Clarification of turbid water with the use of Praestol 650 flocculant

Summary

The efficiency of the individual use of the cationic flocculant Praestol 650 for the purification of turbid water is considered, depending on the turbidity of the source water and the conditions of flocculation. It is shown that the priority parameters that determine the effectiveness of the individual use of the cationic flocculant Praestol 650 for the purification of turbid natural water are the intensity and duration of mixing in the flocculation chamber. With a duration of at least 20 min and an average gradient of mixing rate G = 340 s-1, the efficiency of turbidity reduction is 96% (final turbidity being 7 mg/l). A 96% efficiency of the non-ionic flocculant with a molecular weight of 5–7 million was determined in a suboptimal flocculation mode with a mixing period of 5 min and G = 65 s-1.

Key words

settling , turbidity , flocculation , cationic flocculant , water clarification , mixing rate gradient

The use of organic coagulants for turbid water clarification

Summary

The results of studies of the coagulating ability of domestic organic coagulants of well-known brands for the treatment of turbid waters with color not exceeding the water quality target, depending on the characteristics of the coagulants, water turbidity and process parameters of coagulation and sedimentation are presented. The efficiency of using organic coagulants VPK-402, Kaustamin-15 and Biopag to reduce the turbidity of water caused by fine-grained clay particles with a hydraulic size of less than 0.01 mm/s is considered. It was found that VPK-402 coagulant characterized by the highest molecular weight, possessed the greatest coagulating ability. It was shown that the dose of the coagulant did not exceed 0.4 mg/l with an increase in the turbidity of the source water to 750 mg/l. The maximum reduction in water turbidity by sedimentation with the use of organic coagulants is observed with a flocculation time of 20 minutes, where 83–84% of the resulting flocs have a hydraulic size of more than 0.8 mm/s.

Key words

settling , turbidity , flocculation , hydraulic size , organic coagulants , water clarification