Successful Completion of a Uni-Directional Flushing Program in Florida

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1 Successful Completion of a Uni-Directional Flushing Program in Florida FWRC Palm Beach County Convention Center April 6, 2009 C. Robert Reiss, Ph.D., P.E.

2 Agenda Reasons For Action In Melbourne Investigations Conducted Traditional Flushing vs. UDF UDF Program Approach Water Quality Improvements Lessons Learned

3 City Water System Serves approximately 150,000 customers Two water treatment plants 5.0 MGD brackish groundwater reverse osmosis 20 MGD ACTIFLO surface water treatment plant (Lake Washington) 600 miles of distribution system piping Significant unlined, metal pipe

4 Reason for Concern Significant Increase In Customer Complaints Immediate Attention Level Reached (AWWARF) Complaints > 2% of Accounts Customers Contacting Council Members

5 Water Quality Investigation Team Reiss Engineering Frazier Engineering Dr. Marc Edwards Virginia Tech Scope Developed Enhanced Customer Complaint Database Evaluated Source of Red Water Treatment Facilities Distribution System Pipe Materials and Age Distribution System Hydraulics Distribution System Water Quality

6 Customer Complaint Database Customer Complaints Paper forms Limited entry into Excel Difficult to map Enhanced Customer Complaint Database MS Access-based, linked to GIS system Pull-down menus for customer service personnel to use Enhanced Questions Water Color Presence/absence of particles Presence/absence of low pressure Summary tables/plots Geographically Identified

7 Customer Complaint Database

8 Customer Complaints Conclusion Majority of Complaints (74%) from Red Water Complaints From Aug 2006 June 2007

9 Recommendations Increase finished water alkalinity (for increase in LSI and buffering capacity) Modify ammonia addition procedures to minimize nitrification Perform free chlorine burn Perform unidirectional flushing of distribution system

10 Historical Flushing Practices Standard Procedure: Respond To Customer Complaint By Performing Localized Flushing One Crew Was Dedicated Limited Effectiveness Of Localized Flushing

11 Localized Flushing Pros: Easy to complete Reduces retention time (water age) Partial debris removal occurs Addresses specific area of concern Cons: No valves manipulated Lower flushing velocity High water volume required Sediment may remain in pipe, disturbed, and cause more complaints

12 Unidirectional Flushing FDEP Requires Formal Flushing Program F.A.C Always Flushing From A Clean Source Source Of Water From Only One Direction (Flow From Branch Pipelines Isolated) High Velocities Scour Pipes & Remove Debris Build-up Lower Overall Water Usage

13 Melbourne Flushing Water Usage MG/month Reactionary Flushing Water Quality Flushing UDF (Worst Case)

14 UDF Program Approach Hydraulic Modeling Field Location and Assessment of Valves and Hydrants Flushing Maps Public Notification System Flushing

15 Hydraulic Modeling Hydraulic Model was updated and calibrated Service area divided into 340 Zones UDF modeling performed using Infowater UDF Software by MWH Soft Source of Valve and Hydrant Data City Atlas Maps Developer As-Builts Available GIS Data Institutional knowledge of City line crews pix

16 Hydraulic Modeling System Analyzed To Ensure Flushing From A Clean Source Sections Of Pipe Grouped Into Zones Branch Flows Isolated Pipe Runs Modeled To Achieve High Velocity

17 Hydraulic Modeling

18 Hydraulic Modeling Zones assigned to discrete areas A total of 340 Zones created within the service area

19 Field Location & Assessments City Contracted Field Services Provider WACHS Utility Services Geo-Location GPS Coordinates Collected For Each Asset Assessments Valve Boxes Cleaned Out & Raised (If Necessary) Valves Inspected & Exercised Hydrants Inspected & Exercised

20 Geo-Location & Assessments Valve Data Collected During Assessments Number of Turns Surface Cover (Grass or Asphalt) Maintenance Issues Found Closed Broken Stem, Spins Free Op-Nut Missing Hydrant Data Collected During Assessments General Condition Maintenance Issues (Leaks, Hard To Open)

21 Geo-Location & Assessments CHALLENGE # 1 ISSUE Maps Produced As Output From Modeling Software Were Not Geographically Accurate Large Number of Valves Not Located SOLUTION REI Manually Located Each Asset On City Atlas Maps CONSEQUENCE Additional Engineering Required RESULT Increased Production Rate Of Field Crew

22 Geo-Location & Assessments CHALLENGE # 2 ISSUE Located Valves Identified As Inoperable (Required Maintenance or Paved Over) SOLUTION Re-engineer Sequences To Select Alternate Isolation Valves CONSEQUENCE Additional Engineering And Field Crew Time RESULT Required Valves Necessary For UDF Located & Assessed

23 Public Notifications Initial Notifications via US Mail (2 weeks Prior To Flush) Website With Color Coded Flushing Schedule Street Signs (1 Day Prior To Flush) Customer Telephone Hotline

24 Public Notifications Flushing Schedule on Website

25 Public Notifications Example of Street Sign

26 System Flushing Flushing Maps Provided To Field Crews

27 System Flushing Water Samples Obtained Before And Two Weeks After Flushing Iron Concentration Chlorine Residual Turbidity Flushing Performed For Calculated Time Duration Additional Flushing Performed If Necessary White Bucket Test

28 Water Quality Improvements Overall Average Results From Sampling 77% Drop In Iron Concentration 57% Drop In Turbidity 15% Increase In Chlorine Residual Water Quality Complaints Dropped 90%: 53 complaints per month (2007) 13 complaints per month (2008) 5 complaints per month (first quarter 2009) City Council Members are not receiving phone calls

29 Lessons Learned Knowledge Of Valve And Hydrant Locations Is Essential In Modeling And Mapping Preparation Location And Assessment Of Valves And Hydrants Prior to Modeling Is More Efficient But More Costly Non-functional Valves Cannot Be Utilized And Will Lead To Additional Engineering And Location Efforts Many Notification Mailings Returned By Postal Service. Door Hangers May Be More Effective UDF Is Effective, Uses Less Water, And Has Better Results Than Localized, Reactionary Flushing

30 Thank You Orlando Tampa Winter Haven Carlsbad Nassau