Drinking Water Fluoridation in the News: Current Status and Proposals
Transcript of Drinking Water Fluoridation in the News: Current Status and Proposals
Contents
Introduction
Fire Hydrants
Aging Infrastructure
Active Leak Detection
Passive Leak Detection Passive Leak Detection with AMR
Comparison of Active and Passive Technologies
Conclusion
Introduction: Location
Albuquerque, New Mexico
Introduction: Issue
Drought conditions for at least past decade
Population increase of roughly 20%
Residents are being asked to conserve
So…
Albuquerque Bernalillo Water Utility Authority must reduce water losses as much as possible
Introduction: Challenge
Determine applicable strategies to reduce water losses in a way that:
Makes sense
Is economical
Is feasible
Fits within current operations
Water Audit
Water Supplied
Real Water Losses
5%
(Total Non-Revenue Water 18%)
Fire Hydrants
Prior to Study
14,121 Hydrants in distribution system
Estimated water loss 1% of total loss
Question: Should Repairing all Fire Hydrants Be a Part of a Strategic Water Loss Reduction Strategy?
Fire Hydrants
Study
All 14,121 Hydrants were searched for
Data collected on each one
Results
13,694 were found
416 were found to be leaking
Fire Hydrants
Water Loss Estimates
22 MG to 383 MG/Year
Some hydrants would be repaired w/o a FH program
Incremental savings: 10 MG to 180 MG/Year
Overall savings 0.5% to 1%
Fire Hydrants
Conclusion
Not worth the effort of a full FH survey
Should only survey the grid zones (1 mile square areas of the city) with majority of hydrants installed before 1970 and those manufactured by certain manufacterers
Could cut workload to a fraction of the area and still receive most of benefits
Aging Infrastructure
Infrastructure Study Results
2,500+ miles of pipe
5% of System is steel pipe ~60 years old & causes 50% of the breaks
Question: How Should Aging Infrastructure be Addressed as Part of a Strategic Water Loss Reduction Strategy?
Aging Infrastructure
Money available for pipe replacement
$1 - $3 million/year
Cost of 1 mile of pipe replacement ~ $500,000
Therefore, 2 to 6 miles/year could be replaced
Even at $3 M/Year could take almost 20 years to replace all steel pipe
Therefore, How to Decide??
Aging Infrastructure
Used Asset Management Approaches to Choose Pipe Segments with
High probability of failure
High consequence of failure
Aging Infrastructure
Probability of Failure factors Number of breaks
Age
Location (soil types, landfills)
Other known history
Consequence of Failure Critical customers
Hard to repair areas
High traffic corridors
Aging Infrastructure
Using this approach
10 years worth of pipe segments were identified for replacement
Early results show a reduction in pipe breaks from 50% to 35% of the breaks from steel pipe
Conclusion
A strategic replacement approach can reduce water loss from aging infrastructure
Active Leak Detection
Active leak detection involves listening to distribution system; crew systematically goes through the system listening to assets to hear leaks
Question: Should active leak detection be part of an overall strategy?
Active Leak Detection
Limited to one crew
Crew has additional duties
Had to obtain trust of repair crews; initially repair crews didn’t trust results
After some success, trust has increased
Active Leak Detection Conclusion:
Not yet big enough part of Strategic Loss Reduction
Being used mostly to find location of leaks called in by customers, rather than proactively looking throughout system for leaks
Passive Leak Detection
Passive leak detection involves installing devices on valves and/or meters. Devices listen for noise and report an alarm if noise is heard
Question: Should passive leak detection be part of an overall strategy?
Passive Leak Detection
Two types of devices were tested: Permalog and Zonescan
Passive Leak Detection Deployed on the same areas to judge results,
ease of use, time to deploy
Results: Time to deploy similar
Neither device found all leaks present (9 found that neither device found)
Both devices found “ghost leaks”
Conclusion: Zonescan was determined to be easier to use, however, a trained staff is a necessary component
Passive Leak Detection Integrated with AMR Technology Passive leak detection integrated with AMR
metering involves installing passive leak detection devices such that reporting occurs through the AMR system
Question: Should passive devices be installed with AMR as these devices are added to the system?
Passive Leak Detection Integrated with AMR Technology
Looked at Permalog units attached to AMR meters
Chose one small area to test
Initially, devices did not read properly
No leaks were reported for several months (no leaks or no reports???)
Passive Leak Detection Integrated with AMR Technology
Created leaks in fire hydrants to test devices
Did not register leaks
Two devices went into alarm mode, but no leaks were present
Conclusion: Devices are not yet worth the price to install along with AMR, given the results
Comparison of Active & Passive Leak Detection
Question: How do active and passive leak detection methods compare?
Comparison of Active & Passive Leak Detection Active better able to find house side &
hydrant leaks
Passive finds more “ghost leaks”
For one pass, active cheaper
Passive devices did not hold up well to field conditions (70% failed within 3 years)
Comparison of Active & Passive Leak Detection Both technologies require trained staff, skilled
technician (active even more so)
Desire to fix leaks that are found is essential; water only saved when leaks fixed!!!
Amount surveyed must match what can reasonably be repaired
Conclusion: Both practices can find leaks faster than waiting for them to surface
Conclusion
Strategic water loss reduction is very important
Program will include a variety of strategies:
Fire hydrant surveys
Replacement of aging infrastructure
Combination of active and passive leak detection
Additional approaches are still being investigated
Questions
Comments
Concerns
Heather Himmelberger, P.E. Director, NM EFC 1-505-924-7028 [email protected] http://nmefc.nmt.edu