| All water
sources contain naturally occurring bacteria,
the majority of which are harmless to humans
and easily removed through traditional disinfection
methods.
Surface waters such as lakes,
reservoirs, rivers and streams are more susceptible
to microbiological contamination and are likely
to demonstrate seasonal variation with numbers
increasing after periods of rainfall or alteration
to the local land use.
 |
Portable
cryptosporidium sampling unit |
The presence of certain micro-organisms
can give a good indication of the quality
of a water. These include the group of organisms
termed coliforms.
Coliforms indicate fecal
contamination of the water source, typically
from animals grazing in the catchment area.
If there is a high number of these organisms
it indicates that the water supply has been
contaminated. The risk of infection from these
organisms is easily removed by the traditional
disinfection processes of chlorination and
ultra violet disinfection.
Of greater concern, although
a rare occurrence, is contamination of a water
source with either Cryptosporidium or Giardia
organisms.
Both of these organisms create
protective oocysts which are resistant to
traditional disinfection processes.
Cryptosporidium
is unaffected by chlorination and other traditional
methods, and can only be effectively removed
by micro-filtration or other more advanced
techniques
 Giardia
is also resistant to traditional
treatment and again micro-filtration is required
to physically remove this organism.
Drinking Water Services
use a proven system, that incorporates a micro-filtration
part to the process to provide the necessary
protection against these organisms.
 |
Chlorine
dosing unit |
Chlorine dosing allows a
residual disinfection after the water has
travelled some distance through pipework.
UV is typically used as these
treatment plants are normally sited close
to the point of use.
|
