Method for comprehensively using pulping waste water by sulfite method

Abstract

The invention discloses a method for comprehensively using pulping waste water by a sulfite method. The method comprises the steps of pretreatment, bag type filtration, continuous impurity removal of micro-filtration membranes, continuous separation of ultra-filtration membranes, ion exchange, continuous concentration of nano-filtration membranes, and treatment of nano-filtration concentration dialysis water by using reverse osmosis membranes. The method can effectively separate and recover valuable substances, such as lignosulfonate, oligosaccharide and the like in the pulping waste water so as to improve the comprehensive utilization rate of bamboo pulp resources, can strength the pretreatment of papermaking waste water before membrane entrance so as to avoid the dirt blockage problem of membrane holes due to effective removal of easy fouling substances which pollute the membranes and to largely prolong the service life of membrane modules, and can separate and extract the lignosulfonate and revertose by adopting the continuous dialysis membrane ultra-filtration separation and washing method to effectively solve the difficulties of membrane pollution and separation efficiency decrement and to be applied in the treatment of the papermaking waste water in large scale; and the membrane materials are preferentially hydrophilic materials, so that high water passing quantity and reduced membrane pollution are guaranteed.

Description

technical field [0001] The invention relates to a method for comprehensively utilizing pulping wastewater by a sulfite method. Background technique [0002] The paper industry is a traditional large water user and one of the important sources of water pollution. The sewage discharge of my country's pulp and paper industry is second only to metallurgy and petrochemical industry, ranking third. With the development of the economy, enterprises are increasingly facing the problems of water shortage and shortage of raw materials. On the other hand, water pollution is becoming more and more serious. At present, my country's paper industry wastewater discharge and COD discharge rank first among all types of industrial emissions in my country, and the paper industry has the most serious pollution to the water environment. The primary issue to be dealt with. Its comprehensive management has a long way to go, and the corresponding processing costs remain high. In 2008, 2009, and 201...

AI Technical Summary

Problems solved by technology

The use of primary sedimentation and secondary biochemical treatment methods is a relatively mature technology for the treatment of papermaking wastewater, but there are still deficiencies in the actual effect: the chroma of the discharged wastewater is high, and the COD value is also high, which requires papermaking enterprises to invest a lot of financial and material resources to ensure Wastewater discharge meets the discharge standard

The existing problems are: (1) The comprehensive utilization rate of bamboo and wood pulp resources is not high, and a large amount of carbohydrates in the wastewater have not been utilized; (2) The waste liquid is directly concentrated by multi-effect evaporation, which consumes a lot of steam and concentrates The cost is very high. Generally, the cost of multi-effect evaporation and concentration per ton of water is about 50-60 yuan

However, the membrane technology is rarely used in production practice. The fundamental reason is that the problems of membrane pollution and rapid decline in separation effect have not been solved, resulting in frequent cleaning and short service life of the membrane, which generally does not exceed one year; at the same time The existing membrane technology is applied to the treatment process of papermaking wastewater, and there is no optimized design for the membrane process of papermaking wastewater

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