Grantee Research Project Results
2002 Progress Report: Design Criteria for Sanitary Sewer System Rehabilitation
EPA Grant Number: R827933C031Subproject: this is subproject number 031 , established and managed by the Center Director under grant R825427
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: Urban Waste Management and Research Center (University New Orleans)
Center Director: McManis, Kenneth
Title: Design Criteria for Sanitary Sewer System Rehabilitation
Investigators: LaMotta, Enrique , McCorquodale, J. A.
Institution: University of New Orleans
EPA Project Officer: Aja, Hayley
Project Period: December 1, 1999 through June 30, 2004
Project Period Covered by this Report: December 1, 2001 through June 30, 2002
RFA: Urban Waste Management & Research Center (1998) RFA Text | Recipients Lists
Research Category: Targeted Research
Objective:
The general objective of this subproject of the Urban Waste Management and Research Center (UWMRC) is to develop a new design procedure for sanitary sewers to be laid in flat areas. This procedure includes the interaction of biological films and various types of solids, the effect of biological film development on pipe roughness, the effect of bed slope misalignment on solids transport, and the optimization of sewer design for very flat bed slopes. Also, an interactive model will be developed as an aid in the design application of the results of this subprojectstudy.
Progress Summary:
One of the sources of experimental errors in previous experiments carried out as part of this subin this project was the presence of discontinuities in the internal pipe surface as a result ofdue to changes in pipe diameter or pipe thickness, and at the pipe surface sampling sites. To prevent thosethis kinds of errors, new 6-inch and 8-inch transparent PVC pipes were purchased. The 8-inch pipe was installed, and new tests were repeated with and without biological film. By visually observing the water surface, and therefore, by having direct readings of the water depth, determining the position of the hydraulic gradient was accurate, and errors were significantly eliminated.
The following is a summary of the findings:
- The Manning’s roughness coefficient for a clear 8-inch PVC pipe is nearly nearly constant with respect to the depth-to-diameter ratio. Although very few experiments were carried out with a different slope other than 0.1 percent, ( i.e., 0.3 percent), Manning’s η did not vary with the change in slope.
- The value of the Manning’s η derived from the experiments agrees with the value given in literature for the value of Manning’s η for a plastic pipe. The average value was calculated to be 0.011. It should be noted, though, that a lower value of 0.009 was observed for the full-pipe flowing conditions.
- A significant bias error was found in the acoustic flow meter for flows less than 14 L/second, especially at flows less than 6 L/second. The flow meter underestimated the flows; this led to overestimation of the η values in previous experiments. For future reference, at flows between 6 and 14 L/second, the readings of the flow meter should be checked using another method to measure the flow, (i.e., NaCl solution and conductivity meter whichwere used for this research). At flows less than 6 L/second, the flow meter should not be used at all because the underestimation error in the flow meter reading increases as the flow decreases.
- The plastic pipe must be supported rigidly supported to avoid deformation between the support points. The method used to set up the pipe using the wooden beams and the steel plates gave very good results and helped eliminate the errors in the results. It is very important to set up the slope correctly and have a very accurate reading on the invert slope on the pipe. A slight error in setting or measuring the slope can cause a large error in the results.
- When the flow in the pipe is near critical (NF ~ 1), there can be undulations in the water depth. Thus, the flow is not truly uniform.
- When the flow in the pipe was supercritical, (i.e., NF > 1), shock waves were observed inside the pipe.
- A regression analysis was performed to determine the relationship between the dimensionless η and the relative depth and the Reynolds number. The results obtained in this phase of the project do not agree with previous results.
- The value of the self-cleansing velocity was calculated to be 0.37 m/second for the clear 8-inch PVC pipe with a slope of 0.1 percent. T his value is calculated at the 90 percent% transport of sediment. For the 0.3 percent slope, the value was calculated to be 0.34 m/second. However, This value is not reliable, however, because of the near-critical-flow conditions and the surface undulations that were observed.
- The value of the critical shear stress was calculated to be 0.42 N/m2 for the slope of 0.1 percent. For the 0.3 percent slope, the value was calculated to be 0.64 N/m2. This value was calculated at the point where the velocity needed to transport 90 percent% of the sediment was occurring. For the 0.3 percent slope, the value could not be reliably measured because of the surface undulations that were observed and the flow was near critical.
Future Activities:
Similar experiments to the ones described above will be performed with the 8-inch pipe coated with a biological film. Finally, the same experiments, with and without a biological film, will be performed with the 6-inch transparent PVC pipe.
