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Separating Inflow Reduction and Infiltration Removal Frederick Bloetscher, Ph. D, PE Florida Atlantic University Separating Inflow Reduction and Infiltration Removal Frederick Bloetscher, Ph. D, PE Florida Atlantic University

Outline Sewer Design Concepts What is Infiltration/Inflow Solutions Effectiveness Outline Sewer Design Concepts What is Infiltration/Inflow Solutions Effectiveness

Design Considerations Gravity sewers flow downhill Designed to flow ½ full Designed for maximum Design Considerations Gravity sewers flow downhill Designed to flow ½ full Designed for maximum hourly flow (MHF) Industrial or domestic Infiltration/Inflow increases the flow volume Location of groundwater table relevant

Sanitary Pipe Materials Small lines: PVC Vitrified clay Asbestos cement Larger lines: Ductile iron Sanitary Pipe Materials Small lines: PVC Vitrified clay Asbestos cement Larger lines: Ductile iron Asbestos cement Concrete

Types of Manholes? Doghouse Precast Drop Brick Types of Manholes? Doghouse Precast Drop Brick

Age and Water = Infiltration and inflow Age and Water = Infiltration and inflow

Sewer Higher than Water Sales? Sewer Higher than Water Sales?

Flows Get Worse with Time Flows Get Worse with Time

Infiltration/Inflow (I/I) Infiltration Groundwater that enters the sewer through defective pipes, joints, connections, & Infiltration/Inflow (I/I) Infiltration Groundwater that enters the sewer through defective pipes, joints, connections, & manholes Inflow Stormwater discharged directly into sewers from roof drains and stormwater runoff Both overloads collection systems & reduces treatment efficiency Function of age I/I = 0. 009 – 0. 9 m 3/d∙mm∙km (typically)

System Hydrograph (INCHES) RAINFALL 16 12 8 4 OCTOBER, 1991 NOVEMBER, 1991 80 60 System Hydrograph (INCHES) RAINFALL 16 12 8 4 OCTOBER, 1991 NOVEMBER, 1991 80 60 (MGD) TOTAL PLANT FLOW 0 40 20 0

Inflow= Rain 4, 000 0. 00 Flow Data vs. Rainfall 3, 500, 000 2. Inflow= Rain 4, 000 0. 00 Flow Data vs. Rainfall 3, 500, 000 2. 00 4. 00 2, 500, 000 Rainfall 6. 00 2, 000 8. 00 1, 500, 000 10. 00 1, 000 Date 1 ec -1 1 D -1 N ov O ct -1 1 11 p. Se A ug -1 1 1 l-1 Ju Ju -1 1 ay M A pr -1 1 -1 ar M Fe n 11 14. 00 1 0 b 11 12. 00 n 11 500, 000 Ja Sewer Flow 3, 000 Flow (Gallons) Rainfall

I/I Allowance (EPA) From Table 3 EPA Infiltration Allowance Range (gpd/inmile) 2, 000 -3, I/I Allowance (EPA) From Table 3 EPA Infiltration Allowance Range (gpd/inmile) 2, 000 -3, 000 Sewage Footage (ft) > 100, 000 3, 000 -5, 000 50, 000 -100, 000 5, 000 -8, 000 1, 000 -50, 000

Sewer Flows v. Rainfall We can see …. . INFLOW!!! Sewer Flows v. Rainfall We can see …. . INFLOW!!!

