Selection Of Polyacrylamide In Industrial Wastewater Treatment
【classification of industrial waste water】
The chemical properties of major pollutants in industrial waste water can be divided into: organic waste water mainly containing organic pollutants, inorganic waste water mainly containing inorganic pollutants, and mixed waste water containing organic matter and inorganic matter.
According to the object of industrial processing, industrial waste water can be divided into: metallurgical waste water, textile waste water, paper waste water, leather waste water, pharmaceutical waste water, oil refining waste water, mineral processing industry, dyeing industry and sugar industry.
Activated sludge treatment is commonly used in urban sewage and industrial sewage. Biochemical sludge is often a highly hydrophilic colloid with high organic content and extremely difficult to be dehydrated.Treatment with cationic polyacrylamide, low dosage, high dehydration efficiency, easy to separate.
Cationic polyacrylamide is several times more effective or dozens of times more effective than anionic polyacrylamide, non-ionic polyacrylamide or inorganic salt.Because such wastewater is generally negatively charged.
According to the industrial wastewater treatment industry, the corresponding ionic models are different.Firstly, the model of polyacrylamide is selected and the wastewater quality of a certain industry is tested to determine the type suitable for the water quality: cationic, anionic, non-ionic and amphiprotic, and then the product molecular weight is selected according to the selected type, eg. the product with high solid content of wastewater is selected with low molecular weight. Finally, according to the amount of sewage to determine the amount of use.
For example, industrial papermaking wastewater treatment, because the amount of wastewater generated from papermaking is relatively large, with a large amount of suspended substances and higher organic concentration, the main purpose of the pollutant and treatment in the waste water of the paper mill is to remove chroma and COD.Through water sample test, flocculation precipitation process was adopted, and 15 million molecular weight anionic polyacrylamide and polymeric aluminum chloride coagulant were selected for use, which can effectively remove the chroma of papermaking wastewater, and remove most of the insoluble COD and partially dissolved COD and BOD, achieving ideal treatment effect.
Polyacrylamide products are mainly used as coagulant or flocculant in industrial waste water treatment. As the molecular chain contains a certain amount of polar genes which can adsorb the suspended solid particles in water, the particle bridge forms large flocculation.It can accelerate the sedimentation of particles in the suspension, accelerate the clarification of the solution, and promote the effect of filtration.Generally in sewage treatment (floating or precipitation) with organic polymer (PAC) and inorganic polymer flocculant (PAM), and in the period of treatment is sludge dewatering, most of the organic polymer flocculant (cationic polyacrylamide) sludge dehydration to make use of, individual sewage sludge dewatering of anionic polyacrylamide choice, this should be according to the actual circumstance of field to further determined.