During the last decade, the U.S. Environmental Protection Agency (EPA) has entered into consent decrees with more than a dozen cities to improve municipal wastewater and stormwater systems to enforce compliance with the Clean Water Act. The focus has been on reducing combined sewer overflows (CSOs) and sanitary sewer overflows (SSOs). According to the EPA, CSOs alone are a major water pollution concern for approximately 772 U.S. cities. As a result of the EPA's legal actions, cities and regional sewer districts serving urban areas have agreed to spend hundreds of millions to billions of dollars over 10 to 25 years to improve wastewater and stormwater management.
Drinking water systems also have significant needs to enhance sources, treatment, storage, and distribution. According to the EPA's most recent Drinking Water Infrastructure Needs Survey and Assessment, based on data collected from utilities in 2007, water systems in the United States need to invest an estimated $334.8 billion between 2007 and 2027 – an amount well beyond any current funding scenario.
Nevertheless, water, wastewater, and stormwater utilities and districts are pushing forward with billions of dollars worth of infrastructure projects, many funded at least in part by utility rate increases. In this first annual Water Projects Pipeline report, CE News highlights a few of the significant stormwater, wastewater, and potable water projects across the United States that are in some stage of planning, design, or early construction.
Wastewater and stormwater projects
Many cities and districts are taking an integrated approach to reducing CSOs and SSOs: improving wastewater treatment plants; developing storage capacity, typically in tunnels; reducing inflow and infiltration (I&I) through sewer rehabilitation and disconnection of private sources of stormwater such as roof downspouts; and retaining and infiltrating stormwater onsite with green infrastructure such as bioretention, permeable pavements, green roofs, green streets, rain barrels or cisterns, and other best management practices.
For example, the Metropolitan St. Louis Sewer District (MSD; www.stlmsd.com) recently agreed to spend $4.7 billion over 23 years to make extensive improvements to its sewer systems and treatment plants. The settlement with EPA requires spending at least $100 million on green infrastructure focused in environmental justice – including low income and minority – communities in St. Louis. Additional projects include construction of three storage tunnels ranging from about two miles to nine miles long; capacity expansion at two wastewater treatment plants (WWTPs); elimination of SSO outfalls; pipe lining; and development of an SSO Master Plan that includes an extensive sewer system evaluation survey, hydraulic modeling, and capacity analysis. The MSD is the nation's fourth largest sewer system, serving a population of approximately 1.4 million. The system covers 525 square miles and includes seven WWTPs, 294 pumping stations, and more than 9,630 miles of sewer lines.
In response to a 2005 federal consent decree, the District of Columbia Water and Sewer Authority (DC Water) embarked on a 20-year, $2.6 billion long-term control plan called the Clean Rivers Project (www.dcwater.com/cleanrivers) to reduce CSOs by a projected 96 percent. DC Water recently awarded a $330.5 million contract for design and construction of the Blue Plains storage and conveyance tunnel. In total, the authority plans to construct a 10-mile main tunnel system to control Anacostia River overflows, plus three miles of branch tunnels to relieve surface flooding and a tunnels dewatering pump station. Hatch Mott MacDonald (HMM) is providing project management, alignment planning, conceptual tunnel and shaft design engineering, risk management, hydraulic design of drop structures, support to DC Water's public outreach program, contract package planning, and contract delivery strategies. A separate three-mile tunnel system and lift station will control overflows to the Potomac River; a mile-long tunnel system will control Piney Branch/Rock Creek overflows.
DC Water also recently broke ground on installing thermal hydrolysis and anaerobic digesters and enhanced nutrient removal (ENR) facilities at the 370 million-gallon-per-day (mgd) Blue Plains Advanced Wastewater Treatment Plant. When the $400 million project is finished in 2014, it will be the largest thermal hydrolysis plant in the world. The process "pressure cooks" the solids left over after wastewater treatment to produce heat and generate 13 MW of electricity – enough to cut the plant's power consumption by a third. The $1 billion ENR project, also slated to be finished in 2014, will reduce the amount of nitrogen in effluent to meet new EPA and Chesapeake Bay Program goals
The Metropolitan Sewer District of Greater Cincinnati is undertaking what it calls the largest public works project in the history of the community.
