Treatment of pulp wastewater in paper mill
Step 1: feed the pulp sewage into the primary filter, and add flocculant to the first filter to reduce the concentration of the pulp sewage.
Step 2: the sewage in step 1 is introduced into the sewage filtering equipment of the wedge wire filter for filtration, so as to realize their filtration and separation of the pulp sewage, and the precipitated pulp in step 1 is fished out by the fishing net.
Step 3: introduce the sewage separated in step 2 into the aeration tank for aeration. At the same time, hemp or man-made fiber is added to the aeration tank, and then the floating hemp or man-made fiber is pulled out manually.
Step 4: the aerated sewage in step 3 is successively introduced into the aerobic anaerobic bioreactor for aerobic anaerobic treatment.
Step 5: put the anaerobic treated wastewater in step 4 into the outdoor drying tank for evaporation drying. There are many open-air drying pools, and evaporation mirrors are installed around the open-air drying pools to reflect sunlight into the waste water, so as to improve the evaporation efficiency of the waste water.
Biochemical treatment is the key part of waste paper and papermaking wastewater treatment. “Anaerobic + aerobic” process has been widely used because of its advantages of shock load resistance, high COD removal rate, low power consumption, and low operation cost.
Generally, hydrolytic 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 hydrolytic acidification stage or the completely anaerobic stage. When the CODcr of biochemical influent is more than 800 mg / L, a complete anaerobic reactor is recommended.