Sanitary Sewer Rehabilitation
G&D has developed an innovative and cost-effective approach to performing sanitary sewer rehabilitation projects that has been very successful at reducing (1) chronic maintenance problems, (2) infiltration and inflow (I/I) peaks and volumes, (3) SSO's, and (4) O&M budgets. G&D works closely to integrate our work processes with those of our clients.
We see our role as primarily to perform SSES, compile and analyze data, provide timely and appropriate technical guidance to the client, prepare complete biddable construction documents, and to manage construction on behalf of the client. Our staff has extensive experience in the analysis of SSES data. Successful rehabilitation contracts require quick turnaround of the SSES data. G&D owns and uses WinCan© with the PACP module to collect, store and analyze CCTV data amongst other tools.
- City of Charlotte Central Business District Area 4 (CBD-4) Sanitary Sewer Rehabilitation Project
This $3.1 million project involved the rehabilitation of 50,000 linear feet of sanitary sewer ranging from 8 to 18 inches in diameter. The project was a "find-it-and-fix-it" contract, in which the contractor cleaned and performed CCTV inspection of the sewer mains, and submitted the video to G&D for review and direction regarding the required rehabilitation.
Most of the pipe was lined with CIPP, and many segments required point repairs in downtown streets and sidewalks with numerous buried utilities. The project also included 250 manholes, most of which were lined with cementitous liner, and required installation of new frames and covers. Most of this work was done at night to avoid disruptions of traffic and business, but the project also included work around residences where the City noise ordinance required the work to be performed in the day.
G&D's responsibilities included observation of sewer main lining and manhole lining; witnessing vacuum tests of manholes, performing manhole inspections; mapping manholes using a Trimble Geo XT GPS receiver and transferring data to CMU mapping specialists. G&D was also part of a 24-hour response team that was needed to be on site in the event of overflows or service disruptions that can result as part of the liner installation process.
- Winston-Salem Wastewater Collection System Improvements 2010
G&D assisted the City of Winston-Salem/Forsyth County Public Utilities (Utility) in rehabilitating portions of its collection system that have experienced sanitary sewer overflows (SSO's) or other serious operation and maintenance (O&M) issues.
The locations of the five discrete areas are distributed throughout the City. G&D has been tasked by the Utility to develop a cost effective sanitary sewer rehabilitation program. G&D's scope of work was divided into three separate phases: (1) Analysis, (2) Design, and (3) Construction. G&D has now completed Phases 1 and 2, and Phase 3 should begin in early August 2010. The project recently bid at a total construction cost of $902,952.
Under Phase 1 of the project, G&D inspected and evaluated the existing sanitary sewer system in the project areas. The inspection and evaluations provided the basis for design for the renovation/replacement of identified segments of the Utility's sanitary sewer conveyance system. Inspection work included the cleaning and closed-circuit television (CCTV) inspection of all pipes, manhole inspections, and assessment of existing facility conditions using accepted evaluation standards.
Development of the proposed sanitary sewer rehabilitation program for the existing sanitary sewer system included evaluation of site alternatives, preliminary design, and estimations of construction costs. G&D designed a suite of improvements that includes CIPP, pipe bursting, sewer realignment and manhole replacement, cementitious manhole lining, service lateral replacement, and other miscellaneous improvements.
- Ardmore Branch Sanitary Sewer Rehabilitation, Winston Salem NC
G&D provided inspection services for the Ardmore Branch Outfall Sewer Rehabilitation Project for Winston/Forsyth Utilities. This project involved pipe bursting over 5,000 LF of 15- and 18-inch sewer, and open cut replacement of an additional 4,000LF of 18- and 24-inch sewer.
Work also included manhole rehabilitation and replacement of 13 aerial stream crossings. G&D was also responsible for the design of three of the replacement aerial sanitary sewer stream crossings: two 8-inch diameter and one 15-inch diameter that were up-sized to a 16-inch. Construction of the aerial crossings is complete.
- Suttle Street Sanitary Sewer Rehabilitation
G&D was contracted by the City of Shelby to assist staff in the evaluation of areas identified as having chronic maintenance problems or known sources of infiltration and inflow (I/I). It became evident in performing inspections that most or all the annual budget of $500,000 could be spent on work needed in the Suttle Street area alone.
Following the performance of the SSES and associated analysis, G&D performed the design and prepared the contract documents for the rehabilitation of 5,000 feet of sewer and 31 manholes. This project was a mix of CIPP and "dig-and-replace", and included rerouting of sewer to avoid buildings, demolition of decrepit housing, and the reroute of an aerial stream crossing.
- Chestnut Neighborhood Sanitary Sewer Rehabilitation
The City of Shelby has adopted a citywide infrastructure improvement program that seeks to improve existing conditions of economically challenged areas. These services include utility infrastructure repairs among others. The Chestnut neighborhood was selected to be part of this infrastructure improvement program.
Based on gathered CCTV data, GIS maps, and field measurements, the proposed project area is estimated to consist of approximately 12,000 feet of gravity sewer street mains and an outfall trunk sewer with 67 manholes. G&D performed various SSES activities and generated a technical memorandum recommending a comprehensive rehabilitation through CIPP. G&D assisted in the preparation of a grant application on behalf of Shelby to fund the construction of the (approximately) $700,000 project. Construction of this project is complete and included a new jack-and-bored cassing of an NCDOT roadway, CIPP, and manhole rehabilitation.
- Emergency Repair of Aerial Stream Crossing for Kannapolis
In September 2006, G&D provided emergency design services for repair of a failed 18-inch aerial sewer stream crossing. The $75,000 repair was completed within 2 weeks, including design.
- Coddle Creek Trunk Sewer Corrosion Remediation (WSACC)
A drop manhole along the Coddle Creek Sewer Outfall is significantly corroded such that the ground surface around the manhole has subsided, indicating that a void is present in the drop connection. Further, odor complaints have been received by the Water and Sewer Authority of Cabarrus County (WSACC) from adjacent property owners due to the release of hydrogen sulfide gas.
G&D has performed various inspections, reviewed CCTV tape, and developed a suite of alternatives for the Authority to consider to address the problem, including (1) sewer realignment to eliminate the drop manhole, (2) manhole replacement with bypass to eliminate the drop, (3) manhole lining with a variety of materials including Hobas, (4) bioxide addition upstream, or (5) routing air to an existing scrubber located downstream.
G&D directed further inspections to determine the structural condition of the existing pipes and manholes to support a decision related to the urgency of the recommended improvements. G&D subsequently designed a replacement drop manhole, manhole lining, and CIPP lining repair of the trunk line that is currently under construction.