In the advanced treatment of papermaking wastewater, physical and chemical methods have the advantages of fast treatment and good treatment effects. The commonly used methods include advanced oxidation, flocculation and precipitation, and membrane separation adsorption.
Advanced Oxidation Processes (AOPs), also known as deep oxidation technology, is a new technology developed in the 1980s for the treatment of refractory organic pollutants. Under the action of oxidant, electricity, sound, light irradiation, catalyst, etc., it produces OH with extremely strong oxidation ability (its potential is 2.80 V, second only to 2.87 V of fluorine), and then through the addition of OH and organic compounds, Substitution, electron transfer, bond breaking, ring opening, etc., oxidatively degrade the difficult-to-degrade macromolecular organic matter in the wastewater into low-toxic or non-toxic small molecular substances, and even directly decompose into CO: and H: O, achieving harmlessness the goal of. The technology has the advantages of fast reaction speed, high treatment efficiency, thorough destruction of toxic pollutants, no secondary pollution, wide application range, easy operation, etc., and is widely used in toxic and refractory industrial wastewater such as pharmaceuticals, fine chemicals, printing and dyeing, etc. In the treatment of organic wastewater, it has gradually become a hot spot in the treatment of refractory wastewater. According to the way of generating free radicals and the different reaction conditions, they can be divided into Fenton type oxidation method, supercritical water oxidation method, photocatalytic oxidation method, ultrasonic oxidation method, electrocatalytic oxidation method, ozone oxidation method and wet oxidation method, etc.
Flocculation sedimentation method
Flocculation sedimentation method is a method often used by the technical department of Boyuan Water Purification Materials Company. A method of removing the polymerized product formed by the flocculant (polyacrylamide) through a series of effects on the suspended and colloidal macromolecular mass pollutants in the water. For the tertiary treatment of pulping and papermaking wastewater, this method has been widely used. Under the best operating conditions, using flocculation-electric flotation to continuously treat papermaking wastewater, the COD cr of the wastewater can be reduced from 1416mg/L to 48.9 mg/L.
The membrane separation method uses a special semi-permeable membrane to separate the solute and the solvent, so that a certain solute in the solution on one side can penetrate through the membrane or the solvent, so as to achieve the purpose of separating the solvent. Guan Yuntao and others used a traditional two-phase anaerobic process (BS) combined with membrane separation technology (MBS) to treat papermaking black liquor configuration wastewater. The results showed that the COD removal rate of the system can reach 73.1, which is higher than that of the BS system ( 48.6%), and is superior to the BS system in terms of anaerobic sludge activity and operational stability; when the COD load is 6kg•(m3•d)-1, the MBS acidification rate is 20.1%, and the acidification level is 7.5%, slightly better In the BS system (7.0% and 5.0% respectively).
