Abstrakt

Gdańsk region is situated in the area with good hydrogeological conditions. The ground-water designed for drinking purposes is taken mainly from the Quaternary and addition-ally from Cretaceous aquifers. The urban development and intensive take off have caused the increase of water exploitation and as a consequence of the changes of hydrogeological conditions the deterioration of chemical and bacteriological quality of water has been observed. Routine bacteriological quality control doesn't include some specific bacteria which are characteristic for groundwater environment and can have negative influence on the physical and chemical properties of water. Among such bacte-ria there are manganese-oxidizing bacteria, iron-binding bacteria and sulphate reducing bacteria (SRB). In the paper frequency of SRB occurrence in raw water from Cretaceous and Quaternary formations and in treated water has been described. It has been proved that isolated consortiums of bacteria show preference to sodium lactate, as a main source of carbon and energy. In the metabolic processes SRB partly oxidise lactate and accu-mulate acetate. The presence of SRB in treated water and its negative influence on the quality of water in distribution network, makes it necessary to disinfect treated water periodically or permanently. It has been proved that UV radiation and microfiltration are the effective methods of SRB elimination from the groundwater.

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