room with water washing spray room operating area air, air paint and organic solvents are transferred to the formation of water spray paint. Wastewater contains a large amount of paint particles, the water quality used by the paint (nitro paint, amino paint, alkyd paint and epoxy paint), solvents (such as ethanol, acetone, esters, benzene) and additives set.
Paint Wastewater - "Regulating Pool -" Coagulation - "Air Float -" Biochemical Pool - "Sedimentation Pond -" Water
In the cathodic electrophoresis wastewater contains a large number of high molecular organic compounds, CODCr up to 20000mg / L, also contains a large number of electrophoretic slag, these substances in the water was a small suspended matter or negative charge colloidal. The appropriate cationic polyacrylamide (PAM) and polyaluminium chloride (PAC) were added as coagulants, and the pollutants in the wastewater were quickly removed by the adsorption bridging action of the flocculant. Electrophoretic waste liquid in the pretreatment requires pH between 11 ~ 12, a better precipitation effect. The effluent CODCr after the reaction was around 2000 mg / L.
The degreasing waste liquid is subjected to demulsification pretreatment by acidification, adding the inorganic acid to the degreasing waste liquid to adjust the pH to 2 to 3, so that the fatty acid in the emulsifier is soaped with fatty acids, and the higher fatty acids are insoluble in water and dissolve Oil, so that degreasing waste liquid demulsification oil. In addition, after adding acid in the degreasing waste in the anionic surfactant in acid solution easily decomposed and lose stability, lost the original lipophilic and hydrophilic balance, so as to achieve demulsification. After the pretreatment, CODCr decreased from 2500 ~ 4000mg / L to 1500 ~ 2400mg / L, the removal rate was about 40%, while the oil content decreased from 300 ~ 950 mg / L to 50 ~ 70 mg / L, the removal rate was as high as 90% ~ 95%.
