Turbidity and UV-absorption are two important parameters to ensure the
quality of drinking water. At AquaPro in Berne SIGRIST presents its actual
instruments to measure these parameters.
Turbidity is caused in water by mineral or organic solid particles.
Studies have shown that there is a clear correlation between turbidity and
the number of bacteria in a water sample. The dangers posed by these germs
are made even worse by the fact that they can cling to solid particles and
thus survive disinfection with chlorine, chlorine dioxide, UV irradiation or
ozone. For these reasons, new guidelines call for limits below 0.2 FNU and
continuous monitoring of turbidity in drinking water treatment. This
requires exact, high resolution analyzers.
In early 2006 the new AquaScat family has been launched onto the market
setting a new standard with its maintenance free construction. The flagship
is the AquaScat WTM with a measuring span of 0 to 4000 FNU, a resolution of
0.001 FNU, non-contact measurement and automatic adjustment on demand. Also
the version HT shows a non-contact setup. With a reduced resolution of
0.1 FNU and the same span it is primarily thought for higher turbidities
e.g. in raw water applications. The scope is completed with the AquaScat P
with a closed flow cell for measurement under pressure. This version has
advantages for samples with high gas content or to optimise the sample flow.
With this selection, the AquaScat can cover all applications in potable
water treatment form really dirty river water with more than 2000 FNU down
to best filtrated pure water with 0.015 FNU. Main difference to the previous
model WTM500 besides the increased measuring span is the integration of
keypad and display as well as the significantly reduced weight and volume of
The UV-absorption at 254 nm reacts on humic substances, but detects also
other organic compounds as oils, aromats, solvents, etc. These substances
have to be removed e.g. by active charcoal filtration. Studies have shown
that, for most applications, a linear correlation exists between the
UV-absorption and DOC (dissolved organic carbon) values. This means that UV
absorption measurement provides a continuous on-line indication for trend
analysis of the DOC figure without time-consuming laboratory checks.
Additional applications are in monitoring of ozonisation and active charcoal
filtration, to survey a sufficient disinfection and reduction of organic
material. A continuous monitoring of raw and treated water allows an
optimized control of the treatment and ensures a constant quality of the
The ColorPlus is built to accommodate up to three different light sources
in the UV and VIS ranges. Depending on the required wavelength, a mercury
bulb (UV light) or up to three LED's (VIS light) are installed. The
ColorPlus can be calibrated in E/m, Hazen, EBC etc. A combined UV
absorption/ Hazen color measurement is possible, too. Like all SIGRIST
process instruments, the ColorPlus exhibits the high measuring stability and
accuracy afforded by the dual beam measuring method.
The scope is completed by particle counters and oil trace analyzers,
which can also help to ensure the quality of the potable water.
Products: AquaScat WTM |
AquaScat P |
AquaScat HT |
ColorPlus bypass |
ColorPlus in-line |