Purification of underground water containing high concentrations of silicon, iron and manganese

Summary

The aspects of purification of underground water containing high concentrations of silicon, iron and manganese are considered. Different forms of silicon present in water are analyzed and the basic physics and chemistry of desilication are presented. The implementation of the technology of comprehensive purification of water containing high concentrations of silicon, iron and manganese is described. Through the example of three operating water treatment plants the negative effect of silicon on de-ironing and demanganation processes is shown. Two factors are accentuated that enhance the negative effect: the presence of organic admixtures in raw water and, possibly, higher degree of polymerization. Taking into account the application character of studies this presumption demands further study. The developed technology provides for water purification to drinking standard by every parameter. For the implementation of the technology dosing a great many of five types of chemicals (NaOH, Mg salts, NaClO, coagulant, flocculant) is required as well as large volume of sludge is subject to utilization. For this reason this technology is recommended for use only when an alternative water source is unavailable.

Key words

ground water , coagulation , iron , manganese , silicon , colloids , chemical precipitation , magnesium silicate