18 March 2009

Safe Drinking Water

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Clean drinking water is a basic requirement for a healthy life and the drinking water demand of an adult person is two litres a day. But worldwide over one Billion people do not have access to clean water

Worldwide the water supply sector is facing tremendous challenges due to global warming and climate change, urbanisation, and increasing water stress and pollution of raw water sources. The European research project TECHNEAU (Technology Enabled Universal Access to Safe Water) is meeting these challenges with international experts of the scientific world and the economic system. New water supply options, improved treatment and monitoring technologies, and safer and more sustainable operation of treatment and distribution systems are worked out to support amongst others one of the WHO Millenium Goals: to provide access to clean water to double the current number of people by 2015.

Clean drinking water is a basic requirement for a healthy life and the drinking water demand of an adult person is two litres a day. But worldwide over one Billion people do not have access to clean water and though Europe is meant to be a continent with flawless water supply also here about 120 Million people are lacking the access to good drinking water. Most of the water works in Europe are already established, but water treatment facilities and distribution systems are aging from year to year and can not always handle new emerging contaminants and pathogens. In addition, the operation routines of existing facilities are not always optimal in terms of safety, sustainability and cost-efficiency. Several diseases are known to be water-borne, and diseases like diarrhoea, hepatitis A, and typhoid fever can be transferred through drinking water. But also new emerging pathogens and contaminants are increasing.

Also Norway, which is known as a country crossed with lakes and where the drinking water supply consists of 90 percent treated surface water is not immune against these new challenges. Due to heavy rain falls and lack of efficient treatment barriers the parasites Cryptosporidium parvum and Giardia lamblia got access to the water supply system of Bergen just a few years ago, in 2004. Some 1.500 inhabitants came down with diarrhoea, and one person even died. In succession hereof the Norwegian communities focussed even more on risk and vulnerability analyses of their water supply systems. Thus, the Bergen incident has induced more focus on water source/watershed protection and optimal operation of water treatment facilities and distribution systems. Combined with the already since the late nineties known fact that parasites can not be inactivated with chlorine disinfection but with UV and to some extent ozone, there has been a significant increase in the application of water treatment technologies that provide a barrier also against parasites, and in alternative disinfectants to chlorine.

Within TECHNEAU Norwegian scientists searched after new utilizable water treatment methods. Dr. TorOve Leiknes from the Department of Hydraulic and Environmental Engineering at NTNU and his research team developed amongst others a new three-way filtration method, called the OBM-process. “O” standing for the ozone filtration, during which ozone gas is added to the raw water in order to inactivate bacteria, parasites and viruses. The second step is the “B”io-filtration, where bacteria feed on the organic matter, part of which is made biodegradable by the ozone. Finally the third and last step is the “M”embrane-filtration – one of the most recent and innovative methods. The membranes act like a very fine net, with pores so small that they can capture particles in the micro- and nanometer range, i.e. micro, ultra and nanofiltration systems.

Besides the development of new treatment technologies, one the other eight work areas of TECHNEAU is addressed to the modelling and improving of existing supply systems. Dr. Bjørnar Eikebrokk, chief research scientist within the SINTEF Building and Infrastructure department in Norway was also head of the external evaluation committee which analysed the Giardia accident in Bergen. He is concerned with the operation of existing water treatment facilities. With optimal operation routines, water quality, cost-efficiency and sustainability are secured. A sub-optimal operation may compromise public health. The different water treatment methods have to be selected and operated in accordance with the raw water quality. Lake Jonsvatnet for example is the drinking water source for some 170.000 inhabitants in Trondheim and some of the adjacent communities. Its water work VIVA is now being upgraded with an UV disinfection to ensure an efficient inactivation of parasites like Giardia and Cryptosporidium.
In the neighbouring community Stiørdal the raw water quality is not as good as in Trondheim. Some 15 years ago the removal of natural organic matter (NOM) by coagulation and flotation-filtration was introduced. This process is based on the addition of a coagulant that destabilize small particles in the water, thus making them separable by flotation and filtration. Through flotation and filtration the formed particle aggregates (flocks) are separated from the drinking water. For TECHNEAU Dr. Bjørnar Eikebrokk is studying how existing treatment facilities can be optimized in order to provide good water quality, efficient removal of pathogens and other constituents like NOM and particles, minimum use of resources (e.g. chemicals, gases and energy) and a minimal slugde production.

The overall approach of TECHNEAU, which consists of 35 partners from 15 countries, will enable the end-users to make knowledge-based choices, appropriate to their own circumstances and constraints, for cost-effective and sustainable source-to-tap solutions. The aim of the researchers, technology developers and scientists of TECHNEAU is to supply people worldwide with safe and high quality drinking water that has the trust of the consumer.

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