The use of VPK-402 coagulant for the removal of suspended solids of different origin and dispersiveness from water

Summary

The coagulation ability of VPK-402 organic coagulant in reducing water turbidity determined by fine mineral particles of different origin and dispersiveness is considered. Water coagulation was carried out under laboratory conditions following the pattern: mixing-flocculation-sedimentation. The concentration of suspended solids in water was determined from turbidity; dispersivenes – from particle hydraulic size U0. The studies were carried out with modeling water with turbidity less than 115 mg/l containing mainly fine-dispersed suspension of bentonite clays, kaolin, quartz, calcium carbonate and titanium dioxide with less than 0.2 mm/s hydraulic size. It was found that the hydraulic size of clay suspensions was determined by their swelling capacity in water; whereas for quartz, calcium carbonate and titanium dioxide suspension – by the particle size distribution of the original minerals. The optimal dosage of VPK-402 for clay mineral coagulation does not depend on their dispersive characteristics and equals to 0.5 mg/l, i. e. 5–10 times higher than the coagulant dosages for modeling waters with finely dispersed particles of quartz, titanium dioxide or calcium carbonate. The efficiency of water clarification lowers with the increase of the percentage of particles with less than 0.05 mm/s hydraulic size irrespective of their origin. The results of the Kuban River water purification validated the obtained regularities. The efficiency of using VPK-402 organic coagulant for reducing water turbidity depending on the origin and dispersiveness (hydraulic size) of suspended solids represented by bentonite clay, kaolin, quartz, calcium carbonate and titanium dioxide particles is considered. The obtained results can be used in practice for optimization of water coagulation to remove suspended solids.

Key words

turbidity , suspended substances , chromaticity , coagulation , hydraulic size , natural water , organic coagulant , polyelectrolyte