Truth-seeking mission at Onnen pumping station
A standard exceedence in the colony count – the number of viable micro-organisms in a given volume of water – right after the renovation of a pumping station. In 2013 this happens to Waterbedrijf Groningen. The water company calls on KWR to find out what lies behind the colony growth.
Waterbedrijf Groningen (WBG) renovates the Onnen pumping station. Changes are made to increase the site’s security of supply and to upgrade the technical installations. Following protocol, prior to putting the station back into operation, WBG tests the water quality. There are bacteriological problems. After intensive flushing, the colony count – the number of viable micro-organisms in the water – is successfully brought down below the standard. It is observed that something is stimulating regrowth. The company wonders whether the colony growth was caused by a newly-installed butterfly valve or originated in the treatment process.
“Even though the problem was solved, we wanted to be clear about what happened”
Learning from experience
“Even though the problem was finally solved, we wanted to be clear about what happened,” says Martin Leeuwerke, Sector Manager, Water Supply, at WBG. “What was the cause? We really wanted to learn from the experience for future reference.” The water company asks KWR to go on a “truth-seeking” mission. The researchers quickly get down to work and come to the conclusion that the most probable cause is that the treatment at times is insufficient. WBG is content with the clarity. “Naturally,” says Leeuwerke, “we wanted a quick explanation, and that’s what we got. The filters don’t need to be replaced, but by adjusting the flushing programme we can continue to guarantee good quality water.”
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Manager Industry, Wastewater & Reuse and Senior scientific researcher