Microbiological safety of water systems
Biofilms, or so-called biological growths, are very common in water systems. These biological-chemical structures deposited on surfaces in contact with water pose a danger to many industries. They are a threat to both the end users of final products and the manufacturers. The formation of biofilms is a fairly common phenomenon, but the main reason why many companies pay attention to the effects of their occurrence is the emerging increase in the number of coliforms measured in water. These indicators of water sanitation often accompany other heterotrophic bacteria that form biofilms.
The occurrence of biofilms may be related to a number of physicochemical factors, the most important of which are the water treatment method, the type of disinfectant, the level of assimilable organic carbon and the type of material. Water containing high levels of assimilable organic carbon (AOC) is more difficult to disinfect. For example, chlorinated water with AOC levels higher than 100 μg/L has significantly more samples showing coliforms. The type of installation material as well as the accumulation of corrosion products can drastically affect the formation of biofilms in drinking water systems. It is worth noting that localised defects in the installation material can provide specific habitats - protective niches for bacteria growth. The formation of pits in metal pipes, for example, can be accelerated by high chloride and sulphate levels. The ratio of chlorides and sulphates to bicarbonates, known as the so-called Larson index, can indicate the tendency of a system to pitting corrosion. The value of this Larson index can vary seasonally, peaking in the summer months when water temperatures in water systems tend to be higher.
The result of research conducted in cooperation with industry and Polish Academy of Sciences units was a thorough understanding of the problems associated with the functioning of water distribution systems. Effective antibiofilm strategies have been developed, based on surface modification with active organosilane silicon polymers, whose chains are attached at one end to the surface of the material to be modified. The nature of the chains can be altered accordingly, thereby improving the surface characteristics of the installation material.
Completed projects:
1. KBN N205 129935 "Surface modification of inorganic materials to give them adhesive or antiadhesive properties for microorganisms"
2. Research work I31/323/B " Microbiological studies on purified water
3. Research work I31/326/B " Microbiological studies of water from deep water intakes".
Social and economic benefits from the implementation of project results:
Thanks to the interdisciplinary research, the cooperation of scientific and research institutions in the area of surface modification has been significantly strengthened. Extensive cooperation with leading scientific units of the Polish Academy of Sciences has allowed to develop comprehensive solutions to remove already formed biofilms and to prevent their formation. The research has a significant economic and social importance, both domestically and internationally, because the losses resulting from biofilm formation (product contamination, flow disturbances, biodeterioration) are enormous and difficult to estimate.