Combatting environmental threats, improving water quality and public health, and providing economic benefits through One Water strategies
Submitted by Tetra Tech
In an era of mounting global water stress and increasing pressures on the planet’s water resources, sustainable solutions are urgently needed to ensure that our water supplies are as resilient as possible. The World Health Organization estimates that half of the world’s population will live in water-stressed areas as soon as 2025. As populations surge and the demand for water intensifies, the challenge to provide reliable, clean water supplies grows increasingly more difficult. Fifty percent of the world’s population relies on groundwater as their source of drinking water, and critical underground aquifers are being depleted at an alarming rate.
While the challenges may seem daunting, Tetra Tech has never been more prepared to face them. We have the cutting-edge tools, advanced data analytics, and scientific knowledge necessary to develop smarter and more efficient solutions than ever before.
Tetra Tech’s foundational work in water is the underpinning of our industry-leading, integrated water management practice. Our legacy of solving complex water challenges started in 1966, when Tetra Tech’s four founders—each representing a distinct scientific discipline—used their academic passion to tackle complex projects and deliver innovative solutions for clients.
Fast-forward to today, and Tetra Tech is at the forefront of applying technology and analytics to the development of resilient, sustainable solutions. In 2019 the industry trade magazine, Engineering News-Record (ENR), ranked Tetra Tech #1 in Water for the 16th consecutive year in its Top 500 Design Firms issue. Our institutional knowledge in water—gained over decades of experience—has enabled us to take the lead in addressing the imminent water challenges we all now face.
The value of a One Water approach
Tetra Tech is actively engaged in Leading with Science® to develop global One Water solutions that address complex water issues using a holistic, integrated approach. A One Water approach recognizes the water cycle as an integrated system and embraces the view that all water holds value. One Water shifts from a linear model of water management to a circular strategy, emphasizing recovery, recycling, and reuse instead of discharge. Wastewater, long seen as merely a byproduct of the treatment process, is now considered a valuable resource that can be recycled and used for irrigation, industrial operations, and other purposes.
Tetra Tech carefully designs solutions that embrace this approach to achieve multiple objectives—including more reliable water supplies, cleaner water sources, and greater long-term water security.
The following examples highlight specific challenges in the water sector and the solutions Tetra Tech has delivered to ensure safe, abundant water supplies for communities around the world.
Enhanced groundwater reliability in Southern California
Groundwater resources from California’s Central Basin are a vital component in Los Angeles County’s mission of supplying the drinking water needs of approximately 4 million people. To sustain the Central Basin water supplies, groundwater recharge is critical. Local agencies traditionally have replenished the basin’s aquifers using a combination of stormwater, imported water, and recycled water, but long-term drought, increased demand, and environmental restrictions have made importing water an unreliable option.
To replace the imported water component and increase the availability of high-quality water to recharge the Central Basin, the Water Replenishment District of Southern California (WRD) selected the design-build team of JF Shea and Tetra Tech to complete the Albert Robles Center for Recycling and Environmental Learning (ARC) and the Advanced Water Treatment Facility (AWTF).
“By putting this project online, WRD creates a local, sustainable supply of water for replenishing the groundwater system,” said Tetra Tech Senior Vice President Steve Tedesco. “WRD also becomes independent from buying imported water from Northern California or the Colorado River. The cost of imported water has risen tremendously over the last 10 years and will continue to get more expensive with increasing scarcity. The ARC project mitigates that risk.”
The ARC AWTF treats tertiary effluent from the San Jose Creek Water Reclamation Plant (SJCWRP) to near-distilled water quality using high-end technology solutions, including ultrafiltration, reverse osmosis, and ultraviolet radiation disinfection with an advanced oxidation process. The treated, ultraclean AWTF effluent is then blended with tertiary effluent from SJCWRP and conveyed to the Montebello Forebay Spreading Grounds to percolate into the soil and replenish groundwater resources.
A water lifecycle approach in Mongolia
In addition to periods of drought and global population growth, deteriorating water quality conditions also can limit available drinking water supplies. Following years of rapid population growth, Mongolia’s capital city of Ulaanbaatar faces significant water supply and water quality challenges. Mounting water demand is intersecting with declining regional water availability, driving an urgent need to develop new water supplies.
Ulaanbaatar’s sole source of drinking water is the groundwater aquifers along the upper reaches of the Tuul River. Studies indicate that any additional extraction from those upstream aquifers will diminish river flow and cause portions of the river—which flows through the city—to run dry. Consequently, new water supply development must target groundwater aquifers downstream from the city. That strategy is complicated by the fact that poorly treated discharge from Ulaanbaatar’s outdated central wastewater treatment plant has contaminated the Tuul River, potentially introducing harmful contaminants into the downstream aquifers.
Tetra Tech is working with the Millennium Challenge Corporation and the government of Mongolia to create a more sustainable, long-term water and wastewater system.
Tetra Tech is working with the Millennium Challenge Corporation and the government of Mongolia to create a more sustainable, long-term water and wastewater system. Key components of the water supply project include new aquifer development in downstream wells, a state-of-the-art plant to purify drinking water, and a water recycling facility to treat wastewater effluent for reuse.
“By addressing source water, reclaimed water, and wastewater, the program touches on the whole water life cycle in Ulaanbaatar,” said Edward Gardiner, Tetra Tech vice president and project manager. The new water recycling facility will treat wastewater effluent for reuse in the cooling towers of two of the city’s combined heat and power plants, supplying up to 70 percent of their water needs and conserving groundwater resources. A proposed central wastewater treatment plant in Ulaanbaatar will dramatically improve the quality of effluent discharged into the Tuul River, addressing the source of pollution and helping to enhance water quality in the new downstream well field.