Inflow =>Sanitary Sewer Overflow STORMWATER CONNECTIONS ALLOW INFLOW SANITARY SEWERS OVERFLOW TO WATERWAYS STREET Inflow =>Sanitary Sewer Overflow STORMWATER CONNECTIONS ALLOW INFLOW SANITARY SEWERS OVERFLOW TO WATERWAYS STREET INLET DOWNSPOUT FOOTING DRAIN SUMP PUMP BASEMENT BACKUP HOUSE SEWER (LATERAL) INFILTRATION WATERWAY SANITARY SEWER STORMWATER SEWER

Sanitary Sewer Overflow Sanitary Sewer Overflow

Inflow Sewer flow peaks during rain events. The size of the storm event matters. Inflow 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 Flow vs. Rainfall 2, 000 1, 800, 000 Flow (Gallons) 1, 600, 000 Inflow Flow vs. Rainfall 2, 000 1, 800, 000 Flow (Gallons) 1, 600, 000 1, 400, 000 1, 200, 000 1, 000 800, 000 600, 000 400, 000 200, 000 0 0. 00 2. 00 4. 00 Rainfall 6. 00 8. 00 10. 00

Inflow Flow vs. Rainfall 2, 000 1, 800, 000 Flow (Gallons) 1, 600, 000 Inflow Flow vs. Rainfall 2, 000 1, 800, 000 Flow (Gallons) 1, 600, 000 1, 400, 000 1, 200, 000 1, 000 800, 000 600, 000 400, 000 200, 000 0 0. 00 2. 00 4. 00 Rainfall 6. 00 8. 00 10. 00

Inflow Flow vs. Rainfall 2, 000 1, 800, 000 1, 600, 000 Flow (Gallons) Inflow Flow vs. Rainfall 2, 000 1, 800, 000 1, 600, 000 Flow (Gallons) 1, 400, 000 INFLOW 1, 200, 000 1, 000 800, 000 600, 000 400, 000 200, 000 0 0. 00 1. 00 2. 00 3. 00 4. 00 5. 00 6. 00 Rainfall 7. 00 8. 00 9. 00 10. 00

Inflow Flow vs. Rainfall 2, 000 1, 800, 000 1, 600, 000 Flow (Gallons) Inflow Flow vs. Rainfall 2, 000 1, 800, 000 1, 600, 000 Flow (Gallons) 1, 400, 000 INFLOW 1, 200, 000 1, 000 800, 000 600, 000 BASEFLOW + INFILTRATION 400, 000 200, 000 0 0. 00 1. 00 2. 00 3. 00 4. 00 5. 00 6. 00 Rainfall 7. 00 8. 00 9. 00 10. 00

Inflow Flow vs. Rainfall 1, 400, 000 1, 200, 000 Flow (Gallons) 1, 000 Inflow Flow vs. Rainfall 1, 400, 000 1, 200, 000 Flow (Gallons) 1, 000 800, 000 600, 000 INFLOW 400, 000 200, 000 0 0. 00 1. 00 2. 00 3. 00 4. 00 5. 00 6. 00 Rainfall 7. 00 8. 00 9. 00 10. 00

Inspect Manholes Inspect Manholes

Protocol – Seal Manhole Frame/Cone Connection Inflow Cover / Frame Inflow Frame / Chimney Protocol – Seal Manhole Frame/Cone Connection Inflow Cover / Frame Inflow Frame / Chimney

Sealing the Manholes Plus Correct Dish!!! Sealing the Manholes Plus Correct Dish!!!

Smoke the System - Finding it? Smoke the System - Finding it?

LDL Plugs for Cleanouts LDL Plugs for Cleanouts

Midnight Run flow. = flow. ft/s = flow. 2 inch wide flow, 1/4 in Midnight Run flow. = flow. ft/s = flow. 2 inch wide flow, 1/4 in deep at 2 ft/s 3 inch wide flow, 1/2 in deep at 2 ft/s 4 inch wide flow, . 75 in deep at 2 ft/s 6 inch wide flow, 1. 25 in deep at 2 8 inch wide flow, 4 in deep at 2 ft/s = 0. 77917 gpm 2. 3375 4. 675 gpm 28. 05 gpm 49. 8667 gpm

