Fortunately, the water level of the August flood in Switzerland receded faster than in New Orleans. Even if some repairs to damaged buildings and infrastructure facilities will still take months, the return to daily routines has been rapid for most. For those still affected, we hope that normalcy will return quickly with as little loss as possible.
We have been alerted to reports about hazards to drinking water caused by unprocessed waste water and pollution due to heating oil that has leaked into the lakes from which many communities draw their drinking water. Those with foresight have installed a measuring device at the water treatment input point that continually checks for oil traces and organic contamination.
But it is not only surface water that is affected. When there is flooding and raised ground water levels, contamination that is not usually present may also be evident in ground water, especially in bank filtrate. After the flooding in 1999, high bacterial counts were found in the ground water wells near the Limmat River effluent in Zurich, even though the turbidity value had not risen or risen very little. There was, however, a clear increase in the spectral absorption coefficient, or UV absorption value, and returned to normal only after several weeks. This was probably due to changes in the microstructures of the bank sand layers that were disturbed by the increased ground water currents. Particularly when it comes to ground water wells, a UV absorption measurement can provide added certainty that water quality is assured.
SIGRIST photometers reliably measure turbidity, coloration, UV absorption, oil traces and particle count in drinking water and thereby help to ensure unquestionable quality and optimal process handling during treatment.