Water quality study on the hot and cold water supply systems at vietnamese hotels

Abstract

This study was conducted as part of the Joint Crediting Mechanism (JCM) of the Japanese Ministry of Economy, Trade and Industry, and the Ministry of the Environment project's preparation in Vietnam. Samples were taken from hot and cold water supplies from guest rooms' faucets in 12 hotels in Hanoi city, Vietnam, and 13 hotels in Japan for comparison. A simple water quality measurement and determination of Legionella was carried out. The results showed that residual effective chlorine-which guarantees bactericidal properties-was not detected in tap water supplied in hotel rooms in Vietnam, and nitrite (an indicator of water pollution) was detected in 40% of buildings. In the hotels in Japan, the prescribed residual chlorine concentration met the prescribed levels, and nitrite was not detected. Additionally, while there was no Legionella detected in the Japanese cases, it was detected in most of the Vietnamese hotels, which were found to manage the hot water storage tank at low temperatures of 40-50 °C. It was found that there were deficiencies in cold and hot water supply quality, and that there was no effective system in place for building operation maintenance and management.