Grantee Research Project Results

Final Report: Effectiveness of Rehabilitation Approaches for I/I Reduction

EPA Grant Number: R825427C005
Subproject: this is subproject number 005 , 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: Effectiveness of Rehabilitation Approaches for I/I Reduction
Investigators: Tittlebaum, Marty
Institution: University of New Orleans
EPA Project Officer:
Project Period: July 1, 1998 through May 1, 2000
RFA: Urban Waste Management & Research Center (1998) RFA Text |  Recipients Lists
Research Category: Targeted Research

Objective:

After nearly two centuries of urban growth and development, public works officials are confronted with the problems of a deteriorating infrastructure and limited maintenance funding. As many wastewater collection systems reach their design life, increasing infiltration and inflow (I/I) has become a serious problem. Portions of a collection system may be so badly deteriorated that repair alternatives become very limited. There is an urgent need to assemble the necessary experience for various repair options, including trenchless technologies, which will minimize system rehabilitation costs.

Over the last ten years there have been significant improvements in technologies and methodologies for sewer rehabilitation. However, the effectiveness of improved technologies and new techniques have not been evaluated. It is therefore difficult for municipalities to properly design a sewer rehabilitation program that will perform as intended. The purpose of this study is to identify and evaluate the effectiveness of new repair technologies from both an engineering and cost perspective. This evaluation will be based upon repairs associated with sewer mains as well as building laterals. Specific variables to be addressed include design, size, age, and construction materials.

The specific objectives of this study are listed as follows:

·Collection of field data pertaining to different approaches and costs of sewer repair and rehabilitation.

·Analysis of the field data to evaluate:

1. Effectiveness and costs of the sewer rehabilitation program based on repairing only the sewer mains.
2. Effectiveness and costs of the program based on repairing sewer mains and the lower portions of building laterals.
3. Effectiveness and costs of the program based on repairing sewer mains and the entire building laterals
4. Impact of other system variables including design, size, age and construction materials.

There are two general circumstances that require sewer line rehabilitation. The first is when sewer lines are experiencing excessive infiltration. The second is when lines are in need of structural repair. Relining methods (cured-in-place [CIPP], fold and formed [F&F], deformed and reformed [D&R], etc.) are marketed heavily to municipalities mainly to address their infiltration problems.

For the most part, these methods have competed directly with open-cut construction for the rehabilitation of sewer lines. The lower social impacts and the decreasing cost of trenchless technology pipeline rehabilitation make these methods more appealing. Unfortunately, the reduced cost of trenchless technology has been the deciding factor in the selection process for many projects, rather than a thorough engineering evaluation of its relative advantages and disadvantages.

Although open-cut construction has many disadvantages when compared to trenchless rehabilitation, it has one big advantage over trenchless methods: It is easy to find a municipality or consultant who is experienced and knowledgeable about open-cut construction techniques. The same cannot be said for the trenchless rehabilitation method, and one would be hard pressed to find expertise from consultants or municipalities.

Over the past 30 years various sewer rehabilitation techniques for the reduction of I/I have been utilized throughout the United States. The actual evaluation of the effectiveness of these techniques from an I/I reduction and cost benefit aspect has been extremely limited.

In order to accomplish the objectives of this proposed study, a total of six specific work tasks have been identified. These tasks are listed below:

Task 1: Survey of Existing Rehabilitation Approaches and Techniques

A survey of the existing rehabilitation approaches and techniques have been performed. Manufacturer information was gathered from available technical literature, data from telephone surveys was documented, and the technical literature was searched. The Office of Wastewater Management, USEPA Washington provided assistance in identifying appropriate consulting firms with experience in various I/I rehabilitation projects, along with municipalities which have performed corrective programs. These sources were utilized to obtain real costs associated with I/I repair, as well as, selection and evaluation procedures used.

Task 2: Investigation of Past Performance History

Various rehabilitation products and techniques were documented. This was accomplished from taking data which was available from the municipal maintenance records, contractors, and evaluation studies. This information, together with the results of Task 1, provided a basis for I/I rehabilitation technique evaluations from both an engineering and cost-benefit viewpoint.

