SANITARY SEWER EVALUATION OF INFLOW/INFILTRATION REDUCTION TECHNIQUES by Geoffrey Trent VanAllen A Thesis Submitted to the Faculty of The College of Engineering and Computer Science in Partial Fulfillment of the Requirements for the Degree of Master of Science Florida Atlantic University Boca Raton, Florida May 2015 Copyright by Geoffrey VanAllen 2015 ii ACKOWLEDGEMENTS I am using this opportunity to express my gratitude to everyone who supported me throughout the course of this project. I am thankful for their aspiring guidance, invaluably constructive criticism and friendly advice during the project work. I am sincerely grateful to them for sharing their truthful and illuminating views on a number of issues related to the project. iv ABSTRACT Author: Trent VanAllen Title: Sanitary Sewer Evaluation of Inflow/Infiltration Reduction Techniques Institution: Florida Atlantic University Thesis Advisor: Dr. Frederick Bloetscher Degree: Masters of Science Year: 2015 Substantial savings in operations can be achieved by reducing the amount of wastewater that must be pumped and treated. Utilities have long dealt with the infiltration and inflow (I and I) issues in their system by televising their pipes and identifying leak points, but this primarily addresses only the infiltration part of “I and I.” Inflow, which creates hydraulic issues during rain events, leads to sanitary sewer overflows and can subject the utility to fines from regulatory agencies. As a result, dealing with the inflow portion of I and I is needed. The goal of this thesis is to differentiate inflow and infiltration from baseflow and to determine the effectiveness of different methods used to reduce inflow and infiltration in sanitary sewer lines. An analysis was conducted on the benefits and cost effectiveness of different inflow/infiltration approaches (slip-lining sewer lines, stormwater manhole inserts, replacing sewer lines, smoke testing, etc.) and cost savings municipalities can expect to receive from each. v Unlike most other studies, which identify rainfall derived inflow and infiltration (RDII), the goal of this study was to develop a means to separate the flows into inflow, infiltration and baseflow. It was assumed that inflow into sanitary sewer lines is linearly related to rainfall and infiltration is linearly related to groundwater elevation. Based on these assumptions, inflow and infiltration could each be separated out from the wastewater flow, leaving only baseflow. Once the inflow and infiltration have been separated from the flows, pre and post flows could be compared to determine a percent reduction in both to develop a cost analysis. The conclusions developed from this project are directly related to the method for determining the inflow and infiltration reduction, which were related to rainfall and groundwater elevation, respectively. It was shown that inflow is directly related to rainfall, and infiltration (excluding inflow) is directly related to groundwater elevations. The results of the analysis showed that inflow and infiltration correction methods were effective in removing significant amounts of inflow and infiltration from the sanitary sewer system. However, when compared to the cost to complete the construction activities, it was evident that inflow reduction was much more cost effective. vi SANITARY SEWER EVALUATION OF INFLOW/INFILTRATION REDUCTION TECHNIQUES TABLE OF TABLES ........................................................................................................ ix TABLE OF FIGURES ........................................................................................................ x 1.0 INTRODUCTION .................................................................................................... 1 1.1.1 Early History ......................................................................................... 3 1.1.2 Sewer Collection Systems ..................................................................... 4 1.1.3 Pressure Sewer Systems ........................................................................ 5 1.1.4 Understanding the Issues ....................................................................... 5 1.1.5 Terminology .......................................................................................... 8 1.2 Inflow Infiltration Reduction Strategies ......................................................... 11 1.3 Goals and Objectives ...................................................................................... 20 2.0 METHODOLOGY ................................................................................................. 22 3.0 RESULTS ............................................................................................................... 26 3.1 Bay Harbor Islands ......................................................................................... 26 3.2 Dania Beach ................................................................................................... 29 3.3 Cooper City .................................................................................................... 37 3.4 Analysis .......................................................................................................... 44 3.4.1 Inflow .................................................................................................. 44 3.4.2 Infiltration ............................................................................................ 45 3.4.3 Water Wastewater Flow Analysis ....................................................... 46 3.5 Cost Analysis ................................................................................................. 49 vii 3.5.1 Dania Beach ........................................................................................ 50 3.5.2 Cooper City ......................................................................................... 50 3.6 Findings .......................................................................................................... 51 4.0 CONCLUSIONS .................................................................................................... 53 5.0 APPENDICES ........................................................................................................ 55 REFERENCES ............................................................................................................... 134 viii TABLE OF TABLES Table 3-1: Dania Beach Total Net Change ....................................................................... 36 Table 3-2: Cooper City Total Net Change ........................................................................ 43 Table 3-3: Percent Change in Inflow ................................................................................ 44 Table 3-4: Percent Change in Infiltration ........................................................................ 46 Table 3-5: Dania Beach Amount Saved ............................................................................ 50 Table 3-6: Cooper City Amount Saved ............................................................................ 51 ix TABLE OF FIGURES Figure 1-1: Three Components of Wet-Weather Wastewater Flow (EPA, 2007) ............. 9 Figure 1-2: Installation Procedure (courtesy, USSI, Inc.) ................................................ 13 Figure 1-3: Inflow Defender Manhole Rain Dish showing installed dish, and both polycarbonate and polyethylene versions. ........................................................................ 14 Figure 1-4: Smoke Test (courtesy, USSI) ......................................................................... 15 Figure 1-5: LDL Plug Design (courtesy, USSI, Inc.) ....................................................... 16 Figure 1-6: Areas where further infiltration investigation via televising is needed – only 15% of system ................................................................................................................... 18 Figure 3-1: Bay Harbor Islands Flow vs. Rainfall ............................................................ 26 Figure 3-2: Flow vs. Rainfall From 2009 to 2012 ........................................................... 27 Figure 3-3: Bay Harbor Islands Daily Flow vs. Rainfall for 2009 and 2012.................... 28 Figure 3-4: Dania Beach Total Flow vs. Rainfall ............................................................. 29 Figure 3-5: Dania Beach Flow vs. Rainfall for 2006 and 2009 ........................................ 30 Figure 3-6: Dania Beach Groundater Level ...................................................................... 31 Figure 3-7: Dania Beach Baseflow + Infiltration vs. Groundwater Elevations ................ 32 Figure 3-8: Dania Beach Baseflow + Infiltration vs. Groundwater Elevation and Rainfall ........................................................................................................................................... 32 Figure 3-9: Baseflow and Infiltration Vs. Groundwater Levels ....................................... 34 Figure 3-10: Baseflow and Infiltration vs. Groundwater Levels with Trendline ............. 35 x Figure 3-11: Dania Beach Baseflow + Infiltration vs. Groundwater Levels for 2009, 2012 and 2013 ............................................................................................................................ 36 Figure 3-12: Total Flows with Time in Cooper City ........................................................ 38 Figure 3-13: Cooper City Flow vs. Rainfall for 2011 and 2013 ......................................