Membrane Technology

Specialist for Hollow Fiber Membranes and Membrane Cartridges.

About Water

The consumption of water is one thing we all have in common. We all need it to survive. Water naturally spreads bacteria. Waste water from households, institutions and industry is collected at water treatment installations via sewers. It is then treated and discharged to surface water (canals and rivers). Together with the water from deeper strata in the ground, it is treated again to be supplied back to the consumers. In spite of the great care that is taken in the water treatment process, the recycled drinking water cannot be made fully bacteria free. Water utilities follow the standard of a maximum of 100 coliform bacteria per litre of the drinking water supplied, which is normally a safe concentration. However, water pipes in larger buildings such as hospitals, institutions and hotels often run for several kilometres and can include sections with stagnant or slow-flowing water. These parts can develop biofilm, a slimy deposit on the pipe wall which is a natural nutrient medium for bacteria.

Under the right conditions (25 to 50 °C), bacteria can multiply extremely quickly. What entered the water pipe as a harmless concentration can reproduce within a few hours to reach a level that will cause illness, especially when this involves pathogenic species such as E. coli or Legionella pneumophila.

Similarly, our water supply is exposed to the consequences of all kinds of assaults on the environment. Chlorine, which is added to eliminate micro-organisms, breaks down into the hazardous trihalomethanes, which can lead to sharply decreased thyroid function, particularly among children. Moreover, there are regular reports of increased levels of VOCs (volatile organic compounds), pesticides and herbicides in the groundwater. In recent years, there have been increasing reports that hormones and residues of medicines are being found in the water. Your water company cannot handle this high variety of pollutants. If we do not purify the water, the body will do this, but often at the expense of our health.

Bottled water, a disaster for man and the environment

More and more people use bottled water as drinking water. This is often because tap water is not trusted or because special qualities are expected. This is a myth, because bottled water is often worse than tap water. Moreover, the water is perishable after the bottle has been opened. It may quench thirst, but bottled water is a disaster for man and the environment. More than 150 billion liters is packaged in PET bottles each year, requiring > 3 million tons of plastic. The production of the bottles and their transportation, both unfilled and filled, requires huge consumption of energy and raw materials and of course gigantic emissions of CO2.

In a large part of the world the PET bottles are not recycled after use, resulting in a dramatically growing waste mountain. Bottled water is a redundant product. The money, the energy and effort would better be spent on improving the water facilities of those who have chronic shortage.

Environmental impact of discarded water bottles

  • More than 200 million water bottles are discarded worldwide every day.
  • It takes 200 ml of oil to produce a plastic bottle.
  • The equivalent oil of 10,000 bottles would keep a car going for a year.
  • Massive amounts of greenhouse gases are produced from manufacturing plastic bottles.
  • Millions of liters of fuel are wasted every day transporting bottled water around the world.
  • Above all, virtually every independent study on bottled water shows contamination by bacteria and/or synthetic chemicals.

Micro-organisms in water

Scientific research has shown that the normal concentration of coliform bacteria (e.g. E. coli) in surface water varies between 105 per 100 ml (also expressed as log 5) and 109 per 100 ml for sewer water. Considering that a dose of only 103 is enough to cause an intestinal infection in people with a weak immune system, no more than 1 per 100 ml may remain in treated water, or a reduction of at least 6 log (99.9999%).

Cysts (such as Cryptosporidium and Giardia) are the largest micro-organisms that occur in water (3 – 6 µm). They are found in surface water in concentrations of 10 per litre. They are very infectious and must not be present in water after treatment, which requires 3 log (99.9%) removal. The concentration of enteroviruses (e.g. polio and rotaviruses) in surface water is estimated at 102 -103 per litre. It is generally accepted that drinking water may not contain viruses (< 1 per 100 litres). The reduction must be at least 4 log (99.99%).

These purification standards are established in the various water supply decrees in Europe. Since 1976 we have known that ingested bacteria are not the only serious threat to our health. Bacteria (Legionella) that are inhaled with water vapour can cause a serious form of lung infection.

So far, we have been able to effectively treat illnesses that are caused by bacteria with antibiotics. Slowly, bacteria have developed resistance against this with the so-called NDM 1 gene, which neutralises the effect of all known antibiotics. This gene, which makes bacteria resistant, is found in bacteria that cause dysentery (E. coli), for example.