Investigation and monitoring of microbial pollution (bacteriaand Giardia protozoan) in urban water and production water ofhousehold water treatment plant in Ardabil, Iran

Background and Aim : Household water purifiers are widely used in recent years to improve thequality of drinking water by removing odor, taste, turbidity, color, pathogenic organisms, toxicchemicals, organic matter, and carcinogens. The indexes of heterotrophic bacteria, Total Coliform,Thermotolerant Coliform, E.coli, and Giardia lamblia protozoan were investigated in this studyfrom March ۲۰۲۱ to February ۲۰۲۲ in untreated water, municipal water, and water produced by ahousehold water purifier in Ardabil, Iran.Methods : In this descriptive-analytical study, water samples from Yamchi dam (Ardabil) and ۵۰samples from water distribution network and inlet and outlet of domestic water purifiers werecollected. Coliforms and HPC were tested by the standard methods using MPN method, SpreadPlate, IMVIC and TSI diagnostic tests, as well as Giardia lamblia by the membrane filtrationmethod.Results : The findings of this study revealed that there is a significant difference in the number ofcolonies in the Total Coliform, Total Coliform, Thermotolerant Coliform (p <۰.۰۰۱) and E.coli (p<۰.۰۵) bacterial colonies in water samples collected behind the dam, municipal water distributionnetwork and treatment plant outlets household water (winter season) in different seasons of theyear. The bacteria colonies were high in water samples collected behind the dam. There were noreports of Giardia lamblia. There is no significant relationship between temperature (p = ۰.۱) andchlorine (p = ۰.۸) and heterotrophic bacteria in the water produced by household water purifiers.In the purifier, however, there is a significant relationship between water pH and HPC (p = ۰.۰۱).Conclusion : The presence of Total Coliform, Thermotolerant Coliform, and E.coli bacteria in theuntreated water behind the dam differs significantly from municipal water and the output ofhousehold water purifiers. It also slightly increases the growth of Heterotrophic bacteria in homewater treatment systems due to pH changes.

کلیدواژه ها:

Coliforms ، Municipal Water ، Household Water Purifier ، Giardia Lamblia ، HPC ، MPN