Concepts of Drinking Water Protection in a Karstic Area of Switzerland

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1 Concepts of Drinking Water Protection in a Karstic Area of Switzerland KrK, Dr. Adrian Auckenthaler Swiss Federal Office of Public Health

2 Contents Problem of drinking water production in karstic areas Overview of concepts Groundwater protection in karst Water management Drinking water treatment Food safety management systems Summary and Conclusion 2

3 Problem of Drinking Water Protection in Karst The main problem is microbial contamination of spring water in combination with inadequate groundwater protection and failures in drinking water treatment. In complex systems it is difficult to get the important information to understand the origin of contamination, changes in raw water quality, to define the appropriate surveillance and treatment steps in drinking water treatment and finally to build up a food safety management systemthat brings together all the above aspects. Enterokokken E. coli Trockenwetter Regenereigniss Campylobacter positiv VTEC positiv Rotaviren 3

4 Three Linked Concepts of Drinking Water Protection Food Safety Management System Groundwater Protection Water Management Drinking Water Treatment Established concepts for different kinds of aquifers. Common are 3 protection zones S1 to S3. S2 is responsible for filtration of microorganisms. Dimension of S2: 10 days of groundwater flow or distance of 100 m. Surveillance of water quality with online measurable parameters (discharge, turbidity, particles el. conductivity). Rejection of water intake when the water quality is bad. Last step in drinking water protection. Knowledge out of the first two "columns" allow to evaluate the most appropriate treatment. Control of the treatment process. 4

5 Groundwater Protection 5

6 Groundwater Protection in Karst Area EPIK Field mapping Epikarst Field mapping protective Layer Field mapping infiltration Evaluate development of karst system 1. Four criteria, E, P, I and K 3. Delineation of protection zone 2. Calculation of safety factor F 6

7 Study Area Röschenz, Lützel Spring 7

8 Discharge and Microorganisms 5000 Discharge [L/min] Mai.99 Nov.99 Mai.00 Nov E. coli / 100 ml Enterokokken / 100 ml HPC / ml CFU Jan 95 Jan 96 Jan 97 Jan 98 Jan 99 Jan 00 Date 8

9 Hydrogeology / Tracer Tests Fleury,

10 Modelling Discharge fast Input slow Input Particel P P ETP fast flow V 5 fast flow V 6 intermediate flow slow flow V 1 slow flow V 2 V 7 Schüttung [m 3 /d] Messung langsamer Abfluss Überlauf schneller Abfluss Summe V 8-14 Spring Datum 10

11 Delineation of Groundwater Protection Zones 11

12 Water Management 12

13 Mikrobial Contamination in Spring Water E. coli, Enterokokken [CFU/100 ml] Niederschlag [mm/h] Datum im Jahr 2000 E. coli Enterokokken Niederschlag 13

14 Combination of Different Parameters 14

15 Water Management for Karst Springs How long is the time gap from beginning of precipitation to the quality change at the spring? Which parameter raises first? What is the extent of the contamination? Which parameter showes the end of contamination? How long does it last from the end of precipitation to the end of contamination? What amount of precipitation is needed for a quality change at the spring? How many peaks arise on one peak in precipitation? Is there a online measurable parameter that indicates microbial contamination? 15

16 Drinking Water Treatment UV Chlorine Chloric Gas Chlorinedioxid Ozon Sand Filter Activated Carbon

17 Adaption of Drinking Water Treatment to Aquifer Type Surface Water Multi Step Treatment Artificial Groundwater Recharge Bad Quality Flocculation Sedimentation Filtration Oxidation Disinfection Activated Carbon Ionexchange Softening Neutralizing Groundwater One Step Treatment Disinfection Distribution Network 17

18 Ct Values of Chlorine and Ozone Mikroorganism Chlor [mg/l* min] Chloramin [mg/l* min] Chlordioxid [mg/l* min] Ozon [mg/l* min] 23 # 0,5-0,6 Giardia lamblia # 0,53 1,4 # C. parvum 1440 >120 >5 E. coli 0,034-0, ,032-0,05 Streptokokki 0,17-0,84 Polio 1 Virus 1,1-2, ,4-0,75 0,02 1,2 0,012-0,04 0,009 0,2-6,7 0,1-0,2 Rotavirus 0,01-0, ,2-2,1 0,006-0,06 0,006-0,06 Norovirus

19 Food Safety Management System Karst Ausgangslage Water Quality / Wasserqualität Fissure Kluft River-GW Fluss-GW- Interaction Infiltration Gravel Lockergestein Aquifer Raw Rohwasser Water TW-Aufbereitung Drinking Water einstufig Treatment - log Reduction log Reduktion durch Drinking Aufbereitung Water Treatment Quality Qualitätsziel Target Drinking Trinkwasser Water Aquifertyp / Systemkenntnis QS / technische Systeme Aquifer Type / Technical System Fli di / Z i li h E i kl 19

20 Understanding Raw and Drinking Water Quality Raw Water Treatment Drinking Water Rohwasser Wasseraufbereitung Trinkwasser A ohne Aufbereitung Without treatment Prozess beherrscht Process controlled or oder B E X log Reduktion Prozess beherrscht Process controlled or oder Daten EAWAG C F Prozess nicht beherrscht Process not controlled D ohne Aufbereitung Without treatment Prozess nicht beherrscht Process not controlled 20

21 Summary and Conclusion For drinking water protection different concepts have to be considered: groundwater protection, water management and drinking water treatment. These concepts must be adapted to the specific circumstances of a water supply. Detailed knowledge of system behaviour is the key to implement the three concepts. Only with this knowledge optimal food safety management systems in water supplies can be established. In food safety it is necessary to have all processes controlled what implies online measurement of specific parameters. When we reach to bring together the environmental part of water protection and the requirements of food safety we can produce a good drinking water. 21

22 Thank You! 22