Drinking Water Treatment Technology- Challenges in Developing Countries Jessen George and Suriyanarayanan.S Department of Water and Health, Faculty of Life Sciences,JSS University, SS Nagar, Mysore – 560015 Corresponding Author: sunsjk@jssuni.edu.in The structure and functions of drinking water systems are depending on natural conditions, water demand and available economic resources. Although drinking water systems are commonly described as supply chains built up by three main sub systems: raw water, treatment process and distribution. The use of conventional water treatment processes becomes increasingly challenged with the identification of more and more contaminants, rapid growth of population and diminishing availability of water resources. In water treatment, among the most important developments are the establishment of the possible link between halogenated disinfection by-products (DBPs) and cancers, and the recent outbreaks caused by Giardia cysts and Cryptosporidium oocysts. Three emerging treatment technologies, including 1. membrane filtration Technologies ( RO, NF, UF and MF) 2. Advanced oxidation Technologies (Ozonation, Ozone -hydrogen peroxide (peroxone) and Ozone - UV radiation). 3. UV irradiation hold great promise to provide alternatives for better protection of public health and the environment. The Status of Urban water systems and Sanitation in India: In India, the major source and supply of drinking water to urban areas is dependent on surface water. Most of the water treatment plants in India adopt modifications to the conventional water treatment systems consisting of aeration, chemical coagulation, clari-floculation, sedimentation, filtration and disinfection. Conventionally, management and operations of a water treatment plants (WTP’s) were based on monitoring treated water quality parameters and to compare to the regulatory requirements. The importance of continues monitoring is a critical parameter to evaluate the performance before and after treatment unit of concern water treatment plants. Most of the developing countries like India facing the problems of high population density increase in solid waste generation, improper water supply and sanitation. It is estimated 72 % of Indian’s still lack access to safe drinking water and improves sanitation. At present, access to drinking water in urban areas of India is severely constrained (UNICEF, 2013). The status of municipal tap water supply in India about, 70.6 % of urban households use tap water for drinking, of which 62.0 % is treated and 8.6 % remains untreated (UNICEF, 2013). In India 85% of urban population has access to drinking water but only 20% of that water meets the minimum health and safety standards. The challenges of Advanced treatment technologies in developing countries become very cost-competitive, largely owing to the stricter regulatory requirements and the advances in equipment manufacturing. References: David McKenzie and Isha Ray., 2009. Urban water supply in India: status, reform options and possible lessons, Water Policy., 11, 442-460. UNICEF, FAO and SaciWATERs. 2013. Water in India: Situation and Prospects. WHO and UNICEF, 2012. Progress on drinking water and sanitation. Joint Monitoring Program Report (JMP). 1211 Geneva 27, Switzerland. WHO, 2011. Guidelines for Drinking Water Quality, 4th Edition, World Health Organization, Geneva. WHO, 2004. Guidelines for Drinking-Water Quality, 3rd Edition. World Health Organization, Geneva. ABSTRACT Water treatment technologies have improved over the past few centuries to protect public health from pathogenic organisms and chemicals. The provision of safe and adequate drinking water supply to the urban population is one of the major challenging tasks in many developing countries. Due to increasing population growth, increasing pollution and poor water management practices, fresh water resources are becoming scarce in many developing countries. As more than a billion people on this earth have no access to potable water that is free of pathogenic organisms, technologies that are cost effective and suitable for developing countries must be considered. Implementers of certain water treatment technology for a developing country have the choice to use different technologies to treat a contaminated water source. The contamination in a water supply is highly dependent upon the source of the water and the material that has been picked up by the water stream. In India most treatment plants adopt modifications to the conventional water treatment systems consisting of aeration, chemical coagulation, clari-floculation, sedimentation, filtration and disinfection. Nowadays many pathogenic organisms such as Cryptosporidium and Giardia which highly resistant to chlorination process. Generally the performance of the water treatment plants was based on the quality of treated water and to compare to the regulatory requirements. The importance of continues monitoring is a critical parameter to evaluate the performance before and after treatment unit of concern water treatment plants and also there is a need for up-grading the water treatment method in many developing countries. INTRODUCTION Access to safe drinking-water is essential to health and a component of effective policy for health protection. And also it is important as a health and development issue at a national, regional and local level. Improving access to safe drinking-water can result in tangible benefits to health (WHO, 2004). The provision of safe and adequate drinking water supply to the urban population is one of the major challenging tasks. The urban water system comprises both drinking water and waste water systems. An urban water systems it requires large amount of water. Hence urban planning and development are becoming more stressful due to the fact of growing competition of water which has leaded an increasing conflict of demand. Nowadays, the importance for water supply and sewage treatment for urban sanitation is well recognized. The increase of urban population and expansion of urban areas affects the urban water system. The rate of urbanization and urban slum growth in developing countries especially in Asia, Africa, South America and are estimated to be increasing and higher than the rate of urban infrastructure and services provision (WHO, 2012 and UNICEF, 2012). Due to increasing population growth, increasing pollution and poor water management practices, fresh water resources are becoming scarce in many developing countries. On the contrary, providing safe and sufficient drinking water and proper sewerage system remains as the challenging tasks for many developing countries particularly so, in urban areas. With the increasing scarcity of freshwater resources that are available to agriculture, the use of urban wastewater in agriculture has increased, especially in arid and semi-arid countries. Ensuring environmental sustainability, for example, demand adequate treatment and disposal of wastewater to contribute to better ecosystem conservation and less pressure on scarce freshwater resources. Drinking Water Treatment Technology: Conventional Treatment Method V s Advanced Treatment Methods: