The WEF Sustainable Utilities Task Force presents a resource for utility managers seeking examples of succesful sustainability practices

Rehabilitating Eight Miles of Large Diameter Aging Infrastructure

Sacramento Area Sewer District
Sacramento, California

The Central Trunk Sewer is an eight mile pipeline that conveys both residential and industrial
sewage for Sacramento County. Constructed in the 1960’s of unlined reinforced concrete, the
pipeline ranges from 33-inches to 60-inches in diameter and is located deep under major roads,
residential backyards, creeks, protected wetlands, and a state highway. Nearly 50 years of
corrosion has severely deteriorated the pipeline and restoring the structural stability of the
pipeline in a cost effective manner with minimal decrease in capacity and distribution to the
community became the primary goals for the Sacramento Area Sewer District (SASD). To meet
these goals SASD and their design consultant West Yost Associates (West Yost) chose cured-inplace
pipe (CIPP) to rehabilitate the entire eight mile pipeline alignment.
Throughout construction several lessons have been learned from this large CIPP project. This
paper will discuss some of the lessons learned as well as considerations for owners and designers
regarding quality control and quality assurance of liner samples, bypass vs. plugging sewer
flows, environmental mitigation monitoring and reporting program, public outreach, air quality
regulations, construction noise mitigation, and debris estimating.


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Posted: May 20th, 2011 | Filed under: >1M, Sanitary Sewer, Stormwater, Waste Water Treatment, Water Treatment | Tags: , , , , , , , , , | No Comments »

Novel Approach for Trunk Sewer Rehabilitation

Orange County Sanitation District (OCSD)
Orange County, California

Wastewater from the coastal areas of the City of Huntington Beach are conveyed to the Orange
County Sanitation District’s Treatment Plant No. 2 through a 1350 mm/1800 mm/2100mm PVC
(Polyvinyl Chloride) lined RCP (Reinforced Concrete Pipe)sewer. The sewer was constructed in
the early 1980′s to service an area that included residential development at the north end that did
not occur due to overwhelming environmental issues. Since then, the sewer has conveyed
substantially lower flows and the portion of the sewer not lined with PVC has been exposed to
corrosive sewer gases and has corroded.
This project included a full evaluation of the condition of the sewer and looked at alternatives for
repair. Ultimately, the course of action included a unique solution that allowed the line to be
rehabilitated with a minimum of impact and disturbance to surface improvements including hotel
resorts and beach activities particularly during the summer.


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Posted: May 20th, 2011 | Filed under: >1M, Sanitary Sewer, Stormwater, Waste Water Treatment, Water Treatment | Tags: , , , , , , , , , | No Comments »