Design Considerations For A Solar-Powered Desalinaton System For Remote Communities In Australia

DESALINATION
EI.SEVIER
Desalination 144 (2002) 193-199
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Design considerations for a solar-powered desalination system for remote communities in Australia
Bryce S. Richards”, Andrea I. Sch&ferb*
“Centre for Photovoltaic Engineering, The University of New South Wales, Sydney, NSW 2052, Australia Tel. +61 (2) 93854381; Fax +61 (2) 96624240; email:b.richards@unsw.edu.au “Centre for Water and Waste Technology, Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW 2052, Australia Tel. +61 (2) 93854470; Fax +61 (2) 93856139; email: a.schaefer@unsw.edu.au Received 13 February 2002; accepted 28 March 2002

Abstract

Water in many areas of Australia is scarce and of poor quality. In some areas high levels of treatment arerequired either due to contamination of waters or due to high salinity. Nanofiltration (NF) and low-pressure reverse osmosis membranes are well-recognized technologies to treat waters of qualities ranging from low salinity surface water to high salinity seawater. In remote communities the operation of such facilities may be limited by the availability of electricity. Solar, or photovoltaic, energy isthe ideal source of renewable energy in Australia to overcome this problem. This paper considers the various options for a small system, designed to deliver a permeate flow of 4001000 l/d from brackish wells. The most suitable membrane for salt retention and very high organics retention was selected and the pump energy requirements calculated. A submerged ultrafiltration (UF) membrane is used as analternative to the traditional sand and/or prefilter cartridges. The removal of natural organics is important where disinfection of the water is required, as chlorination of waters containing natural organics may produce potentially carcinogenic by-products. Keywords: Ultrafiltration; Nanofiltration; Photovoltaic; Submerged membrane; Remote community, Australia

1. Introduction
Good qualitydrinking water is often a scarce resource in many remote communities around the *Corresponding author. Congress on Membranes

world. Additionally, it is not always practical or possible for national electricity grids to provide power to these remote areas. Therefore, these communities are often chinking water of substandard quality, as they do not possess the electrical power and MembraneProcesses (ICOM), Toulouse, France,

Presented at the International July 7-12, 2002.

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or appropriate technology to purify the water. In Australia, nearly 800 remote indigenous communities rely ongroundwater as their main water source. In 1998 alone, about 350 of these communities experienced water restrictions, of which half were attributed to mechanical breakdown, effecting nearly 18000 people [ 11. The supply of fresh surface- and groundwater in Australia is limited to the northern and eastern coastal regions, while the western, central and southern regions are arid. However, there are majorbrackish groundwater reserves in most remote regions of the country [2], which typically exhibit high levels (3000-6000 mg/L) of salinity [3]. The Australian drinking water guidelines [4] recommend that good drinking water should contain not more than 250 mg/L of chloride, a hardness of 60-200 mg/L, and have less than 500 mg/L total dissolved solids (mainly inorganic salts). The adverse healtheffects of drinking highly mineralized water include: l kidney and gastric disorders [5]; l reduced consumption due to poor taste [3]; and l an increased sugar intake due to people adding cordial to the poor tasting water [6]. Additionally, there may be a possible link between the increased sugar levels and diabetes, which affects up to 30% of the people in some indigenous communities and can lead...