How to Treat Papermaking Wastewater?

Papermaking wastewater mainly refers to the liquid that exceeds the standard produced by the pulp-and-paper industry.

The Process of Wastewater Treatment: Primary Filtration - Secondary Filtration - Cooling - Precision Filtration - Acid-base Neutralization - Anaerobic Treatment and Aeration - Discharge

1. Primary Filtration 

The effluent is discharged into the primary filter tank where most of the suspended solids are filtered out with 3 layers of filter mesh with decreasing filtration precision from top to bottom.

2. Secondary Filtration

The secondary filter tank is used to filter out all the suspended solids remaining in the effluent. There equipped a stirring shaft with three sets of strainers installed symmetrically on both sides of it.

3. Cooling

The effluent after secondary filtration is then piped into the cooling tower, where the effluent is cooled down to 50℃.

4. Precision Filtration

The effluent is drained from the cooling tower to the flocculation pool for sedimentation. Here the sediment is produced an hour after the flocculating agent is added. Then, the security filters are adopted to remove the sediment. It should be noted that before discharged into the neutralization pool, the effluent must be filtered. So how to select a suitable filter cartridge in this crucial step? Hongtek Melt Blown Cartridge and High Flow Filter Cartridge could be an excellent choice. And the most commonly used specifications are shown as below: 

High Flow Filter Cartridge, 40" OD 6.5", 5 micron high quality pleated high flow cartridge filters

PP Melt Blown Cartridge with Double Open End. In Length of 40 inches,  Inside Diameter of 28mm and Outside Diameter 63mm.

5. Acid-base Neutralization

Neutralizing the PH value of effluent in the neutralization pool to 7 by adding the neutralizing agent.

6. Anaerobic Treatment

After the effluent is neutralized, an anaerobic tank is used for anaerobic treatment.

7. Aeration

In this step, the effluent is discharged into the aeration tank, where the oxygen is supplied to the effluent in the form of air by special aeration equipment, such as blast blower and jet aerator. 

8. Advanced Treatment

In the process of advanced treatment, a shallow air flotation machine is used to remove the specific wastewater constituents that cannot be removed by secondary treatment, such as nitrogen, phosphorus, additional suspended solids, refractory organics or dissolved solids. 

9. Inspection

Finally, the treated effluent is allowed to flow into the discharge pool...But wait! The end is not yet! The water may not be discharged until measuring up to a given standard!