EFFICIENCY OF FLOCULUVES TO REMOVE COWLINES FROM WATER

Abstract

The paper presents the results of studies of the effectiveness of different types of flocculants in the processes of illumination of kaolin suspensions. It is established that the suspension of kaolin particles is characterized by high dispersion and is difficult to be exposed to light. At initial turbidity of a suspension of 225 mg/dm3, the residual solids content in water after settling for 2 hours is 75 mg/dm3. The influence of different types of flocculants on the intensification of the processes of protection is studied. Fluorescents Magnafloc-156 with anionic charge and molecular weight up to 20 million c. u. in flocculants were used as reagents and Zetag-7692 with cation charge and molecular weight up to 20 million c. u. as well as solutions of polyacrylamide (PAA) as a nonionic flocculant. The effectiveness of Magnafloc-156 flocculant was rather low and, in general, the addition of this reagent only inhibits the process of lighting. If at concentration of flocculant 1 mg/dm3 the intensity of protection is comparable to the intensity of resistance without treatment with reagents, further increase of concentration only worsens the situation. At the same time, the minimum residual concentration of solid phase in treated water at a content of flocculant 10 mg/dm3 was only 10.3 mg/dm3, but the minimum apparent volume of sediment thus – 94 % of the initial volume of the suspension, which does not allow the reagent to be considered suitable for practical use. The effectiveness of the Zetag-7692 flocculant proved to be much better, even though its properties significantly differ from the similar properties of the previous flocculant. Although the minimum apparent volume of the solid phase after 2 hours of defrosting was 79 % of the initial volume of suspension at a residual solid phase concentration of 29 mg/dm3, such indicators do not allow to recommend this reagent for use in the treatment of water containing a significant amount of particles kaolin The use of PAA allowed to get the best result in the scope of this work. At pH 4 there is a decrease in the imaginary volume of solid phase to 60 % of the initial volume of suspension. This value could not be recorded for other conditions under the conditions studied for other flocculants. At other values of pH this increase is not observed. The use of PAA also provides the lowest residual solids concentration in the solvent for 2 hours of suspension. Moreover, with an increase in pH to 11, they grow more than 2 times. However, even with such results, PAA can not be considered as sufficient reagent to remove kaolin particles from the aqueous medium. Thus, none of the three types of investigated flocculants does not provide regulatory requirements for the solid phase content in drinking water treated with settling.Key words: kaolin, flocculant, settling, lighting, water treatment, reduction of turbidity of water.