Impact of intermittent water supply on water quality in Lebanon

Abstract
Lebanon in general and its capital, Beirut, suffer from water shortage due to the increasing water demand and the lack of proper management despite its abundant water resources. An intermittent water supply strategy was implemented in order to minimise deficiency problems. This, however, can seriously affect water quality due to the potential suction of non-potable water by negative pressures, biofilm detachment, and microbial re-growth especially when static conditions occur. Intermittent supplies also entail storing water in household tanks to satisfy demand during no-flow periods, and these tanks often encourage bacterial re-growth. Dumping of disinfectants in order to circumvent bacterial presence and the subsequent formation of undesirable byproducts is another concern. A study was conducted in Beirut over an eight-month period, during which samples were collected from household tanks and drinking water taps of Beirut's network. This paper presents the findings of the study and highlights key aspects in intermittent water supply systems.