Necessity for replacing the filter media in the water treatment plant based on effective size and uniformity coefficient

 This study aims to compare the parameters in filtration unit of the plant with international guidelines. The results of this study would determine the necessity for replacing or renewing the anthracite and sand filter beds in phase I of IWTP. 

 In this field study, a total of 11 samples with a mass of 5 kg sand and anthracite media were analyzed. The media samples were evaluated in view of uniformity coefficient and effective size according to international soil classification. Data obtained were statistically analyzed using t-test at significance level (P < 0.05). 

 Results of this study showed that the uniformity coefficients of anthracite and sand media were 3.6 ± 0.4 and 1.93 ± 0.11 mm, respectively. Also, the effective sizes of anthracite and sand media were 0.68 ± 0.08 and 0.63 ± 0.05 mm, respectively. These values exceeded the international guidelines and had a significance difference with them (P-value < 0.05). 

 The results were shown that the uniformity coefficient and effective size of sand and anthracite media in the filters used in phase I of IWTP exceeded the guidelines and they need to be replaced with new media. Finally, based on the current study, filter beds were renewed.