Project Groundwork (www.projectgroundwork.org) is being conducted in two phases to reduce or eliminate CSOs by constructing larger sewers to transport wastewater to treatment plants or large underground storage tunnels to capture excess wastewater; upgrading existing treatment plants to handle more wastewater or constructing enhanced high-rate treatment facilities to treat flows at the CSO outfall prior to discharge; and managing stormwater by controlling runoff from hillsides, removing streams from combined sewer system intakes, installing stormwater retention basins, and using other controls such as pervious pavement and rainwater harvesting systems.
The first phase of Project Groundwork comprises 38 construction projects and is estimated to cost $1.145 billion and be complete by or before 2018. The second phase, to begin after 2018, is expected to include more than 250 projects and cost about $2.1 billion. Planning and design of these projects may occur prior to 2017, the sewer district said.
The Northeast Ohio Regional Sewer District (NEORSD) entered into a consent decree for a $3 billion, 25-year program – Project Clean Lake (www.neorsd.org/projectcleanlake.php) – to reduce the total volume of raw sewage discharges from 4.5 billion gallons to 494 million gallons annually. The project has three aspects:
- construct seven tunnels, ranging from two to five miles long, as deep as 300 feet, and as large as 24 feet in diameter;
- expand wastewater secondary treatment capacity at two WWTPs; and
- spend at least $42 million by 2019 on green infrastructure projects to store, infiltrate, and evapotranspirate 44 million gallons of stormwater annually before it enters the sewer system.
NEORSD recently began construction on the Euclid Creek Tunnel System (www.neorsd.org/ect), designed by HMM. It will be a 18,050-foot-long, 24-foot-diameter tunnel lined with bolted, gasketed, precast steel-fiber-reinforced concrete segments. Depths range from 190 feet to 220 feet. Additionally, more than 5,000 linear feet of consolidation sewers ranging in diameter from 36 inches to 90 inches will be installed by trenchless and open-cut methods. Completion is expected in 2015.
In August 2011, NEORSD awarded AECOM Technology Corp. a $10 million contract for design and construction management of the Dugway West Interceptor Relief Sewer. This $66 million project includes 10,600 linear feet of main line relief sewer, 4,000 feet of connecting sewers, and modification of more than 40 existing system regulators. Completion is expected in 2016.
Also in August 2011, the city of Indianapolis completed a $1.9 billion transfer of its water and wastewater utilities to Citizens Energy Group, a public charitable trust that operates like a not-for-profit company. The city's water utilities, previously operated by Veolia Water Indianapolis and United Water, are now being operated as Citizens Water. Citizens also will assume responsibility for the city's Long-Term Control Plan mandated under a consent decree. The plan calls for completion of a $3.5 billion CSO project by 2025.
Part of that project is the $300 million Deep Rock Tunnel Connector (www.indy.gov/DeepRockTunnelConnector), which will capture and store CSO from three overflow points, including two of the city's largest; improve management of flows between the city's two treatment plants; and provide future connections to other tunnels. The Deep Rock tunnel, designed by AECOM, consists of approximately 41,600 feet of an 18-foot-diameter tunnel at a depth of 230 feet. A downstream dewatering pump station has a discharge capacity of 90 mgd and an installed capacity of 120 mgd. The project is expected to be completed during 2017.
The $80 million 27th Street Deep Tunnel is a two-mile extension of the Milwaukee Metropolitan Sewerage District's (MMSD; v3.mmsd.com/WastewaterProjects.aspx) existing Deep Tunnel system. The extension will provide an extra 27 million gallons of storage. Upon completion, MMSD's total Deep Tunnel system will store 521 million gallons. The Central Metropolitan Interceptor Sewer (MIS) Improvement Project is a $300 million effort that will add another 50 years of service life to some older MMSD sewers. The project involves rehabilitation – including cured-in-place lining – of about 50 miles of 70- to 115-year-old sewers, which carry about 60 percent of the district's wastewater.
A $31.9 million wastewater relief tunnel in Austin, Texas, is nearing completion. The 3.5-mile Downtown Wastewater Tunnel Project for the Austin Public Works Department (www.ci.austin.tx.us/publicworks/downtowntunnel.htm) will expand wastewater capacity and accommodate continued growth and redevelopment of the downtown and south area of the city. The new wastewater relief tunnel, excavated 50 to 80 feet beneath the surface, makes three crossings of the Lady Bird Lake waterway and varies in diameter from 8 feet and 10 feet to accommodate sewer pipelines of 54 inches to 96 inches in diameter. Work began on the project in January 2010 and is scheduled to be completed in March 2012.
