Paper industry production is divided into two main process stages, pulping and papermaking. Pulping is to separate the fibers from plant raw materials, make pulp, and then bleach it; papermaking is to dilute, shape, press, dry, and make paper from the pulp. Papermaking wastewater not only contains a large amount of papermaking raw materials (about 20% of the raw materials are lost with wastewater), but also contains a large amount of chemicals and other impurities, so if the papermaking wastewater is arbitrarily discharged without treatment, it will cause great harm to the water body.
The wastewater produced by pulping is most seriously polluted. The wastewater discharged during pulp washing is dark brown, which is called black liquor.
In the papermaking process, the wastewater discharged from the front end of the papermaking machine is called white water, which contains a large amount of fibers and fillers and sizing materials added in the production process, most of which are useful substances.
working principle:
The working principle of the paper mill wastewater treatment equipment is to make a suitable amount of air and part of the reflux water form a saturated dissolved air carrier in the dissolved air tank under a certain pressure (0.35~0.45Mpa), and then a large amount of fine air bubbles are obtained by sudden decompression through the releaser. It quickly adheres to the flowing particles in the water, emulsified oil, baths and flocs that have undergone coagulation reaction, resulting in a state where the specific gravity of the flocs is less than that of water, and is forced to float quickly on the water surface, thereby achieving solid-liquid separation.
1. In the process combination of complex and difficult wastewater treatment, the air flotation treatment is also accompanied by the phenomenon of attached aeration, which reduces the surface activity and organic concentration, greatly reduces the oxygen consumption, and promotes the further purification of the wastewater. Sub-treatment provides water quality that is conducive to compliance.
2. Dissolved air system For the air flotation equipment of industrial sewage treatment equipment, the dissolved air system is like the "heart" of the air flotation equipment, and it is also the main component of the air flotation equipment. At this stage, the air and water are at the inlet of the pump. Inhaled together, mixed into dissolved gas and water by shearing and pressure, the gas-liquid two phases are fully mixed and saturated, the maximum gas content of the entire dissolved gas system is 10%, and the gas solubility is 99.99%, so that the gas is dispersed slightly. The bubbles are evenly distributed, and the average bubble diameter is less than 30um.
3. Slag scraper The operation mode and speed of the slag scraper directly affect the water quality of the flotation water and the solid content of the sludge. Vortex concave air flotation machine The system adopts a rotary slag scraper, which can continuously and evenly remove the scum.
4. Control system The control system adopts advanced electrical components (Delixi or Chint) to ensure the long-term and effective operation of the equipment.
