On increasing the capacity of UV-units for liquid disinfection

Summary

The results of theoretical studies of the possible capacity improvement of units for disinfecting liquids including water by ultraviolet irradiation eliminating any increase in energy consumption are presented. Capacity improvement is possible at the fixed reactor geometry and source strength owing to the redistribution of liquid flows in the reactor. It is shown that the maximum possible efficient radiation dose is equal to the mean by reactor volume radiation intensity multiplied by the mean time of liquid residence in the reactor. The necessary and sufficient condition for obtaining this dose is the availability of liquid flow in every point of the reactor volume and equal radiation dose for every microvolume of liquid. By way of example the calculations of the maximum possible radiation dose for a spherical reactor with a point source of radiation and for a cylindrical reactor with a linear radiation source are presented. It is noted that widely manufactured at present UV water disinfection unit designs with a single source (a lamp) use only 30% of the source capacity. The design with a cylindrical reactor and spiral downward liquid flow distributed along the reactor length provides for the maximum possible radiation dose and/or capacity of the installation.

Key words

water disinfection , ultraviolet irradiation , irradiation dose , reactor , installation capacity

Pulsation mixing apparatus for preparation of chemicals

Summary

One of the methods of liquid media mixing and chemical dissolution is pulsation mixing of liquid. This method was used in nuclear industry when absolute safety was required, whereas the presence of a man was eliminated. Pulsation mixing apparatus do not have any moving parts in the reaction zone of the apparatus and can be made of materials resistant to the chemicals used, mechanically undurable. The emergence of a large variety of plastics provides for the significant simplification of manufacturing mixing apparatus. Though they are somewhat behind mechanical mixers in energy consumption nevertheless they provide for more uniform mixing and possible operation after the reactor has been charged with solid chemicals. The mixing intensity can be regulated within a wide range. On the basis of advanced technology manufacturing pulsation mixing apparatus for the preparation of chemicals for water treatment that provide for easy regulating the mixing intensity for fast preparation of different chemical solutions was restored.

Key words

reagent , reactor , pulsation mixing apparatus , jet mixing , pulsation chamber