Wastewater projects also are playing a role in enhancing water supplies through water reclamation and recycling. For example, the city of Visalia, Calif. (www.ci.visalia.ca.us/depts/public_works/waste_water.asp), is upgrading its wastewater treatment plant, which will increase the amount of water that can be recycled and help reduce the need for pumping groundwater. The upgraded plant will feature GE's membrane bioreactor (MBR) technology and will be the largest MBR plant in California when it enters service in 2013. Currently, the treated water from the wastewater plant is discharged into a nearby stream. The upgrade of the plant's wastewater treatment processes with the MBR technology will include de-nitrification of the plant's effluent and a substantial improvement in water quality, enabling the city to divert water for local recycling. This will expand both the plant capacity and the city's range of recycled water applications.
Miami-Dade County, Fla., is in the midst of a $600 million High-Level Disinfection Project (www.miamidade.gov/wasd/high_level_disinfection.asp) to produce highly treated wastewater that will then go through the water reclamation process of microfiltration, reverse osmosis, the addition of hydrogen peroxide, and ultraviolet disinfection. This will increase the peak flow capacity of the South District Wastewater Treatment Plant by 27 percent, from 225 mgd to 285 mgd, and allow more wastewater to be pumped to the plant during rain events, reducing the potential of sewer overflows. Reclaimed water will be used to recharge the local groundwater. The project is expected to be completed during the first quarter of 2014.
The San Francisco Public Utilities Commission (SFPUC; www.sfwater.org) recently awarded an AECOM-Parsons joint venture a $150 million contract to provide program management services for SFPUC's $7 billion Wastewater Enterprise Capital Improvement program for multiple projects throughout San Francisco. SFPUC is reviewing latest technologies and cost-effectively implementing best value systems for sustainable infrastructure and improved impact to the environment. When completed, the San Francisco Sewer System Improvement Program, which is part of the Wastewater Enterprise Capital Improvement program, will provide the community with a sewer system and treatment plants incorporating the latest technologies and green designs. The program is slated for completion in 2026.
SFPUC also is undertaking the $4.6 billion Hetch Hetchy Water System Improvement Program (WSIP) to repair, replace, and seismically upgrade the San Francisco Bay area's potable water pipelines, tunnels, reservoirs, pump stations, storage tanks, and dams, including replacement of the Calaveras Dam. WSIP includes 80 projects to be completed by midyear 2016. According to San Francisco Water, Power and Sewer, WSIP is one of the largest water infrastructure programs in the United States and the largest infrastructure program ever undertaken by the city of San Francisco.
On Aug. 16, 2011, a 15-foot-diameter tunnel-boring machine was launched to begin excavation of the $215 million Bay Tunnel under San Francisco Bay. The tunnel, part of the Hetch Hetchy Water System that brings water through gravity-fed pipes from Yosemite National Park to the San Francisco Bay Area, will run 5 miles under the bay, replacing a pipeline built on wooden trestles across the bay during the 1920s and 1930s. Jacobs Associates led the tunnel design team, which included URS, Fugro West, and Telamon Engineering. According to Jacobs, the tunnel will be at depths of 75 to 110 feet in sandy and silty clays under groundwater pressures as great as 3.5 bar. The tunnel will be lined with precast concrete segments and a steel pipe liner.
Another groundbreaking in August began major construction on the Southern Delivery System (www.sdswater.org), a regional water delivery system project that will serve the southern Colorado communities of Colorado Springs, Pueblo West, Fountain, and Security. The project's $880 million first phase includes a connection to the North Outlet Works of Pueblo Dam, 62 miles of underground raw and treated water pipeline, three pump stations, and a 50-mgd water treatment plant, all expected to be completed by 2016. Future phases will include constructing a terminal storage reservoir and exchange reservoir, as well as expanding pumping and water treatment capacity to an ultimate delivery rate of 96 mgd.
Projects highlighted in this article include some of the largest wastewater, stormwater, and drinking water projects currently in planning, design, or construction in the United States, but it is by no means complete. Additionally, many smaller water projects – incorporating innovative design – are providing significant benefits to communities across the country.
Are you involved in design or management of a significant or innovative wastewater, stormwater, or drinking water project? Please send a project summary to Bob Drake, editor, at email@example.com.