Barbara Tchórzewska-Cieślak

Control of water quality changes in the distribution system is an important issue, due to consumer health, and a threat to technical infrastructure. Annual monitoring of water quality allowed us to analyze the physical, chemical, and biological stability of water produced in two different technological systems. The article examines the extent to which water purification technology affects the possibility of uncontrolled changes in water quality during its transport to the consumer (the risk of secondary water pollution has been estimated). Based on the obtained results, it was found that the groundwater treatment system based on the following processes—aeration, coagulation, sedimentation, filtration, and disinfection—does not ensure the effective elimination of biogenic substances that determine sanitary safety. The treatment technology extended by an additional biofiltration process on granulated activated carbons (GAC) contributed to the improvement of the quality of the treated water (lowering the content of nutrients) and reduced the risk of losing the biological stability of the water in the distribution system. The biofiltration process did not change the physical and chemical stability of the water; the calculated corrosiveness indicators showed that the waters are devoid of aggressive properties, with a tendency to precipitate CaCO3. The production of stable water is a step forward in controlling water quality from source to tap.