Pulp wastewater treatment method in paper mill
Step 1: Send the pulp wastewater to the primary filter, and add a flocculant to the first filter to reduce the concentration of the pulp wastewater.
Step 2: The sewage in step 1 is introduced into the sewage filtering equipment of the wedge filter for filtration to realize the refiltration and separation of the pulp sewage. The sedimented pulp in step 1 is fished out by the fishing net.
Step 3: The sewage separated in step 2 is introduced into the aeration tank for aeration. At the same time, add hemp or man-made fibers in the aeration tank, and then manually pull out the floating hemp or man-made fibers.
Step 4: The aerated sewage in step 3 is sequentially introduced into the aerobic anaerobic bioreactor for aerobic anaerobic treatment.
Step 5: Put the wastewater after the anaerobic treatment in Step 4 into an open-air drying tank for evaporation and drying. There are multiple open-air drying ponds, and evaporation mirrors are installed around the open-air drying ponds to reflect sunlight into the wastewater and improve the evaporation efficiency of the wastewater.
Biochemical treatment is a key part of waste paper and papermaking wastewater treatment. The "anaerobic + aerobic" process has the advantages of impact load resistance, high COD removal rate, low power consumption, and low operating cost, and has been widely used.
Usually, hydrolysis acidification or complete anaerobic reactors (UASB, IC, PAFR, etc.) are used for anaerobic treatment.
According to the concentration of biochemical influent, we choose to control the anaerobic stage in the hydrolysis acidification stage or the complete anaerobic stage. When the CODcr of the biochemical feed water is greater than 800 mg/L, a complete anaerobic reactor is recommended.