Objective To understand the water quality and influencing factors of household activated carbon water filters by water quality index (WQI).
Methods A total of 248 households using activated carbon water filters were recruited for this study in Jul 2011. Inlet and outlet water of filters were sampled in the selected household. The water analysis consisted of iron, manganese, copper, zinc, lead, arsenic, chemical oxygen demand (COD), pH, color, turbidity, total bacterial count, and coliform. A WQI for activated carbon water filters was developed subsequently. χ2 test and binary logistic model were used to analyze the influencing factors of WQI.
Results The unqualified rates of the elimination rate of COD and total bacterial count were 37.5% and 16.1% respectively. The results of WQI calculation for 89 filters (35.9% of total) were above pollution level. Both univariate and multivariate analyses showed that the influencing factors of the WQI of treated water from household activated carbon water filters were ultraviolet unit installation, inlet water quality, and water treatment capacity of core cartridge (P<0.05).
Conclusion Hygienic issues are identified in the household activated carbon water filters investigated and are influenced by several factors. Besides, the study demonstrates the capability of WQI to reflect the comprehensive conditions of water quality and the potential to be applied to sanitary assessment of water filters.
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