On the criteria of choosing the best available water treatment technology as applied to the Amur water intake (Komsomolsk-on-Amur city)

Summary

While choosing the technology of underground water conditioning it is advisable to be geared to the recommendations in SP 31.13330.2012 «Water supply. Public utilities», «Classifier of natural water treatment technologies» (NII VODGEO, 2000) as well as to minimizing the environmental impact. It is shown that intraformational treatment of underground waters meets to the maximal extent the requirements to the best available technologies and domestic standards developed on the basis of ISO 14000 International Standard. By the example of the Amur water intake of Komsomolsk-on-Amur city the complete conformity of the designed technology of intraformational iron and manganese compounds removal to the above-mentioned criteria with account of the specific water composition is noted. In discussing the specific features of underground water chemical treatment the attention is drawn to the inadmissibility of large-scale use of precursor – potassium permanganate for water conditioning. It is suggested to evaluate additionally the water treatment technology with account of the economical efficiency.

Key words

reagent treatment , ground water , water treatment , demanganization , intraformational treatment , deferrization

Removal of iron and manganese from natural water

Summary

The task of the study was investigating the impact of cavitation originating in low pressure devices of jet type on the kinetics of Fe²⁺ and Mn²⁺ ions oxidation as well as developing the method of chemical free removal of manganese and iron from natural water. The results of studies and the mechanisms of iron Fe²⁺ and manganese Mn²⁺ catalytic oxidation in water induced by cavitation are presented. The jet type device is equipped with a cartridge made in the form of a cone charged with crushed natural manganese mineral psilomelane or small steel chips. The particles of MnO₂ and (or) FeOOH catalyst getting into water as a result of corrosion of the charge under the impact of cavitation become centers on which a Fe²⁺ and Mn²⁺ ions adsorption and oxidation take place. It was stated that under these conditions Fe²⁺ oxidation was not a limiting stage whereas complete oxidation of Mn²⁺ ions with the initial concentration of 2 mg/l occurs within 5 minutes. The fast manganese oxidation in the reactor charged with steel chips is caused by high Fe⁰ corrosion rate induced by cavitation and catalytic effect of structureless iron hydroxides that are formed during the charge corrosion. The obtained experimental data allowed designing a process flow scheme of manganese and iron removal from water that included a cavitation module and ceramic membrane filters operating in cross-filtration mode. The dimensions and size of a water treatment unit with a capacity of 60 m³/day have been calculated.