Flow cytometry in drinking water research:
case-study Amsterdam
Marius Vital, Marco Dignum, Aleksandra Magic, Petra Ross, Luuk Rietveld and Frederik Hammes
marco.dignum@waternet.nl 2
Overview
• Waternet’s philosophy behind safe drinking water • Description of treatment steps
• Results from Techneau case-study Amsterdam 2009 • Future research interests
First watercycle company in The Netherlands
Waternet takes care of thewater cycle in Amsterdam and surroundings, including:
– Dikes and flood protection – Management of surface and
ground water
– Sewage system and waste water treatment
– Production and distribution of drinking water
Philosophy behind safe drinking water
The 5 rules of Peter Huck (prof @ University of Waterloo): 1. Protect the source
2. Good treatment 3. Good distribution 4. Monitor the quality
5. Ready for direct action
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Drinking water treatment Leiduin en Weesperkarspel
(LDN) (WPK)
Differences in the two watertypes
Tabel 1. Jaargemiddelde waarden van de voor dit onderzoek relevante waterkwaliteitsparameters van het reine water van Leiduin (LDN) en Weesperkarspel (WPK) (gemiddeld over 2007 ± 95% betrouwbaarheidsinterval; aantal vrijheidsgraden tussen haakjes)Parameter LDN WPK pH 8.17 ± 0.02 (51) 7.92 ± 0.03 (51) Chloride (mg.l-1) 87.9 ± 1.4 (51) 79.4 ± 1.0 (51) Sulfaat (mg.l-1) 48.4 ± 1.0 (25) 9.0 ± 0.7 (12) Bicarbonaat (mg.l-1) 166.7 ± 2.1 (51) 176.7 ± 1.2 (62) TOC (mg.l-1) 1.19 ± 0.08 (27) 2.89 ± 0.09 (50) AOC (µg ac-C.l-1) 6.4 ± 1.1 (11) 18.4 ± 3.5 (14)
Aeromonas spp. (cfu.l-1) af pomp 19 ± 8 (51) 390 ± 110 (81)
Aeromonas spp. (cfu.l-1) in de periferie
van het distributienet* 730 ± 280 (51) 8220 ± 1270 (237)
*Gemiddelde over 10 verst gelegen monsterpunten met verblijftijd groter dan 48 uur
10!
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rapid filter pre-treated water
rapid filter
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rapid filter
BAC rapid filter
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BAC rapid filter
reservoir Network (5x) BAC
rapid filter
pre-treated water ozonation PSF slow filter
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reservoir Network (5x)
BAC rapid filter
pre-treated water ozonation PSF slow filter
Parameters measured
1. FCM – intact cell counts
2. Cellular ATP
3. HPC / Aeromonas
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Stained bacteria
Capillary Laser Microscope lens
1000 10000 100000 1000000 10000000 tion poin t rapi d fil ter ised wate r ned wate r on fi ltrate king wate r ibuti on 1 ibuti on 2 ibuti on 3 ibuti on 4 ibuti on 5 F C M d ir e c t c e ll c o u n t (n /m L ) WPK LDN reservoir Network (5x) BAC rapid filter
pre-treated water ozonation PSF slow filter
Ozon dose
LDN: 0,35 mg O3/mg C WPK: 0,33 mg O3/mg C
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reservoir Network (5x)
BAC rapid filter
pre-treated water ozonation PSF slow filter
0 20 40 60 80 100 120 140 160 180 200 220 extr actio n po int rapi d fil ter ozon ised wate r softe ned wate r carb on fi ltrate drin king wate r distr ibuti on 1 distr ibuti on 2 distr ibuti on 3 distr ibuti on 4 distr ibuti on 5 A O C ( µ g /L ) WPK LDN AOC removal 62% 59%
reservoir Network (5x) BAC
rapid filter
pre-treated water ozonation PSF slow filter
1,0E+03 1,0E+04 1,0E+05 1,0E+06 1,0E+07 actio n po int rapi d fil ter onis ed w ate r ftene d w ate r rbon filtr ate inki ng w ate r strib ution 1 strib ution 2 strib ution 3 strib ution 4 strib ution 5 F C M ( c e ll s /m L ) 1,0E-01 1,0E+00 1,0E+01 1,0E+02 1,0E+03 A T P ( n g /L ) FCM ATP WPK
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reservoir Network (5x)
BAC rapid filter
pre-treated water ozonation PSF slow filter
1,0E+00 1,0E+01 1,0E+02 1,0E+03 1,0E+04 1,0E+05 extr actio n po int rapi d fil ter ozon ised wate r softe ned wate r carb on fi ltrate drin king wate r distr ibuti on 1 distr ibuti on 2 distr ibuti on 3 distr ibuti on 4 distr ibuti on 5 P la te c o u n t (c fu /m L ) 1,0E-02 1,0E-01 1,0E+00 1,0E+01 1,0E+02 A e ro m o n a s ( c fu /m L ) HPC25 HPC22 Aeromonas WPK
Summary
Actualbiomass Potentialbiomass
RSF - -Ozone -- ++ PSF + --BACF + --SSF - -DWDS 0 0
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Conclusions
• Flow cytometry and ATP are fast and easy, cultivation-independent methods for overall biomass estimation
• These methods correlate well and show the same pattern for both treatment plants
• In some cases, the methods are complementary
• Only a small fraction of bacteria can be cultivated; plate counts show inconsistent patterns
• Overall, production of hygienically safe and biologically stable drinking water without chlorine residual is possible
Operational issues
• Aeromonas control (BTO)• Rapid detection of Enterobacteria (Waterlab Noord) • Biofilm prevention in PE pipes
• Breakthrough of slow sand filtration
• Influence of temperature on biological stability and emerging pathogens (BTO)
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Future research interests
• Foodchain in an oligotrophic environment: what is biological stability?
• Understanding and preventing Legionella growth (BTO) • Does microbial corrosion play a role in pipe ageing?
• Relationship between particle sedimentation and bacterial growth