Report MH 1 -11 MH 1 -12 3 2 MH 1 -15 MH 1 Report MH 1 -11 MH 1 -12 3 2 MH 1 -15 MH 1 -3 4 4 MH 1 -30 MH 1 -40 3 MH 1 -30 MH 1 -41 3 2. 5 MH 1 -31 MH 1 -32 2 0. 35 MH 1 -4 5 30 MH 1 -40 MH 1 -13 upstrea m MH 1 -41 MH 1 -42 4 MH 1 -42 MH 1 -43 3 MH 1 -5 MH 1 -6 6 2 40 MH 1 -6 MH 1 -7 5 2 30 MH 161 lateral 2 3 8 0. 5 150 LS FM? 3 35 3 0. 35

Map = note only 20% of pipe will be investigated – avoided cost Map = note only 20% of pipe will be investigated – avoided cost

LS 52 – Cooper City LS 52 – Cooper City

LS 53 Cooper City LS 53 Cooper City

LS 54 Cooper City LS 54 Cooper City

Dania – System Dania – System

Savings for Inflow Removal Community Dania Beach (2006 vs. 2009) Cooper City (2011 vs. Savings for Inflow Removal Community Dania Beach (2006 vs. 2009) Cooper City (2011 vs. 2013) % Change (Pre Vs. Post) -31. 9% -62. 8%

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

Groundwater Groundwater

Groundwater vs Base+Infiltration Groundwater vs Base+Infiltration

Base + Infiltration increases with time Base + Infiltration increases with time

Infiltration After removing inflow, the remaining flow is in terms of baseflow + infiltration. Infiltration After removing inflow, the remaining flow is in terms of baseflow + infiltration. Assuming the any increases in baseflow are neglieable, any decreases or increases in flow are related to fluctuations in infiltration. Based on an analysis of baseflow + infiltration vs. groundwater elevations graphs from pre and post construction activities infiltration reduction will be calculated. Separate baseflow + infiltration based on water use , dry days and day of the week

Infiltration Infiltration

Infiltration Baseflow and Infiltration (MGD) vs. Groundwater Levels (ft) Baseflow and Infiltration (MGD) 7. Infiltration Baseflow and Infiltration (MGD) vs. Groundwater Levels (ft) Baseflow and Infiltration (MGD) 7. 00 6. 00 5. 00 4. 00 3. 00 2. 00 1. 00 0. 00 1. 00 2. 00 3. 00 4. 00 5. 00 Groundwater Levels (ft) 6. 00 7. 00

Infiltration Baseflow and Infiltration (MGD) vs. Groundwater Levels (ft) 7. 00 Baseflow and Infiltration Infiltration Baseflow and Infiltration (MGD) vs. Groundwater Levels (ft) 7. 00 Baseflow and Infiltration (MGD) 6. 00 5. 00 4. 00 3. 00 2. 00 1. 00 0. 00 1. 00 2. 00 3. 00 4. 00 Groundwater Levels (ft) 5. 00 6. 00 7. 00

Baseflow and Infiltration (MGD) Infiltration Baseflow + Infiltration (MGD) vs. Groundwater Levels (ft) 7. Baseflow and Infiltration (MGD) Infiltration Baseflow + Infiltration (MGD) vs. Groundwater Levels (ft) 7. 00 6. 00 5. 00 4. 00 2006 2009 3. 00 2. 00 1. 00 0. 00 2. 00 4. 00 6. 00 Groundwater Levels (ft)

Infiltration A comparison of slopes developed the following findings: 2006 Slope 2009 Slope Total Infiltration A comparison of slopes developed the following findings: 2006 Slope 2009 Slope Total % Change/Year 0. 4147 x 0. 5558 x 25. 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 Initial remediation activities of the wastewater collection system were initiated in 2008. Initial Infiltration Initial remediation activities of the wastewater collection system were initiated in 2008. Initial activities included non-construction activities such as smoke testing and rehabilitation activities such as sealing manhole covers and adding manhole dishes to existing manholes. These initial activities were completed to reduce inflow into the system. In order to compare inflow following pre and post construction, flow values between 2006 and 2009 were compared. 2006 flow values represent pre-construction flows and 2009 flow values represent postconstruction flows.

