The quality of drinking water is a powerful environmental determinant of health. Drinking water quality management has been a key pillar of primary prevention for over one-and-a-half centuries and it continues to be the foundation for the prevention and control of waterborne diseases. Water is essential for life, but it can and does transmit disease in countries in all continents-from the poorest to the wealthiest. Millions of people are exposed to unsafe levels of chemical contaminants in their drinking water. This may be linked to a lack of proper management of urban and industrial wastewater or agricultural run-off water potentially giving rise to long term exposure to pollutants, which can have a range of serious health implications (URL 1).Selecting the appropriate treatment process is a critical step in providing safe, reliable, good quality drinking water at a cost-effective price. There is a need for raw water quality data that cover an extended period sufficient to show seasonal and extreme events to make a sound decision on appropriate treatment processes. Before any process is finally selected, it is important to carry out treatability testing on the actual source water. All waters have subtle differences, and these can have a significant effect on process selection and performance (Muntisov, 2005).Water treatment process selection is a complex task. Circumstances are likely to be different for each water utility and perhaps may be different for each source used by one utility. Selection of one or more water treatment processes to be used at a given location is influenced by the necessity to meet regulatory quality goals, the desire of the utility and its customers to meet other water quality goals (such as aesthetics), and the need to provide water service at the lowest reasonable cost (Logsdon et al., 1999). The choice of treatment operations depends on the quality and variability of the raw water source and the treatment objectives, which may vary for industrial as opposed to municipal needs. A thorough survey of the quality and quantity of all possible sources is the first and most important step for designing a water supply process. Comprimising the water survey can be proving to be very costly in the long run thorough payment for more complex and expensive treatment operations. Water treatment operations must be designed to handle the extremes in raw water quality variation to provide an acceptable product water at all times (Droste, 1997).As illustrated in Table 7.1, a summary of more common drinking water treatment processes, there are many treatment options available to the designer to achieve the desired water quality results.

Table 7.1. Most common drinking water treatment processes (Fulton, 2005)