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Lenntech
Infectious
diseases caused by pathogenic bacteria, viruses and protozoan parasites are
among the most common and widespread health risk of drinking water.
People are
introduced to these microorganisms through contaminated drinking water, water
drops, aerosols and washing or bathing.
Some waterborne
pathogenic microorganisms spread by water can cause severe, life-threatening
diseases. Examples are typhoid fever, cholera and Hepatitis A or E.
 |
| Figure 1. Diarrhoea is an important symptom of many waterborne diseases. |
diseases. Often, diarrhoea is the main symptom (figure 1).
People with low
resistance, mainly elderly people and young children, are vulnerable to these
diseases as well.
No access to
clean drinking water
Worldwide, 1,2 billion people do not have
access to clean and safe drinking water, and 2,4 billion people lack
sanitation. Every year, 5 million people die of waterborne diseases.
Developed
countries
Most waterborne
diseases occur worldwide. In developed (western) countries, contagion is
prevented by drinking water purification and by hygienic measurements.
But even in developed
countries, people can fall ill from waterborne diseases. This is caused by
using insufficiently disinfected water, by implementing non-hygienic food
preparation and by insufficient personal hygiene.
Developing
countries
In developing
countries, waterborne diseases are a major problem which contributes to the
vicious circle that people are in.
In many
developing countries, there is a lack of medicine to treat ill people.
Vaccination is usually very scarce as well.
Many people
weaken because of waterborne disease and, as a result, are more susceptive to
other infections. Their physical capacity decreases and they cannot work and
provide their families with money and food.
A lack of
sufficient nutritional food weakens people, especially children, even further.
They become even more susceptible to diseases.
Children run
behind at school, because they cannot be educated when they are ill. Waterborne
diseases frustrate the economic development of many people.
The appearance of
HIV in developing countries makes more people susceptible to infectious
diseases.
During wars and
natural disasters (floods) many people are infected with waterborne diseases.
Diseases are
easily spread because water treatment and sewage no longer function or are
lacking completely.
To improve the
economic progress of developing countries, water contamination and spread of
infectious diseases must be handled. This is achieved through (drinking) water
treatment, sewage, waste and sewage water treatment and education on personal
and food hygiene.
Occurrence
of waterborne diseases
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| Figure 2: the number of waterborne diseases in the United States from 1971 to 1992 |
It is impossible to represent the number of waterborne microbiological infections (figure 2). This has several causes. Diseases are misdiagnosed or not reported.
Sometimes it is
difficult to demonstrate the source of a water related disease. Both swimming
in contaminated water and the microbiological or chemical quality of drinking
water can cause illness.
Disinfection
remains important
Groundwater
usually has a good microbiological quality, because it is prefiltered through
various ground layers. Those ground layers function as a natural filter;
microorganisms and other particles are removed when the water seeps down.
Afterwards, the
water still needs treatment, because not all pollutions can be removed
biologically. Groundwater can be contaminated by sewage water or waste water
pollutions.
Even when water
treatment is applied, one has to watch out for outbreaks of waterborne
diseases.
Water that is
used for drinking water purposes can be prepared from surface water,
groundwater or recycled water.
This water can be
contaminated by pathogenic microorganisms and other pollutants. Sufficient
disinfection is needed to prevent diseases.
New waterborne
diseases
Infection routes
change throughout the years. In the last twenty years a number of pathogenic
diseases have appeared, even in developed countries, that cannot be prevented
by traditional water treatment.
For example: in
1993 in Milwaukee, USA, 400,000 people fell ill from using drinking water that
was contaminated by Cryptosporidium cysts.
In the year 2000,
2.300 people fell ill in Walkerton, Canada, because of E. coli O157:H7.
Other pathogenic
microorganisms that can be found in drinking water are caliciviruses,
Heliobacter bacteria, Mycobacteria and Giardia Lambia.
Lenntech provides water
treatment solutions for all type of applications, from domestic equipment to
industrial turnkey plants up to 5000 m3/day.
Our wide
range of technologies and extended know-how in all water-related sectors will
guarantee you a cost-efficient solution meeting your water quality
requirements.
Lenntech deals daily with
clients from various origin: municipalities, water bottlers, hotels and resort
requiring safe drinking water for their visitors, farmers needing specific
irrigation water for their plants, but also industries like power plants, oil
and gas, chemical factories, requiring specific process water for their
equipment.
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