Infiltration Correction Work to reduce infiltration within the sewer collection system was initiated in Infiltration Correction Work to reduce infiltration within the sewer collection system was initiated in 2013. Activities included CCTV analysis of the system and lining pipes in areas where broken or cracked pipes were observed. These initial activities were completed to reduce infiltration into the system. In order to compare infiltration following pre and post-construction, flow values between 2012 and 2013 were compared. 2012 flow values represent pre-construction flows and 2013 flow values represent post-construction flows.

Broken Pipe = Infiltration… Broken Pipe Broken Pipe = Infiltration… Broken Pipe

Leaky Pipe Leaky Pipe

Pipeline Leak Repair Pipeline Leak Repair

Infiltration Calculations A comparison of slopes developed the following findings: 2012 Slope 2013 Slope Infiltration Calculations A comparison of slopes developed the following findings: 2012 Slope 2013 Slope Total % Change/Year 0. 4697 x 0. 4604 x -2. 0% -10. 5% • In total Dania Beach experienced a 2. 0% decrease in infiltration between 2012 and 2013. • Based on the findings above only a small drop in infiltration was experienced. .

RESULTS In order to accurately estimate the percent change we must also take into RESULTS In order to accurately estimate the percent change we must also take into account the amount of inflow and infiltration which would have increased if no work would have been completed. 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 Change Total Net Change Inflow -54. 8% -68. 9% Infiltration -2. 0% -10. 5%

Results A significant decrease in inflow between the pre and postconstruction flows was experienced. Results A significant decrease in inflow between the pre and postconstruction flows was experienced. The construction activities resulted in a total net inflow decrease of 68. 9%. The pre and post construction activities resulted in a significantly less percent decrease in infiltration. Two things to note however, are: The percent decrease in infiltration still accounts for a larger total flow decrease than the inflow decrease because infiltration is such a larger portion of the yearly total flow. The infiltration percent decrease was marginalized due to the fact that baseflow was left in the calculations. Without an adequate way exclude to baseflow, flow measurements were left in baseflow + infiltration. Leaving the baseflow in the analysis does not affect the amount of the flow reduced from the infiltration reduction work but it would decrease the percent change. Even though the percent change is minimalized due to the additional flow within the calculation, it will not affect the cost analysis, which will be based on the amount of flow reduced and not the percent change.

Cost Analysis • The inflow calculations generated previously, based on the rainfall and flow, Cost Analysis • The inflow calculations generated previously, based on the rainfall and flow, were used to calculate the cost savings from the inflow construction activities. • Using the equation created to show the relationship between the 2006 flow and rainfall and the 2009 rainfall values, the amount of inflow that would have been generated if no construction activities were completed was calculate. • 14. 1% was added to the 2006 inflow values based on the 2009 rainfall values to account for the amount of increase in the system which would have occurred if no inflow reduction activities would have occurred.

Cost Analysis • The baseflow + infiltration calculations generated previously, based on the groundwater Cost Analysis • The baseflow + infiltration calculations generated previously, based on the groundwater elevation and flow minus inflow, were used to calculate the cost savings from the infiltration construction activities. • Using the equation created to show the relationship between the 2012 flow minus inflow and groundwater elevation and the 2013 groundwater elevation values, I was able to calculate the amount of infiltration that would have been generated if no construction activities were completed. • 8. 5% was added to the 2012 baseflow + infiltration values based on the 2013 groundwater elevation values to account for the amount of increase in the system which would have occurred if no infiltration reduction activities would have occurred.

Cost Analysis Based on information provided by the city of Hollywood, Dania Beach currently Cost Analysis 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 Assume 800 MH Inflow Infiltration Sewage Reduced (gallons) 18, 348, 011 72, 706, 566 Amount Saved ($55, 044) ($216, 665) Cost $472, 000 $772, 000 Cost/1000 gallon $22. 72 $7. 64 Avoided Cost ($1, 200, 000) $0 Cost/1000 gallon ($42. 68) $7. 64 BUT…

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