1. TZW Karlsruhe Prüfstelle Wasser The Influence of Water Treatment on Corrosion of Materials in Service Lines and Drinking Water Installations Josef Klinger TZW Karlsruhe TZW Karlsruhe Prüfstelle Wasser

2. Why to change the Water Treatment? Water quality problems New raw water resources Merger of small water utilities Corrosion problems – desalination Consumer complaints – central softening

3. TZW Karlsruhe Prüfstelle Wasser Central Softening Precipitation (NaOH, Ca(OH) 2 ) Addition of acids (cooling water) Ion exchange Membrane filtration (nanofiltration, reverse osmosis)

4. TZW Karlsruhe Prüfstelle Wasser Membrane Filtration

5. TZW Karlsruhe Prüfstelle Wasser Reverse Osmosis 1 Feed 3 Feed spacer 5 Membrane 7 Permeate header 2 Permeate4 Concentrate 6 Permeate spacer 8 Sealing to pressure pipe

6. TZW Karlsruhe Prüfstelle Wasser Example out of the Practice Raw water quality Hardness Corrosion Limit value

7. TZW Karlsruhe Prüfstelle Wasser Pilot Study for Water Treatment Version A Mixture of desalinated water and aeration Version B 100 % RO and stabilisation of desalinated water with CaCO 3

8. TZW Karlsruhe Prüfstelle Wasser Parameters of the Test Waters in the Pilot Plant

9. TZW Karlsruhe Prüfstelle Wasser Closed Loop Device for Corrosion Tests with Iron Pipes

10. TZW Karlsruhe Prüfstelle Wasser Corrosion and Iron Migration Rates

11. TZW Karlsruhe Prüfstelle Wasser Mechanical Stability and Iron Migration Rates

12. TZW Karlsruhe Prüfstelle Wasser Corrosion Rates with changed Water Quality

13. TZW Karlsruhe Prüfstelle Wasser Example of a Turner Diagram

14. TZW Karlsruhe Prüfstelle Wasser Metallurgical Structure of Duplex Brass Source: Wieland-Werke AG

15. TZW Karlsruhe Prüfstelle Wasser Metallographical Grindings of the test pieces Running Time: 220 Days

16. TZW Karlsruhe Prüfstelle Wasser Tempered Brass Material: CuZn40Pb2 Running Time: 220 Days Test Water 3 (100 % RO + stabilisation) Tempered Brass Material: CuZn40Pb2 Running Time: 220 Days Test Water 1 Tap Water with Inhibitor Metallographic Sections of the test pieces

17. TZW Karlsruhe Prüfstelle Wasser The new Treatment Plant

18. TZW Karlsruhe Prüfstelle Wasser Summary The influence of a changed water quality on corrosion processes was assessed in a pilot plant Corrosion assessment tools are available Treatment plant is in service since two years Corrosion processes are controlled as predicted Prediction based on pilot plant tests were successful