Method for treating middle section water of alkaline straw pulp

Abstract

The invention provides a treatment method for midcourse sewage in basic straw pulp. Wherein, pretreating the sewage in radial-flow deposition pond to remove leak fiber and mud; sending the supernatant into the hydrolysis acidification system; with the action of anaerobe, sending to physical-chemical treatment system when reducing pH value from 8.5-9.5 to 6.5-7.5; removing most hard biodegraded organic with high-efficiency water purification agent of composite polymerized iron aluminum chloride and polyacrylamide; sending the supernatant into the aeration biochemical treatment system, degrading most organic with aerobic bacteria; sending the supernatant into the first-stage stable pond to deposit the organic further, adding hypochlorite, chlorine dioxide and ozone for advanced treatment, and sending to the second stable pond for further deposition; sending the midcourse water to the main drain. The treated water has COD, BOD and SS less than 100mg / L, 10mg / L and 10mg / L respectively, and pH value within 6.5-7, is colorless and ordorless, and fits to irrigation and production.

Description

1. Technical field [0001] The invention relates to a papermaking mid-stage water treatment technology, in particular to a process for treating mid-stage water of alkaline straw pulp by adopting modern biological technology (anaerobic biochemistry, aerobic biochemistry), high-efficiency physicochemical flocculation technology and advanced treatment technology. [0002] The invention discloses a method for treating middle stage water of soda straw pulp. 2. Background technology [0003] At present, domestic and foreign chemical pulping is mainly based on wood pulping. This pulping process has the advantages of high black liquor extraction rate, high black liquor calorific value, and less black liquor. The black liquor treatment is recovered by alkali recovery technology. After alkali, heat and lime, due to the characteristics of low load and small water volume, the middle stage water can meet the requirements of complete reuse by using aerobic aerobic biochemical treatment tec...

AI Technical Summary

Problems solved by technology

Compared with the physical and chemical flocculation treatment technology, although the COD removal rate is higher, it can be close to or meet the current national standards (COD is less than 450mg / L), and the amount of sludge produced is less, but it is far from the target of these enterprises. The ideal requirement to be achieved is that the effluent of this process is not only high in COD, but the more troublesome is that its color is quite dark, and the more normal the system is running, the darker the color of the effluent. In most cases, the color of the effluent is heavier than that of the influent. The color of the water seems to have not been treated at all. The first impression is that all the pollutants are still in the water and have not been resolved.