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Submission Date: July 21, 2005 Word Count: 2900 Author’s : Rizwan Younis MASc. Candidate Department of Civil Engineering University of Waterloo, Waterloo, ON, N2L 3G1 Email: ryounis@engmail.uwaterloo.ca Tel: (519) 888-4567 x 3875 Fax: (519) 746-6556

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Development of an Underground Wastewater Collection Network Asset Database and Management Framework

ABSTRACT

Communities all around the world dream of living in a safe and healthy environment with stable economy. Civil infrastructure systems such as highways, buildings, water supply and sewerage networks, power generation and distribution systems, and water resources etc. are the backbone of life and all the economic activities in a fluent society. In North America, trillions of dollars have been spent in building the civil infrastructure and now governments face tremendous challenge to sustain it.

Underground infrastructure (water supply and sewerage networks) is often characterized by ‘out of sight, out of mind’ attitude, and is therefore the most neglected one. American Society of Civil Engineering gave a ‘D-’ grade to wastewater systems in its 2005 report card of America’s infrastructure. In Canada, every utility is facing the challenge of assessing the current condition of its wastewater infrastructure so that cost-effective maintenance and rehabilitation strategies can be formulated.

The ultimate goal of this project is to develop a suite of tools which provides the most cost-efficient system of maintenance, repair and rehabilitation of sewer and storm water networks with the aim to guarantee security of sanitary sewage collection and storm water drainage to meet social, health, economic and environmental requirements. This will be done within the context of integrated catchment management and the strategic objective of ensuring security of water resources. INTRODUCTION

Underneath our cities, there lies a huge network of wastewater systems worth billions of dollars. Wastewater infrastructure is approaching the end of its economic life in many communities in Ontario. Defective sewer systems are ‘time bombs’, threatening to contaminate the groundwater and soil, in addition to causing traffic disruptions, loss of property, and in some cases, even loss of life (1).

Increased legislation, environmental consciousness, and tragedies such as Walkerton (Ontario, Canada), where seven people died and more than 2300 got sick after drinking contaminated water in May 2000, have put tremendous pressure on utilities to assess the current health of their buried infrastructure. For example, in Ontario, the proposed Sustainable Water and Sewage Systems Act, 2002, put great emphasis on the principles of full cost accounting, full cost recovery, asset management, public transparency, system sustainability, and financial certainty.

The full cost recovery measures do not address the transitional and possibly longer-term financial difficulties that utilities may experience in meeting increasingly strict regulatory requirements. Utilities are, therefore, under tremendous pressure to optimize and prioritize their maintenance, rehabilitation, and replacement programs so that limited funds can be utilized in the most cost-efficient manner. OBJECTIVES OF THE PROJECT

Some of the basic requirements for an asset management system are that it must maintain an inventory of assets, manage asset condition data, and provide annual and

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long term estimates of costs required to maintain the assets’ condition at or above the target condition level (2). Using the City of Niagara Falls as a beta site, we strive to achieve the following objectives through this project:

1. Development of Asset Management Database

As mentioned earlier, complete inventories and detailed condition assessments of wastewater infrastructure facilities are crucial for estimating costs and for ensuring that rational repair and rehabilitation strategies are employed. This project will develop a comprehensive non-proprietary internet accessible wastewater collection network asset management database using a new Sewer Scanning Evaluation Technology (SSET). Asset database will be developed, tested and evaluated using the City of Niagara Falls’ wastewater system, and this will be the first known complete non-propriety wastewater collection database in North America.

The resulting database will be easily accessible and upgradeable, and will contain key asset attributes such as: environmental data (sewer sediments characteristics, number of overflow discharges etc.); physical asset data (catchment areas, sewer lengths, materials, diameters, age, structural condition, etc.); wastewater storage (storage tanks, volume, etc.); operational data (sewer cleaning, rehabilitation, renovation and replacement, infiltration, blockages, hydraulic capacity, etc.); demography and customer data (resident population connected etc.); quality of service data (flooding, service interruptions, complaints, etc.); economic and financial data (maintenance, operation and rehabilitation costs).

2. Development of Protocols and Algorithms for Quality Control and Quality

Assurance (QC/QA) It is a well known fact that ‘garbage in, garbage out’. Therefore, in order to make

sure that accurate and high quality structural condition assessment data is loaded in the asset database, protocols and algorithms will be developed.

3. Assessment of Sewer Scanning and Evaluation Technology (SSET)

Traditionally, close circuit television (CCTV) technology has been used to inspect sewer pipelines. The analog videos and pictures stored on VHS tapes from CCTV inspections cannot be used for comparison purposes between surveys repeated at different time intervals.