Supplemental Keywords:
sanitary sewers, self-cleansing slopes, roughness coefficients, biological films,, Scientific Discipline, Waste, Water, Ground Water, Ecology, Municipal, Wet Weather Flows, Ecology and Ecosystems, Urban and Regional Planning, sanitary sewer overflows, sanitary sewer system design, runoff, urban runoff, municipal waste, stormwater treatment, stormwater, waste management, water quality, storm drainage, stormwater runoff, storm drainage systems, NPDES, water managementProgress and Final Reports:
Original AbstractMain Center Abstract and Reports:
R825427 Urban Waste Management and Research Center (University New Orleans) Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R825427C001 Comprehensive Evaluation of The Dual Trickling Filter Solids Contact Process
R825427C002 Issues Involving the Vertical Expansion of Landfills
R825427C003 Deep Foundations on Brownfields Sites
R825427C004 Ambient Particulate Concentration Model for Traffic Intersections
R825427C005 Effectiveness of Rehabilitation Approaches for I/I Reduction
R825427C006 Urban Solid Waste Management Videos
R825427C007 UWMRC Community Outreach Multimedia Exhibit
R825427C008 Including New Technology into the Investigation of Inappropriate Pollutant Entries into Storm Drainage Systems - A User's Guide
R825427C009 Investigation of Hydraulic Characteristics and Alternative Model Development of Subsurface Flow Constructed Wetlands
R825427C010 Beneficial Use Of Urban Runoff For Wetland Enhancement
R825427C011 Urban Storm and Waste Water Outfall Modeling
R827933C001 Development of a Model Sediment Control Ordinance for Louisiana
R827933C002 Inappropriate Discharge to Stormwater Drainage (Demonstration Project)
R827933C003 Alternate Liner Evaluation Model
R827933C004 LA DNR - DEQ - Regional Waste Management
R827933C005 Landfill Design Specifications
R827933C006 Geosynthetic Clay Liners as Alternative Barrier Systems
R827933C007 Used Tire Monofill
R827933C008 A Comparison of Upflow Anaerobic Sludge Bed (USAB) and the Anaerobic Biofilm Fluidized Bed Reactor (ABFBR) for the Treatment of Municipal Wastewater
R827933C009 Integrated Environmental Management Plan for Shipbuilding Facilities
R827933C010 Nicaragua
R827933C011 Louisiana Environmental Education and Resource Program
R827933C012 Costa Rica - Costa Rican Initiative
R827933C013 Evaluation of Cr(VI) Exposure Assessment in the Shipbuilding Industry
R827933C014 LaTAP, Louisiana Technical Assistance Program: Pollution Prevention for Small Businesses
R827933C015 Louisiana Environmental Leadership Pollution Prevention Program
R827933C016 Inexpensive Non-Toxic Pigment Substitute for Chromium in Primer for Aluminum Sibstrate
R827933C017 China - Innovative Waste Composting Plan for the City of Benxi, People's Rupublic of China
R827933C018 Institutional Control in Brownfields Redevelopment: A Methodology for Community Participation and Sustainability
R827933C019 Physico-Chemical Assessment for Treatment of Storm Water From Impervious Urban Watersheds Typical of the Gulf Coast
R827933C020 Influence of Cyclic Interfacial Redox Conditions on the Structure and Integrity of Clay Liners for Landfills Subject to Variable High Groundwater Conditions in the Gulf Coast Region
R827933C021 Characterizing Moisture Content Within Landfills
R827933C022 Bioreactor Landfill Moisture Management
R827933C023 Urban Water Issues: A Video Series
R827933C024 Water Quality Modeling in Urban Storm Water Systems
R827933C025 The Development of a Web Based Instruction (WBI) Program for the UWMRC User's Guide (Investigation of Inappropriate Pollutant Entries Into Storm Drainage Systems)
R827933C027 Legal Issues of SSO's: Private Property Sources and Non-NPDES Entities
R827933C028 Brownfields Issues: A Video Series
R827933C029 Facultative Landfill Bioreactors (FLB): A Pilot-Scale Study of Waste Stabilization, Landfill Gas Emissions, Leachate Treatment, and Landfill Geotechnical Properties
R827933C030 Advances in Municipal Wastewater Treatment
R827933C031 Design Criteria for Sanitary Sewer System Rehabilitation
R827933C032 Deep Foundations in Brownfield Areas: Continuing Investigation
R827933C033 Gradation-Based Transport, Kinetics, Coagulation, and Flocculation of Urban Watershed Rainfall-Runoff Particulate Matter
R827933C034 Leaching and Stabilization of Solid-Phase Residuals Separated by Storm Water BMPs Capturing Urban Runoff Impacted by Transportation Activities and Infrastructure
R827933C035 Fate of Pathogens in Storm Water Runoff
R87933C020 Influence of Cyclic Interfacial Redox Conditions on the Structure and Integrity of Clay Liners for Landfills Subject to Variable High Groundwater Conditions in the Gulf Coast Region
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.