How to Recycle The Precipitated Pulp In Paper Mill
The pretreatment of waste paper and papermaking wastewater is the premise to ensure that the system meets the standard, main purpose of pretreatment: Recover the fiber in wastewater and reduce the load of biochemical system.
In general, white water is recycled in the workshop, the pretreatment described in this paper is mainly the off-site treatment of mixed wastewater, mainly including pulp recovery, physical and chemical treatment.
The commonly used pulp recycling equipment includes inclined screen, gravity gravity self flow screen filter, common rotary filter, reverse tangential unidirectional flow rotary filter, etc., and the commonly used one is inclined screen.
We provide customized service for Johnson screen filter elements in pulp equipment of paper mill.
It is suggested to determine the hydraulic load and mesh number according to the test. In the absence of data, the recommended hydraulic load is 10-15 m3, and the wedge wire slot size is 150 microns – 180 microns.
The multi disc was originally used for white water treatment in the factory, and now the box board paper factory has used it to recover the fiber mixed with waste water outside the factory.
The operation cost of multi disc is low, it does not need to add medicine basically, the quality of recovered fiber is high, and the content of suspended substance in effluent is low (SS < 60mg / L)
The primary sedimentation tank can be omitted later, which has a broad application prospect.
It is worth the attention of designers that the pulp on the filter screen needs to be washed with clean water when it is removed, so there is a defect of wasting water resources.
Therefore, wedge wire screen filtration separation products have more advantages.
Pulp wastewater refers to the wastewater produced in the paper-making process. The direct discharge of this kind of wastewater will seriously affect the environment, and a large number of pulp will be left in the pulp wastewater, which has a high recycling value.
Therefore, the paper pulp wastewater often needs to be filtered before discharge, the internal paper pulp is filtered and collected, and recycled, so as to reduce environmental pollution and save production costs.
A method of pulp sewage treatment in paper mill
Step 1: pass the pulp sewage into the primary filter, and add flocculant to the primary filter to reduce the concentration of pulp sewage.
Step 2: the sewage in step 1 is led into the sewage filtration equipment of wedge wire filter for filtration, so as to realize the re filtration and separation of the pulp sewage, and the precipitated pulp in step 1 is salvaged out by the fishing net.
Step 3: introduce the sewage separated in step 2 into the aeration tank for aeration. At the same time, add hemp or artificial fiber in the aeration tank, and then manually pull out the floating hemp or artificial fiber.
Step 4: the aerated sewage in step 3 is successively introduced into the aerobic and anaerobic bioreactor for aerobic and anaerobic treatment.
Step 5: the waste water after anaerobic treatment in step 4 is put into the open air drying pool for evaporation and drying; there are multiple open air drying pools, and evaporation mirrors are installed around the open air drying pool, which reflect the 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 the advantages of impact load resistance, high COD removal rate, low power consumption and low operating cost, which is widely used.
Generally, 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. It is suggested to adopt the complete anaerobic reactor when the CODcr of biochemical influent is more than 800 mg / L.