Task 3: Identification of the Rehabilitation Criteria

The actual selection of a rehabilitation technique, the construction techniques utilized, the overall application of the rehabilitation program, etc. all have a significant bearing on the cost and effectiveness of the program. The results of this task was to identify those program design variables, and attempt to establish minimum acceptable values. Variables to be addressed in this task included the following:

·Diameter and length of the pipeline segment to be rehabilitated
·Ovality of the host pipe
·Change of pipe diameter over the length of line being addressed
·Change of pipe material over the length to be rehabilitated
·Number of service connections located in the line segment
·Amount of reduction in diameter acceptable
·Manhole Inspection
·Flow Monitoring
·Smoke Testing
·Flow Isolation
·Dye Water Testing
·Closed Circuit T.V. Inspections

This task established the minimum acceptable. By using documented test results based on the selection criteria identified in this task, a decision can be made to affirm or refute claims made by the manufacturer.

Task 4: Estimating the Overall Impact of the Installation Process on the Surrounding Community and Local Environment

When developing and rehabilitating underground infrastructure one should evaluate the techniques utilized not only in dollars, but also on the total "social impact" of the applied construction methods. Construction techniques such as trenchless technologies were evaluated with respect to their capability to minimize the social costs. Discussions with municipalities with on-going or completed I/I rehabilitation projects, together with USEPA regional office staff, were the primary source of information utilized for the successful completion of this task.

Task 5: Effectiveness and Cost Analysis of the Products

Rehabilitation products were analyzed and compared with respect to their effectiveness in reducing infiltration and/or inflow. An analysis of the various products for rehabilitation were performed to evaluate the cost effectiveness of the products used. This involved life cycle cost analysis (LCA) of different products using different LCA software tools available. The cost data was obtained from the manufacturer of the product and product users.

Task 6: Summary of Effectiveness of Rehabilitation Approaches

The results of Tasks 1 through 5 were compiled and reviewed to finalize product evaluation and rehabilitation techniques with regard to I/I reduction and cost effectiveness. This summary will provide a guide to product availability, rehabilitation techniques, and the costs associated with I/I reduction.

Summary/Accomplishments (Outputs/Outcomes):

The final document was a summary evaluation report which documented the evaluation process, provided recommendations concerning the use of sanitary sewer rehabilitation products, and summarized the findings on the effectiveness and costs of various approaches of sewer rehabilitation. It is intended that this report may serve as a guide by various municipalities to design their I/I and SSO control program.

The survey of existing rehabilitation approaches and techniques has been completed and an extensive history of past performance of engineers/municipalities, along with rehabilitation criteria, has also been documented. The specific rehabilitation approaches and techniques addressed including a detailed descriptions of the findings was included in the final report.

Supplemental Keywords:

sanitary sewer overflows, infiltration, inflow, sewer rehabilitation, trenching techniques, trenchless technologies., Scientific Discipline, Geographic Area, Waste, Ecological Risk Assessment, State, Municipal, Environmental Chemistry, Analytical Chemistry, Ecology and Ecosystems, municipal waste, waste minimization, urban runoff, urban waste, New Orleans (NO), waste management

Relevant Websites:

http://uwmrc.cjb.net Exit

Progress and Final Reports:

Original Abstract

1999

Main 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).
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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
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R825427C010 Beneficial Use Of Urban Runoff For Wetland Enhancement
R825427C011 Urban Storm and Waste Water Outfall Modeling
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R827933C002 Inappropriate Discharge to Stormwater Drainage (Demonstration Project)
R827933C003 Alternate Liner Evaluation Model
R827933C004 LA DNR - DEQ - Regional Waste Management
R827933C005 Landfill Design Specifications
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R827933C014 LaTAP, Louisiana Technical Assistance Program: Pollution Prevention for Small Businesses
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R827933C023 Urban Water Issues: A Video Series
R827933C024 Water Quality Modeling in Urban Storm Water Systems
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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
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