By Bently Green, Robert Knecht & Scott Morgan
Memphis is a city of highs and lows, like the sharps and flats in the blues for which the southern U.S. city is famous. Lows like the assassination of Martin Luther King, Jr., and highs like introducing Elvis Presley, Johnny Cash and other music giants through the Sun Records studio. Highs like hosting the world’s largest pork barbecue cooking contest, and lows like having to postpone it this year with the pandemic playing out worldwide.
Lows like having to restore an extensive, largely underground wastewater system that sent wastewater flows where they didn’t belong, and highs like turning that problem into an opportunity to do more than merely stop the overflows.
In September 2012, the City of Memphis negotiated an agreement with U.S. Environmental Protection Agency (EPA), Tennessee Department of Environment and Conservation, and Tennessee Clean Water Network. The resulting consent decree spawned $250 million assessment and rehabilitation program to reduce sanitary sewer overflows (SSOs) from the city’s wastewater collection and transmission system.
The Memphis Public Works Division is responsible for operation and maintenance of the city’s infrastructure, which includes two large wastewater treatment facilities that together serve more than 850,000 customers. It also includes preventive maintenance and emergency repair of more than 3,000 miles of sewers and the operation of 102 sewer lift stations that feed into the wastewater plants. It’s a lot to manage, even before the 10-year Sewer Assessment and Rehabilitation Program (SARP10) launch.
Memphis named Black & Veatch as program manager and construction manager (PMCM) for SARP10. In this role, the company oversees all condition assessment, design engineering, and construction projects associated with the program to help the city navigate the plethora of program elements and manage more than 100 contractors. The PMCM also provides public relations and community outreach, financial review and management, and modeling/analyses. Memphis staff and the PMCM have worked, along with other key participants, as a cohesive program team since the program’s inception in April 2013.
Key program objectives include:
- Assessment of the entire wastewater collection and transmission system, at a rate of about 10 percent per year covering more than 3,000 miles of sewer mains and about 85,000 manholes citywide.
- Rehabilitation of the system, including upgrades to the city’s wastewater treatment facilities.
- SSO elimination or reduction, including basement backups.
- Assignment of engineering field work to local firms to the greatest possible extent.
The Memphis system is getting a much-needed overhaul now, but the asset-management tool developed for SARP10 provides an overview of segment-specific information that will enable city staff to prioritize rehabilitation needs long after the program ends. Photo courtesy of Black & Veatch.
Looking Back and Moving Forward
Memphis built the first separate sanitary sewer system in the United States in 1880 in response to cholera and yellow-fever epidemics. Attributing the spread of disease that decimated its population to poor sanitary condition, Memphis hired engineer George Waring to design a solution. Waring, who was highly regarded for the drainage engineering that created the lakes and ponds of New York City’s Central Park, developed what he believed to be an affordable and effective system. The system collected and transmitted sewage only, separate from surface and stormwater runoff.
The concept was novel. Compared to traditional systems, Waring’s design incorporated smaller pipes and could be cleaned regularly; Waring later approved the addition of larger, gravity sewer pipes and manholes. The scheme worked well, and Waring’s innovation was soon adopted by cities across the U.S.
Over time, the clay and wood pipes deteriorated. Joints broke. Roots, fats, oils, and grease clogged the pipes. Wastewater backed up, and raw sewage sometimes spilled into waterways. What was innovative a century earlier no longer worked for Memphis, and in the fall of 2012 the city finalized the agreement with regulators and enlisted Black & Veatch to oversee the rehabilitation and upgrade of the sprawling system.
Completion of the program will significantly reduce SSOs, infiltration and inflow into the collection system, and environmental and public-health risks. But there is more to the program than meets the eye or lies below. Additional benefits include the development of a holistic asset-management system, economic advancement through local jobs creation and workforce development as a planned element of SARP10, and the promise of greater economic development from the jobs and tax revenues associated with improved infrastructure and water quality.
Building in Asset Management
When SARP10 began, Memphis relied on paper maps to understand the totality of its wastewater system, assets, and connectivity. One of the program team’s first actions was to recruit the University of Memphis to develop a digitized asset inventory of the system based on existing records. Although its accuracy was limited to the accuracy of the original records, the city finally had a digitalized platform to fix pop-up problems.
The customized tool provides a systematic, risk-based process for managing the condition assessment process and prioritizing rehabilitation activity. It features:
- Standardization of field inspection processes, tools, and databases for efficient data collection.
- Creation of a customized GIS tool to manage the pictures, reports, and other data gathered from all system inspections and evaluations.
