Views: 2 Author: Site Editor Publish Time: 2021-06-26 Origin: Site
With the improvement of the degree of sealing of paper machine white water, dissolved substances and colloids (DCS) in the white water also accumulate, which will not only lead to the increase of anionic interference substances, but also cause a large number of bacteria to multiply, which seriously affects the chemical production of pulp bleaching. Use efficiency. In actual production, to reduce the PCD value in white water, the following methods can be used:
(1) Appropriate degree of closed circulation of white water. Reduce the pollution load of wastewater, add fungicides to limit the number of bacteria, and reduce anionic waste.
(2) Clean the entire system regularly. It can remove stubborn deposits, while appropriately increasing the temperature of the cleaning solution can speed up the reaction speed of the cleaning solution and improve the cleaning effect.
(3) Use squeezed filtrate membrane to treat filtrate wastewater. It can remove the suspended solids and anionic garbage in the wastewater, and reduce the COD in the wastewater, and the treated filtrate can be directly reused in the production line to replace the application of tap water.
(4) Use super-efficiency shallow air flotation technology to treat white water. The removal rate of suspended solids is high, which can effectively reduce the content of anionic interference substances in the white water, and can also remove some soluble COD and BOD.
(5) Strengthen the selection and optimization of paper machine wet end chemical additives. Ensuring the addition point and order of chemicals will help promote adsorption on the surface of fibers and fillers and good particle effects. It can increase the retention rate of fine fibers and fillers in a single pass, reduce the concentration of thick white water under the wire, and improve the papermaking system. The degree of white water closed circulation.
(6) Add chemicals such as anion collectors and flocculants to the wet part of the paper machine. The treatment effect of adding PAC and PAM or bentonite and PAM has great room for improvement. The PCD is greatly reduced, the turbidity of the effluent is greatly reduced, and the pH value is reduced.