1. Separating Inflow Reduction From Infiltration Removal Using Simple Tools Frederick Bloetscher, PhD, PE Florida Atlantic University

2. For Florida:  Inflow  Stormwater discharged directly into sewers from roof drains and stormwater runoff  Infiltration  Groundwater that enters the sewer through defective pipes, joints, connections, & manholes  Inflow creates hydraulic issues and SSOs  Both overload collection systems & reduces treatment efficiency  Function of age

4. Symptoms of a problem: Sewer Higher than Water Sales?

5. Symptoms of a Problem Sewer Flows v. Rainfall We can see …..INFLOW!!!

6. Symptom Sanitary Sewer Overflow

7.  Sewer flow peaks during rain events.  The size of the storm event matters. A larger storm event will create more inflow.  During storm events, wastewater flow is linearly related to rainfall.  Based on an analysis of flow vs. rainfall graphs from pre and post construction activities inflow reduction will be calculated. Inflow

10. INFLOW Inflow

11. INFLOW Inflow BASEFLOW + INFILTRATION

12. INFLOW Inflow

13. Cover / Frame Inflow Frame / Chimney Infiltration Rain or Shine Water Table Inflow Solutions – Low tech Protocol – Seal Manhole Frame/Cone Connection

14. Sealing the Manholes Plus Correct Dish!!!

15. Smoke the System!!!

16. LDL Plugs for Cleanouts Broken or Removed

17. Results - LS 52 – Cooper City – Inflow Correction Only

18. Results - LS 53 Cooper City – Inflow Correction Only

19. Results - LS 54 Cooper City – Inflow Correction Only

20. Results - Dania – System

21. Community % Change (Pre Vs. Post) Dania Beach (2006 vs. 2009)-31.9% Cooper City (2011 vs. 2013)-62.8% Savings for Inflow Removal

22. Midnight Run! flow. 2 inch wide flow, 1/4 in deep at 2 ft/s = 0.77917gpm flow. 3 inch wide flow, 1/2 in deep at 2 ft/s = 2.3375 flow. 4 inch wide flow,.75 in deep at 2 ft/s = 4.675gpm flow. 6 inch wide flow, 1.25 in deep at 2 ft/s = 28.05gpm flow. 8 inch wide flow, 4 in deep at 2 ft/s = 49.8667gpm

23. Concurrently Inspect Manholes

24. Report MH 1-11MH 1-1232 MH 1-15 MH 1-344 MH 1-30 MH 1-40330.5 MH 1-30 MH 1-4132.5 MH 1-31 MH 1-3220.35 MH 1-4 MH 1-13530 MH 1-40 upstrea m8150LS FM? MH 1-41 MH 1-424335 MH 1-42 MH 1-4333 MH 1-5 MH 1-66240 MH 1-6 MH 1-75230 MH 161 lateral20.35

25. Map = note only 20% of pipe needs to be investigated – avoided cost was $1.2 M in tving and cleaning in Dania Beach

26. Next Phase  Once Stormwater inflow is out….  Pipelines…

27. Groundwater vs Base+Infiltration

28. Base + Infiltration increases with time

29. Infiltration

32.  A comparison of slopes developed the following findings: 2006 Slope2009 SlopeTotal % Change% Change/Year 0.4147x0.5558x25.4%8.5% In total Dania Beach experienced a 25.4% increase in infiltration between 2006 and 2009. Based on the findings above it is assumed that without any improvements utilities can expect approximately an 8.5% increase in infiltration per year. Infiltration

33.  Work to reduce infiltration within the sewer collection system was initiated in 2012 in Dania Beach.  In order to compare infiltration following pre and post-construction, flow values between 2012 and 2013 were compared. Infiltration Correction

34.  Baseline increase in inflow was calculated to be 14.1% per year.  Baseline increase in infiltration was calculated to be 8.5% per year.  Percent decrease in Inflow was 54.8%  Percent decrease in infiltration was nearly 30% w point repairs  Overall with both efforts, Dania Beach ADF 3.4 to 2.4 MGD from 2005 – 2014 despite adding 0.2 MGD of concentrate to sewer system Results

35.  Based on information provided by the city of Hollywood, Dania Beach currently pays $2.98/1,000 gallons.  Assume 850 Manholes, 60 Miles of pipe Cost Analysis Assume 800 MHInflowInfiltration Sewage Reduced (gallons) 18,348,01172,706,566 Amount Saved($55,044)($216,665) Cost$472,000$772,000 Cost/1000 gallon$22.72$7.64 BUT… Avoided Cost($1,200,000)$0 Cost/1000 gallon($42.68)$7.64

36. Questions