Seite - 76 - in Clean Water Using Solar and Wind - Outside the Power Grid

76 Clean Water Using Solar and Wind: Outside the Power Grid consequences both for the design of the renewable energy source and for the operational life of the membranes (see also Chapter 10). The main maintenance issues are the cleaning of the solar panels and the difficulty of replacing RO pumps and modules. The most essential operational problems reported are: • Fouling in membrane modules that requires cleaning or replacement; • The booster pumps in the RO system (producing the high pressure). The most common failures reported are electronic device breakdowns and sensor failures. 5.4 DISINFECTION Disinfection is a key operation in any water supply. Here we emphasise the potential of using UV light as a potentially important and realistic opportunity to meet the challenge of pathogens in the water. 5.4.1 Disinfection technology Eliminating harmful organisms in the water is essential to protect people’s health. In water disinfection pathogenic microorganisms are deactivated or killed. Pathogens cause waterborne diseases such as cholera, polio, typhoid, hepatitis and several other bacterial, viral and parasitic diseases. Naturally it is of the utmost importance to substantially reduce the total number of viable microorganisms in the water. Disinfection can be achieved by using either physical or chemical disinfectants. The most common physical disinfectants are ultraviolet (UV) light, electronic radiation and heat. Common chemical agents for disinfection are chlorine (Cl2), chlorine dioxide (ClO2) and ozone (O3). In municipal water supply systems chemical inactivation of microbial contamination in the raw water supply is commonly used as one of the last steps to reduce pathogens in drinking water. Traditionally, chlorination is widely used for disinfecting water supplies in most western countries. For small water flow rates (household to village size) the primary treatment methods are ozone, UV radiation and chlorine. Techniques such as filtration may remove infectious organisms from water. However, filtering is no substitute for disinfection. Downloaded from https://iwaponline.com/ebooks/book-pdf/520710/wio9781780409443.pdf by IWA Publishing user