HOW WATER QUALITY SENSOR DATA CAN HELP REDUCE LEAKAGE

Editor's Notes

1. The turbidity trace from 27th November to December 2nd is “business as usual”. 0.2 to 0.5NTU An event on 2nd December provoked a change in the turbidity. There was a very big increase in the frequency and magnitude of turbidity peaks. On the 18th of December there was a burst event that caused a massive turbidity spike. The erratic behaviour of the chlorine trace was provoked by rapid pressure fluctuation prior to the burst. 
2. The turbidity trace from 27th November to December 2nd is “business as usual”.  0.2 to 0.5NTU An event on 2nd December provoked a change in the turbidity. There was a very big increase in the frequency and magnitude of turbidity peaks.  On the 18th of December there was a burst event that caused a massive turbidity spike. The erratic behaviour of the chlorine trace was provoked by rapid pressure fluctuation prior to the burst. 
3. The turbidity trace from 27th November to December 2nd is “business as usual”.  0.2 to 0.5NTU An event on 2nd December provoked a change in the turbidity. There was a very big increase in the frequency and magnitude of turbidity peaks.  On the 18th of December there was a burst event that caused a massive turbidity spike. The erratic behaviour of the chlorine trace was provoked by rapid pressure fluctuation prior to the burst. 
4. The turbidity trace from 27th November to December 2nd is “business as usual”.  0.2 to 0.5NTU An event on 2nd December provoked a change in the turbidity. There was a very big increase in the frequency and magnitude of turbidity peaks.  On the 18th of December there was a burst event that caused a massive turbidity spike. The erratic behaviour of the chlorine trace was provoked by rapid pressure fluctuation prior to the burst. 
5. This data shows free chlorine values recorded at pressure reducing valve chambers down a trunk main. The trends and profiles are almost identical and it is easy to calculate the time taken for the water to move from one location to another. This time information can be used to calculate velocity and then flow. Flow differences can identify possible leaks. E.g. 50Meg into the system, if the flow between one pair of chlorine sensors is not “correct” it could be because of a leak. 
6. If there is a discrepancy between the flow meter flow and the chlorine monitor virtual flow this need investigating.  It is possible that the diameter of the pipe is wrong, for example if the GIS indicates that the pipe internal diameter is 8” but the only way to make the flow numbers to agree is to use a diameter of 7.8” this could indicate that the pipe has a 0.1” layer of biofilm. 
7. If there is a discrepancy between the flow meter flow and the chlorine monitor virtual flow this need investigating.  It is possible that the diameter of the pipe is wrong, for example if the GIS indicates that the pipe internal diameter is 8” but the only way to make the flow numbers to agree is to use a diameter of 7.8” this could indicate that the pipe has a 0.1” layer of biofilm. 
8. If there is a discrepancy between the flow meter flow and the chlorine monitor virtual flow this need investigating.  It is possible that the diameter of the pipe is wrong, for example if the GIS indicates that the pipe internal diameter is 8” but the only way to make the flow numbers to agree is to use a diameter of 7.8” this could indicate that the pipe has a 0.1” layer of biofilm. 
9. The measure decay can be compared to the theoretical model. Bulk and wall decay can be calculated. If the wall decay changes with time it is another use of non invasive chlorine sensors being used to asses internal pipe condition. 
10. The measure decay can be compared to the theoretical model. Bulk and wall decay can be calculated. If the wall decay changes with time it is another use of non invasive chlorine sensors being used to asses internal pipe condition. 
11. The measure decay can be compared to the theoretical model. Bulk and wall decay can be calculated. If the wall decay changes with time it is another use of non invasive chlorine sensors being used to asses internal pipe condition. 
12. The measure decay can be compared to the theoretical model. Bulk and wall decay can be calculated. If the wall decay changes with time it is another use of non invasive chlorine sensors being used to asses internal pipe condition. 
13. Was this a turbidity event with chlorine demand? One hypothesis is that the turbidity was caused by dislodged material that had a chlorine demand. Maybe biofilm? This would indicate that there was an increased risk of taste and odour issues due to organochlorine compound formation.  Another hypothesis is that the material caused a drop in pH which depress the chlorine reading. 
14. Was this a turbidity event with chlorine demand? One hypothesis is that the turbidity was caused by dislodged material that had a chlorine demand. Maybe biofilm? This would indicate that there was an increased risk of taste and odour issues due to organochlorine compound formation.  Another hypothesis is that the material caused a drop in pH which depress the chlorine reading. 
15. Was this a turbidity event with chlorine demand? One hypothesis is that the turbidity was caused by dislodged material that had a chlorine demand. Maybe biofilm? This would indicate that there was an increased risk of taste and odour issues due to organochlorine compound formation.  Another hypothesis is that the material caused a drop in pH which depress the chlorine reading. 
16. Was this a turbidity event with chlorine demand? One hypothesis is that the turbidity was caused by dislodged material that had a chlorine demand. Maybe biofilm? This would indicate that there was an increased risk of taste and odour issues due to organochlorine compound formation.  Another hypothesis is that the material caused a drop in pH which depress the chlorine reading. 
17. Was this turbidity event caused by material that did not react with chlorine. Fully oxidised manganese, iron, inert pipe lining? 
18. Was this turbidity event caused by material that did not react with chlorine. Fully oxidised manganese, iron, inert pipe lining? 
19. The pre event turbidity value is around 0.8NTU. A large but short lived event occurred Post event the NTU drop to around 0.3NTU 
20. The pre event turbidity value is around 0.8NTU. A large but short lived event occurred Post event the NTU drop to around 0.3NTU 
21. Chlorine plummets to zero too. Biofilm? And a lot of it?
22. Chlorine plummets to zero too. Biofilm? And a lot of it?
23. 20 minute off scale event
24. 20 minute off scale event
25. 20 minute off scale event
26. 20 minute off scale event
27. DAM 40 has historical discoloration and  taste and odour The Cl2 trends in 09 are following 40 trends so there is clearly a link. 
28. DAM 40 has historical discoloration and  taste and odour The Cl2 trends in 09 are following 40 trends so there is clearly a link.