- Creation of a central database application for storage and analysis of vast amounts of field inspection data.
The asset management tool pulls together all historical information related to specific segments of the sewer system. It includes up-to-date condition assessment and additional data such as pipe size, pipe age, pipe material, population served, historical SSO issues and historical operation/maintenance (O&M) issues. This aggregation of segment-specific information enables the development of probability forecasts to help Memphis prioritize rehabilitation and O&M programs.
Building a Better Workforce and Economic Future
The City of Memphis has made local minority and women’s owned business (MWBE) participation a strategic priority. The team established, and to date has exceeded the MWBE goal of 30 percent for SARP10 – expanding beyond professional services to also include all aspects of the project. In a predominantly African American city of approximately 650,000 residents, more than a third of the work is entrusted to minority- and women-owned businesses.
Early on, Memphis-based Allworld Project Management (Allworld), which specializes in GIS and data management, joined the SARP10 team to provide the bulk of the legwork in quantifying the incoming condition assessment records. As the team started building out the system, its members developed an understanding of the system’s connectivity, characteristics, and dynamics that helped the team more accurately quantify problem areas and focus resources and rehabilitation projects to achieve more value per investment dollar. One result is optimization, with significantly reduced overflows prior to program completion. Another result is significant development of the Memphis minority-owned business.
Allworld has provided approximately 35 percent of the overall program delivery and has played an important role in program success. When SARP10 began, the young company had handful of employees. Seven and a half years into the program, the teaming and mentoring arrangement has helped Allworld grow to include more than 40 technical specialists. Making sure that Allworld employees acquired the skills and experience to assume ever-expanding roles provides added value for Memphis.
SARP10 outreach also has contributed to local economic and workforce development. For example, training and on-boarding provided to candidates from the Benjamin Hooks Job Corps Training Center, and to second-chance candidates from the city’s Workforce Investment Network resulted in approximately 100 people receiving a chance to work on the program, in entry-level and skilled positions.
Offering local contractors and subcontractors free safety training has contributed to an exemplary safety record and enhanced local contractor skills. Photo courtesy of Black & Veatch.
Building in Safety
Another mentoring relationship additionally resulted in an impressive program safety record. In early 2018, the PMCM mentored dozens of local contractors and subcontractors, offering free seminars on hazards mitigation, fall protection, forklift operation, and other important issues. Memphis contractor Wiley Richards and his brother Terrell, who serve as vice presidents in 20-year-old, family-run W&T Construction, thought the training was top-notch and shared what they learned with the minority-owned company’s other employees. The small company both enhanced its safety culture and used its program experience as a springboard into the pipeline condition-assessment market.
The extensive safety training has also helped Memphis maintain an exemplary safety record: more than 1,000,000 work-hours on the program as of June 2020 with no lost-time incidents. It’s kept workers safe and the potentially dangerous undertaking on track.
Hitting More High Notes
SARP10 has already provided a much-sharper picture of the city’s sanitary sewer system and proven how best to eliminate SSOs. Overflows have already plunged by two-thirds of what they previously were.
Using closed-circuit television, sonar, smoke and dye testing, and physical inspections, the program team has collected data on pipelines ranging from 6 to 120 in. in diameter across approximately 60 percent of the city’s 3,000 miles of gravity-sewer lines. The collective team has documented elevations, material construction, and ages of the pipes and inspected the system’s many manholes to pinpoint and prioritize defects for repair. Everything is digitally mapped and instantly accessible with a few clicks of smart phones or tablets. And modeling of the larger-diameter sewers has helped the team identify capacity issues.
The older sewer lines in Memphis were never fully platted and did not have recorded easements. In the process of acquiring permanent sewer easements for these lines and helping the city gain access to the low-lying and wooded areas near streams and creeks where interceptors are buried, the team also helped the city identify and protect environmentally sensitive wetlands.
The program has already produced many ancillary benefits and continues to make tremendous progress in overflow reduction. It is making the environment and quality of life for Memphis residents considerably better.
Bently Green, P.E., is a program manager at Black & Veatch, which works with clients to efficiently and effectively collect, store, move and treat water and wastewater. Green has 30 years of experience primarily in wastewater treatment and infrastructure systems.
Robert Knecht, M.B.A. is the director of public works for the City of Memphis. He is responsible for the city’s third-largest division, which provides many core services including wastewater and stormwater operations, code enforcement, and street maintenance operations.
Scott Morgan, P.E., is the senior environmental administrator for the City of Memphis. He has been with the city since 2006 and specializes in stormwater and sewer construction.
