There are three general sources of paper effluent:
◆ Pulping fiber separation, bleaching and paper copying dilution, pressing, drying pulp and other processes to exclude a large number of fibers, inorganic salts and pigments and other pollutants with a high concentration of sewage that is black water.
◆ Washing and bleaching process produces a large amount of water containing high concentrations of lignin, cellulose and resin acid salts and other more difficult to biodegrade components in the middle section
◆ Paper machine discharge containing a large amount of fiber, filler and glue effluent, that is, white water
Features
◆ The Paper wastewater has high COD and suspended solids (SS) content and serious chromaticity.
◆ The concentration of SS and COD in Paper wastewater is high, while COD is composed of two parts: non-soluble COD and soluble COD.
Solution
Most of the wastewater can be reused after simple pretreatment to remove the sand and large suspended particles of the wastewater. The remaining part then passes through the grid, intercepting the short fibers in the sewage, short fibers can be recycled and reused, after the grid, the sewage enters the regulating tank, mainly to regulate the water quantity and quality of sewage, the front section of the regulating tank set mechanical agitation, and throw PAC and PAM, after coagulation of the sewage by lifting the pump to convey the high sedimentation tank, after sedimentation of the supernatant self-flow into the shallow pool air flotation for deep treatment, air flotation water may be sewage in The COD and BOD of air flotation may not reach the standard, so the bio-filter is set up after the air flotation to ensure that the sewage meets the standard discharge.