Wendy Condit

Quality assurance and quality control practices for rehabilitation of sewer and water mains

As part of the US Environmental Protection Agency (EPA)s Aging Water Infrastructure Research Program, several areas of research are being pursued including a review of quality assurance and quality control (QA/QC) practices and acceptance testing during the installation of rehabilitation systems (USEPA 2011). The objectives of this research effort were to collect, analyze and summarize information on the installation and QA/QC practices for the trenchless rehabilitation of sewer and water transmission mains. In addition, consideration was given to practices related to water service lines, sewer service laterals, force mains, siphons, sewer manholes, pumping stations, associated wet wells and other appurtenances. This review was accomplished primarily by conducting interviews directly with rehabilitation technology vendors, design engineers and water and wastewater utilities that have a track record of using trenchless rehabilitation technologies within their network. This paper provides an overview of how QA/QC issues have been handled in North America for trenchless rehabilitation technologies.

Large-Diameter Sewer Rehabilitation Using a Spray-Applied Fiber-Reinforced Geopolymer Mortar

AbstractTo assist utilities in making well-informed maintenance decisions, the EPA has developed an innovative technology demonstration program to evaluate technologies that have the potential to reduce costs and increase the effectiveness of the operation, maintenance, and renewal of aging water distribution and wastewater collection systems. Under this initiative, the performance of a new corrosion-resistant fiber-reinforced geopolymer mortar was evaluated. The fiber-reinforced geopolymer mortar was spray-applied to rehabilitate a preselected 49-m-long, 1,500-mm (160-ft-long, 60-in.) RC pipe (RCP) sewer main in Houston, Texas. Costing approximately

Evaluation of testing methods for tracking CIPP liners’ life-cycle performance

1,300–

Gaps of Decision Support Models for Pipeline Renewal and Recommendations for Improvement

2,000 per linear meter (

Simultaneous removal of perchlorate and arsenate by ion-exchange media modified with nanostructured iron (hydr)oxide.

400–

A pilot study for retrospective evaluation of cured-in-place pipe (CIPP) rehabilitation of municipal gravity sewers

600 per linear foot), a 84-mm-thick (3.3-in.) layer was sprayed uniformly onto the pipe’s interior, surpassing the minimum design thickness value of 48 mm (1.9 in.). The average 28-day compressive strength results of the coating were measured to be approximately 59 MPa (8,635 psi), which is above the manufacturer-stated c...

Innovative rehabilitation technology demonstration and evaluation program

Abstract Despite the significant investments made in the use of cured-in-place pipe (CIPP) rehabilitation technologies, quality assurance (QA) and quality control (QC) practices can vary widely among municipalities, and CIPP liner evaluations are mostly restricted to periodic CCTV inspections. The information in this paper is derived from a multi-year project funded by the U.S. Environmental Protection Agency (US EPA). The study included a first of its kind retrospective evaluation of retrieved CIPP liners that were in service between 5 and 34 years at 18 different locations. This paper focuses on an assessment of the types of testing that were used during a pilot study to perform the CIPP retrospective evaluation. After performing the suite of tests, both visual inspection and flexural testing were found to be the key QA/QC assessment techniques. However, liners’ specific gravity was also found as a useful QA/QC tool and pursuing several other possibilities for non-destructive or minimally-invasive testing for measuring in situ physical properties of liners appeared feasible.

Analysis of Wastewater and Water System Renewal Decision-Making Tools and Approaches

As part of the U.S. Environmental Protection Agency (EPA)s Aging Water Infrastructure Research Program, one key area of research pursued, in collaboration with wastewater and water utilities, was a study of the current approaches available for making rehabilitation versus replacement decisions. The purpose of this study was to: (1) identify the current methodologies and decision support models being used for determining how to rehabilitate or replace underground utilities; (2) identify the critical gaps of these current models through comparison with case history data collected from utilities; and (3) assess the feasibility of substantially improving upon existing approaches. This paper identifies the decision support models and methodologies that have been proposed/used in the US for method selection and discusses the improvements that are required in existing models to make them more directly useful in decision support. A summary from case study visits to utilities in terms of how cities actually make these decisions is also provided. Proposed improvements for the next steps needed to improve current method selection support software are also discussed.