Biological stability parameters in operational practice

New methods for determining and predicting biological stability developed since 2010 are applied less often in daily drinking water practice than are the previously existing older methods. This, despite the fact that the new approach enables the derivation of a predictive value. A scientific paper in a pertinent international peer-reviewed journal would help broaden the acceptance for the new methods and derived guidance values. A workshop organised for the water sector will also contribute to this effort.

Not yet always applied

Since 2010, new predictive biological stability methods have been developed within the Joint Research Programme of KWR and the water utilities. These involve the BPP test, AOC-A3, CBM and PHMOC determination after hemoflow. In addition, a broad national research project was conducted (37 sites: 23 groundwater, 14 surface water) with a varying level of regrowth. The study’s results were used to derive guidance values for the clean water, which are predictive of high counts of HPC22 and Aeromonas in the distribution system.

Nonetheless, the new biological stability parameters and the derived guidance values are applied less often in daily drinking water practice than the old biological stability parameter AOC P17/NOX. One possible reason is that with the application of the new method a problematic regrowth occurred in the distribution system at a few production sites; so that further discussion is needed on the application and/or potential associated drawbacks. Moreover, the new methods have as yet not been published in an international peer-reviewed scientific journal.

Scientific publication and workshop

Resolving the above-mentioned problem areas could help create greater national and international acceptance for the new methods and the derived guidance values. The results achieved in this area in earlier Joint Research Programme projects will therefore be brought together in a single scientific manuscript for submission to a pertinent peer-reviewed journal. In addition, we will organise a workshop in which to discuss this subject with the Dutch and Flemish drinking water sector. During the workshop the new methods will be presented, including their application in daily drinking water practice. The workshop will also be used to draw up a wish-list of the drinking water sector regarding this subject. Based on this input, Joint Research Programme projects on biological stability can be further elaborated.