Paper production wastewater treatment procedure

Paper production wastewater treatment procedure
Black liquor and intermediate wastewater: alkali recovery, acid precipitation methodology, LB-1 alkali precipitation technique, membrane separation strategy, flocculation sedimentation, biofilm methodology, anaerobic biological treatment, mesh microfiltration, air flotation, advanced oxidation.
White water: filtration, air flotation, sedimentation, screening.
The concentration of SS and COD in waste paper papermaking wastewater is relatively substantial, and COD is composed of two components: insoluble COD and soluble COD. Non soluble COD typically constitutes the majority of the total COD composition. When SS is eliminated from the wastewater, the vast majority of insoluble COD is also eliminated. Therefore, the primary challenge to be addressed in the treatment of waste paper and papermaking wastewater is the elimination of SS and COD. There are primarily the following methodologies:
(1) Air flotation or sedimentation methodology. By utilizing air flotation or sedimentation methodologies and incorporating coagulants, the majority of SS can be eliminated, while the majority of insoluble COD and some dissolved COD and BOD5 can be eliminated.
(2) Conjoining physical and biochemical treatments. For large and medium-sized paper making enterprises with low wastewater discharge and high COD content, it is challenging to attain the national first level discharge standards through single-stage air flotation or sedimentation physicochemical methods, as soluble COD and BOD5 primarily necessitate being effectively eliminated through biochemical methods. Typically, physicochemical and biochemical treatment methodologies are employed.
(3) Sludge disposal and comprehensive utilization. The loss of pulp during the papermaking process is inevitable. There are two advantages to performing well in recycling the waste pulp that flows into the wastewater: first, the recycled pulp can be reused for papermaking or sold as raw materials for low-grade paper, generating direct economic benefits; The second is to reduce the load of wastewater treatment and minimize the consumption of chemicals.