Factors affecting of drinking water quality of vending machine

Abstract

Drinking water from vending machines is treated with reverse osmosis and ultraviolet light to improve
the water quality of input and output water of the vending machine were analyzed as well as the overall hygienic
condition, the surrounding and the maintenance status. Sampling of 152 automatic water vending machines within
a radius of 500 meters from the Khon Kaen University were collected. The results indicated that most the raw
water derived from the city tap water (95.40%) met the drinking water quality standard, while a few machines
(4.60%) use underground water, 28.60 % of samples did not meet the standard of hardness content of ground
water for drinking. Output water from the vending machine met the quality standards (82.58%). Water quality
parameters did not meet standard were pH (5.58%), total bacteria (13.18%) and coliform bacteria (2.63%). All
owners of the investigated vending machines had neither been informed nor trained about drinking water quality
nor analysis of water from all the machines. However the hygienic environmental conditions of the location around
machines was likely god (76.97%) and the vending compartments was also at good level (87.50%). The quality
of drinking water was signifi cantly associated with vending machines without shutter or with a broken (P-value
=0.03, OR=2.91,95% CI= 0.93 to 8.46), and also affected by not maintenace the proper schedules for changing
the fi lters within the vending machines (P-value=0.03, OR=9.46, 95% CI : 0.47 to 562.5). It was concluded that
it was of importance to maintain a standard water quality delivered by automatic vending machines by changing
fi lters as suggested, keeping the water storage tanks clean and maintain the machines properly.