Microbial heterotrophic analysis of water network in Arak city and its correlation with MPN, water physicochemical parameters and pipe material

Providing safe and hygienic drinking water has an important effect on the health and well-being of society. This study aims to analyze microbial heterotrophy in the water network in Arak city and its correlation with physicochemical parameters and the material of water pipe network. In this cross-sectional study, 500 sampls have been randomly prepared from the drinking water network in Arak city in a standard condition, and some variables as HPC, MPN, free residual chlorine, turbidity, PH and temperature have been measured. Evaluation of the results obtained through regression analysis has been performed. Based on the statistical analysis, HPC variables, MPN, PH and turbidity have a significant relationship with the place (P-Value <0.01). There is a direct, but not significant, relationship between HPC and temperature (P-Value <0.05), while free residual chlorine values reversely ​​associate with HPC (P-Value <0.01). Application of Pour Plate and Spread Plate Method for determining the number of HPC bacteria showed that in most cases the Pour Plate Method super performs the Spread Plate Method. Identification of the bacteria isolated from positive HPC revealed that bacillus and Micrococcaceae family have the ability to be active in high chlorine condition. Monitoring of HPC is necessary as an important variable and effective in the control of drinking water bacteriological quality.