New process flow scheme for wastewater treatment by pressure flotation

Summary

The results of calculating a circulation unit for converting the Q–H-characteristics of an impeller pump with the withdrawal of the useful fluid flow upstream the waterjet pump are presented. Mathematical dependencies are obtained that adequately describe the process of the operation of the circulation unit for the conversion of the Q–H-characteristics of an impeller pump. It has been theoretically substantiated and experimentally proved that replacing a high-pressure waterjet pump in the circulation unit with two sequentially operating medium-pressure waterjet pumps ensures the sustainable atmosphere air ejection and reliable operation of the pressure flotation unit, provided the hydraulic efficiency of the circulating unit is reduced from 42 to 33% and the useful flow rate Qн decreases slightly. The proposed process flow scheme of pressure flotation that involves the use of a circulation unit to convert the Q–H-characteristics of an impeller pump with two medium-pressure waterjet pumps operating in series, provides for abandoning the use of an expensive compressor and replacing a high-pressure impeller pump with a cheaper pump with lower operating pressure.

Key words

wastewater treatment , pressure flotation , impeller pump , waterjet pump , circulation unit , coefficient of ejection , relative pressure drop