Chongqing Water treatment Equipment Company discusses the wastewater treatment method in the process of papermaking
Water treatment is a very important project at present。We have to drink water every day, whether it is clean water quality and sewage after a series of treatment processes of water treatment equipment, it is also very good for our life。The water treatment equipment needed for water treatment is also diversified。
1. Grille and screen
Because papermaking wastewater often contains small suspended substances, such as bark, wood chips, plastics, pulp fiber chips, etc., for example, the wastewater discharged in the pulping process of wood-based pulping plants often contains bark, wood chips, etc。Paper making process will produce a lot of white water, white water contains a high fiber concentration。These substances can cause damage to the pump and affect the main treatment process, especially the water distribution system in biological treatment, such as UASB, hydrolytic acidification, etc。So before going into the pump and the main processing system, intercept it, set up a grid to intercept the big suspension, set up a screen to intercept the fine suspension。
Grilles are generally used to treat papermaking wastewater containing a lot of water。Due to the large amount of sewage and a wide variety of suspended solids, the grid can effectively trap large suspended solids, with large processing capacity and is not easy to block。According to the characteristics of papermaking wastewater, thick grilles are generally used in engineering practice。The gap between the coarse grille and the fine grille is usually 10-15mm and 1-5mm。
The grille machine mainly includes rotating mechanical grille machine, mesh chain grille machine, fixed grille machine, reverse cutting rotary grille machine。The main models used by our company are reverse cutting rotary fine grid machine and net。Chain grille, fixed grille etc
Screens are usually used in wastewater with relatively little water content and a large amount of suspended matter (such as pulp)。At the same time, it can remove large particles of floating matter。The removal rate of suspended matter and large particulate matter can reach more than 90%。Engineering practice shows that，The screen gap is generally 30-60 mesh，The installation mode is fixed installation，The installation Angle is 40-50 degrees，The installation Angle is not too large，Excessive water load will be reduced，Processing power is reduced，But it will also increase some investment，Too small will easily cause screen blockage，Increase the difficulty of slag removal，Affect the treatment effect。
2, fiber recovery system
Pulp wastewater contains a lot of pulp fibers。If the pulp fiber is not recycled, there will be a large number of pulp into the wastewater treatment system, seriously affecting the treatment effect of the wastewater treatment system, but also cause the waste of pulp。Our fiber recovery system is mainly used for fiber recovery of papermaking white water。On the one hand, the white water cycle is carried out to reduce the discharge of white water;On the other hand, the pulp fiber is recovered by sieve, multi-disk filtration, air flotation, precipitation and other methods。In the recovery of pulp fibers, the method of screening and filtration is often used。
The screening filter mainly includes gravity flow screen filter, general rotary filter, anti-tangential unidirectional flow rotary filter, bidirectional flow rotary filter, etc。
The gravity flow screen filter distributes the wastewater evenly to the screen through the overflow of the collecting tank。Due to gravity, the filtrate flows out of the gap of the screen, and the pulp fibers flow along the screen into the slag under the action of gravity and water。In the tank, the slurry is separated。
There is an Angle between the cartridge and the mounting place of the ordinary rotary filter。Waste water enters the drum from the top。The inner wall of the inlet filter is at a 90 degree Angle。During the rotation process, the filter bucket drains the filtrate from the filter gap, and the pulp is automatically discharged to the other end of the filter bucket。
The reverse tangential unidirectional flow rotary filter adopts horizontal drum structure。Transmission mode can be divided into chain type and gear type。The wastewater is evenly distributed in the inner wall of the filter screen along the reverse flow direction, and the flow of water and the filter screen forms tangential relative motion。The filtrate is discharged from the network port, the pulp fiber is cut off in the inner wall of the network, and is automatically discharged from the slag discharge end under the action of the guide plate。In order to achieve the separation of pulp and wastewater, the principle of the reverse tangential bidirectional flow filter is the same as that of the unidirectional flow。
3、调节
Due to the diversity of wastewater discharge in the paper industry, the quality and amount of wastewater change within a day, so it is necessary to adjust the wastewater, balance the water quality, and make it evenly enter the follow-up treatment unit。Improve treatment effect。Sewage treatment is mainly divided into: water quality control and water quality control。
Wastewater treatment equipment and structures are designed according to certain water volume standards and require a uniform inflow of water, especially for biological treatment systems。In order to ensure the normal operation of the subsequent treatment system, the amount of water is pre-regulated before the wastewater enters the treatment system。The processing system meets the design requirements。
According to the different process flow of the paper industry, the amount of wastewater and water quality are different, and the residence time of the regulation tank is also different。When the amount of water treated is relatively small, a larger residence time can be selected。When the amount of water treated is large, a smaller residence time can be selected according to the specific situation, generally 4-8 hours。
While most of the suspended solids are removed by grilles and fibre recovery measures before the effluent enters the Ordinance, some suspended solids, especially pulp, still flow into the conditioning tank to prevent precipitation and improve the uniformity of the wastewater。Adding aeration equipment in the regulating tank can effectively improve the characteristics of wastewater quality。
The above is all the content of the small edition of Chongqing water treatment equipment Haferong Company to share, I hope to help you。If you need to know more about Chongqing water treatment equipment, please pay attention to our official website of Chongqing Haferong Water treatment Equipment Co., Ltd. or call for consultation, we will be happy to serve you, thank you for your support!
