Investigating iron bacteria in catalytic biofilm in underground waters at the Velizhany water treatment facilities of Tumen

Summary

Underground water used for drinking water supply of Tumen is characterized by high concentrations of iron and manganese that 1.3–10.59 times exceed the maximum permissible level. Iron and manganese can be efficiently removed from natural water with the help of microbiological oxidation and sorption processes. The studies aimed at analyzing the underground source for the presence of iron bacteria group and determining the rate of catalytical biofilm formation. Water analysis for the presence of iron bacteria was carried out in sand filters of the Velizhany water treatment facilities by microscopic method with the use of iron cytochrome coloring with potassium ferrocyanide on exposed specimen slides. The slides were placed on styrofoam floats installed in the filters of the water treatment facilities. The results of the studies showed that the water from the underground source contained iron bacteria – they were found in catalytic biofilm. It was stated that the rate of biofilm generation with the participation of iron bacteria in sand filters of the Velizhany water treatment facilities at the media level was in average twice as high compared to the level of surface of the water being treated. Mass growth of iron bacteria on sand media proceeded for 8–12 hours; in the water being treated – for 22–24 hours. It might be caused by biological oxidation of iron and manganese at the media level. The studies carried out confirm the possible use of iron bacteria of catalytic biofilm in biological removal of iron and manganese from underground water at the Velizhany water treatment facilities.

Key words

biological treatment , ground water , iron , manganese , water treatment facilities , iron bacteria , catalytic biofilm , sand filter

Special aspects of choosing the methods of single-stage deironing and demanganization of underground waters

Summary

Special aspects of choosing the methods of deironing and demanganization of underground water depending on the physical, chemical and microbiological properties in a single-stage water treatment process are described. The method of removing excessive concentrations of iron and manganese shall be chosen in the process of studies at the pre-project phase of front-end engineering and design. For underground water containing apart from manganese also iron mainly as oxides, the physical and chemical methods that combine pretreatment of raw water with a strong oxidant (sodium hypochlorite, ozone etc.) and subsequent filtration through chemically active material are most acceptable. Biological method of water deironing and demanganization is conditioned by the presence of microbiocenosis with the life cycle associated with the processes of iron and manganese oxidation in the ecosystem of the treatment facilities. The procedures of filter media inoculation with Crenothrix and Siderocapsa – Arthrobacter bacterial cultures are described. Based on the experience of operating «Vostochnyi-2» facilities for underground drainage water deironing and demanganization with a capacity of 25,000 m3/day in Krasnodar the use of the physical and chemical method of water treatment was justified. The results of operating a water treatment plant in «Yuzhnyi» settlement of Barnaul city show the efficiency of the biological method of underground water deironing and demanganization conditioned by the presence of microbiocenosis with the life cycle associated with the processes of iron and manganese oxidation in the ecosystem of the treatment facilities.

Key words

ground water , iron , manganese , iron bacteria , single-stage deironing and demanganation , catalytically active filtering material