WATER CONSUMPTION ANALYSIS OF SMALL ISLANDS SUPPLIED WITH DESALINATED WATER IN INDONESIA

Abstract

 Water supply systems on small islands are fragile and prone to water shortages. Although the Indonesian Government provided assistance to build sea water reverse-osmosis (SWRO) systems on small islands to alleviate water shortages, the inhabitants also have other water sources. Therefore, this study aimed to delineate the inhabitants’ preference and consumption of various water sources, including the SWRO systems, and to find factors affecting water consumption to propose the sustainable operation and management of the SWRO systems. The three islands, namely Belakang Padang Island (BPI), Tanakeke Island (TKI) and Nusa Lembongan Island (NLI), have almost the same SWRO systems with different capacities. In BPI, high pressure pumps (HPP) were broken occasionally, reducing the production capacity significantly. Meanwhile, in TKI and NLI, the SWROs were operated intermittently due to solar power failure and small SWRO water consumption in the rainy season (TKI), and distribution pipe breakage (NLI). The SWRO water consumption by the customers varied significantly: 12, 46, and 110 litters-percapita-per-day (LPCD) on TKI, BPI and NLI, respectively. SWRO water consumption in the dry season was much higher than that in the rainy season when the customers can use rain water. The water consumption of the SWRO systems was also influenced by the operational stability of the SWRO systems, household income levels, and the water tariff levels. About 67% of the surveyed households spent more than 4% of their income for getting water. Since the SWRO systems cannot produce sufficient amounts of water to meet the dry season demand, many customers buy water from other sources that are more expensive than the SWRO water. Therefore, reliable and stable operation of the SWRO systems would lessen the customers’ burden of expenditure for getting water.