Scientific data on levels of micro-organisms indicate that the concentration of coliform bacteria (i.e. e.coli), commonly found in surface waters, ranges from 105 (also expressed as log 5) per 100 ml for polluted stream water to 109 / 100 ml in raw sewage. Considering infectious levels of 103 for immune compromised people, the target effluent concentration after treatment should be less than 1/100 ml or a reduction of at least 8 log.
Cysts (i.e cryptosporidium and giardia) are the largest waterborne micro-organisms (3 - 6 micron) and occur in surface waters in a concentration of 10/L. They are highly infectious and the target effluent after treatment should contain less than 1/100L, equivalent to a 3 log reduction.
Since 1976 we know that not only ingested
bacteria can have serious health effects, but also if inhaled Legionella
Pneumophilia bacteria can cause a severe form of lung infection.
Conventional
methods as RO, UV treatment or chemical disinfectants only partly and
inadequately inactivate micro-organisms, as water temperature, pH,
turbidity
and other external factors, as well as the relative resistance of
micro-organisms to disinfectants, influence effectivity.
The Ster-O-Tap
![]() Bacillus subtilis |
![]() Cryptosporidium Oocysts |
![]() Escherichia coli (ecoli) |
![]() Giardia lamblia |
![]() Salmonella Typhi |
![]() Shigella Sonii |
![]() Enterococcus faecalis |
![]() Pseudomonas Aeruginosa |
![]() Vibrio Cholera |
Information regarding approximate infectious doses and size
may be gathered by selecting the desired image.
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