SSET is an innovative digital imaging system for sewer pipeline inspection and evaluation. The SSET probe is capable of continuously recording an electronic “forward looking” image of the pipe at the same time as a full 360-degree scan of the side wall (Figures 1 and 2). Inclination and meander of the pipe are measured at the same time via a built-in inclinometer and on-board gyroscope. The SSET scanning process is performed using a customized mobile field vehicle (MFV). The major components of the SSET field data acquisition (FDA) system include a computer system, an encoder for measuring distances, a pipeline tractor, cable winch system, operator control system, and the SSET probe (Figure 3). During the FDA process, the digital data is stored on a computer hard drive and back-up system and brought back to office for data analysis and interpretation (DAI) (Figure 4). The 360-degree internal pipe surface can be viewed as an unfolded flat digital image (Figure 5). The side scan has a powerful zoom ability that is used to view

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all defects including details such as small roots, cracks, changes in water level, fractures, broken lateral connections, etc. The forward view is invoked at any point along the side scan image to view three-dimensional defects such as protruding laterals and offset joints. With these tools, accurate evaluation of the pipe and documentation of all defects is possible. Reporting requirements are easily fulfilled especially electronic transfer of data to other applications. During the DAI process, features and defects are indicated with a set of drawing tools and automatically recorded. The features and defects are marked and recorded using customizable condition codes. We are employing United Kingdom’s Water Research Centre’s (WRc) Manual of Sewer Condition Classification codes (Version 4) to establish condition of sewer system in the city of Niagara Falls.

As part of this project we will carry out an assessment of sewer scanning and evaluation technology with respect to “value added” over closed circuit television cameras. This evaluation will include survey costs as well as the potential to realize rehabilitation cost savings resulting from higher quality inspection data. It will also follow-up the 2001 Civil Engineering Research Foundation (CERF) report that evaluated an earlier generation of the SSET camera. The evaluation will also investigate how this new inspection technique will impact the role of the municipal engineer with respect to network structural condition evaluation and the potential for the development of asset deterioration curves from sequential SSET surveys.

4. Development of System Performance Indicators Another important aspect of this project is to develop wastewater system performance indicators. The performance indicators are independent of the system. They can be used in three different ways to define rehabilitation policies:

(i) To support immediate decisions about short-term rehabilitation needs, (ii) To understand the current system behaviour, and (iii) To compare alternative design solutions (iv)

5. Development of Dynamic Decision Making Framework The dynamic decision making framework will allow for the development of

rational network maintenance, operation, and rehabilitation policies and priorities. The decision framework will be designed to identify least cost rehabilitation alternatives that provide the required structural, hydraulic and environmental performance requirements within budgeting constraints. This framework will be tested and evaluated using City of Niagara Falls asset database. SUMMARY

At present, a variety of approaches have been applied to estimate the rehabilitation needs of wastewater infrastructure. This project will establish a common systematic intelligent method that will enable accurate and comparable assessments of the specific rehabilitation needs of wastewater infrastructure (Figure 6) (3). In addition, the development of the City of Niagara Falls asset database will provide the foundation for future asset management research projects that are currently not possible due to non-existent or incomplete data sets.

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REFERENCES (1) Wirahadikusumah, R., Dulcy M. Abraham, Tom Iseley, Ravi K. Prasanth.

Assessment of Technologies for Sewer System Rehabilitation. Automation in Construction, Vol. 7, 1998, pp 259-270.

(2) Dalziel, A., Chris Macey. The Benefits of Using Quality Sewer Condition Data in the Asset Management Process. Trenchless Technology, Feb. 2004, pp 36-39.

(3) Lockridge, Robert. The Four C’s of Asset Management, Underground Infrastructure Management, Nov./Dec. 2004, pp 39-41.

(4) Blackhawk Pipeline Assessment Services, Sewer Scanner and Evaluation Technology, CD-ROM.

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LIST OF TABLES AND FIGURES FIGURE 1 SSET Forward Looking View. FIGURE 2 SSET Un-Wrapped Side Scan View. FIGURE 3 SSET Components. FIGURE 4 Software Features. FIGURE 5 Unfolding of Image. FIGURE 6 Different Approaches to Asset Management.

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FIGURE 1 SSET Forward Looking View. (4)

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FIGURE 2 SSET Un-Wrapped Side Scan View. (4)

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FIGURE 3 SSET Components. (4)

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FIGURE 4 Software Features. (4)

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FIGURE 5 Unfolding of Image. (4)

Sewer Scanning and Evaluation Technology

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FIGURE 6 Different Approaches to Asset Management. (3)

Time

Cos

t

Systematic Intelligent

Systematic Naive

Reactive Response