A diversification strategy in drought-prone San Antonio
In arid regions, diversified water supplies are essential to making communities self-reliant and able to manage periods of water stress. In San Antonio, Texas, diversification is a key approach the San Antonio Water System (SAWS) uses to ensure future water supply reliability for the city—one of the largest and fastest growing in the nation.
Tetra Tech has provided 20 years of continuous support to SAWS to help diversify its water supply sources. Tetra Tech was the design engineer for SAWS's brackish groundwater desalination plant (H2Oaks), which uses reverse-osmosis technology to treat brackish groundwater extracted from deep in the Wilcox Aquifer to produce potable water. Using an innovative design, our engineers were able to improve efficiency and extract an additional 1 million gallons of fresh water from the system each day.
The latest component in the SAWS diversification strategy is the Central Water Integration Pipeline (CWIP), a water supply project that will integrate treated groundwater delivered from 142 miles away to help supplement SAWS's water supplies. Tetra Tech is the lead designer for the CWIP project, providing design, bid, and construction administration services.
“The project includes approximately four miles of new pipeline with two miles of tunneling through urban areas, improvements to three existing pump stations, two new water storage tanks, and a 48-million-gallon-per-day water treatment plant at the Agua Vista site in San Antonio that will treat the water to match the existing water quality in the SAWS distribution system,” said Tetra Tech Project Manager Leslie Turner.
When CWIP is complete, the latest addition to San Antonio’s diversified water strategy will provide roughly 20 percent of the City’s annual water needs.
An integrated water and sewer approach in Miami-Dade County
The Miami-Dade Water and Sewer Department (MDWASD) is the largest water and sewer utility in the southeastern United States and serves nearly 2.3 million residents, including thousands of daily visitors. To continue to fulfill its vision of continuous delivery of high-quality drinking water and wastewater services in compliance with all regulatory requirements, MDWASD launched an integrated multiyear capital improvement program (CIP) that incorporates asset management, system growth, climate change resiliency, and other considerations.
Tetra Tech provided engineering services for the CIP, focusing on integrated master planning for water, wastewater, groundwater, and reclaimed water. Tetra Tech’s planning work considered the interconnectedness of these water resources—maximizing the value of each component of the water cycle.
“Overall, our cumulative efforts embraced sustainable solutions to achieve efficient long-term water supply management,” said Ken Caban, Tetra Tech vice president and southeast Florida regional manager.
One aspect involved evaluating the technical and economic viability of reusing reclaimed water for different purposes. Based on a mandate that MDWASD eliminate ocean outfall discharges of wastewater, Tetra Tech conducted a reuse feasibility study to determine the cost and feasibility of various uses, which included golf course irrigation, industrial reuse, and recharging wetlands in Everglades National Park.
“Ultimately, we determined the best opportunity was to reuse that water for industrial cooling at a Florida Power and Light facility,” said Tetra Tech Senior Project Manager Diana Santander. “Doing so will help reduce groundwater withdrawals, conserving those resources for better and more efficient uses.”
Tetra Tech also focused on optimizing groundwater extractions for more efficient use and developed a facilities master plan for water treatment. Ken said, “As an alternative to building costly new water treatment plants, we identified investments in asset management and rehabilitating existing plants to allow reliable operation for the next 20 to 50 years.”
High-tech solutions to reducing water loss in Jordan
While tremendous technological advancements have been made in replenishing groundwater supplies through reuse and reinjection, the World Bank estimates that up to 35 percent of potable water supplies globally are lost through leaks in distribution systems. Jordan is one of the most water-stressed countries in the world, with diminishing freshwater supplies and rising water demand. Unsustainable extraction rates are exhausting groundwater resources, and roughly half of the water produced by Jordan’s utilities is unaccounted for as a result of leakage, theft, and other management challenges. Increasing energy prices have led to higher water production costs, and an influx of more than one million refugees from regional conflicts has heightened the need for effective water sector management and governance.
The Water Management Initiative (WMI), funded by the U.S. Agency for International Development (USAID), supports the government of Jordan in addressing these imminent water challenges and avoiding a looming water crisis. USAID engaged Tetra Tech to implement WMI, helping Jordan improve its water sector management and enhance the sustainability of its water supply systems.
Tetra Tech’s primary focus is working with Jordan’s water utilities and other water management entities to upgrade their measurement and management systems and help them function more efficiently. David Favazza, Tetra Tech ARD senior associate and home office project manager for the Jordan WMI, said, “With so much water going missing in their distribution systems, a big part of our effort is reducing that loss.”
Specifically, Tetra Tech is supporting the Jordan Valley Authority in developing an effective water loss management strategy for the King Abdullah Canal, the country’s most important water conveyance system for supplying irrigation and municipal needs. Tetra Tech is also working with the Ministry of Water and Irrigation to identify unauthorized groundwater withdrawals in the Jordan highlands, where significant groundwater depletion is occurring.
“The solutions leverage advanced technologies such as satellite-based remote sensing to identify illegal groundwater withdrawals in the highlands and Doppler technology to accurately measure flows and pinpoint leaks and theft in the King Abdullah Canal,” David said. “But to really be lasting, any solutions need to be driven by broader systems that incentivize improved performance and ensure transparency and accountability. That’s where the biggest gains will happen in the long term. So, in addition to introducing new technologies, we are helping Jordan improve water governance and management systems.”
Data analytics optimize Anchorage’s water and wastewater utility
With the advances in technology, utilities can literally collect trillions of data points each year. More data is not always better data, as the Anchorage Water and Wastewater Utility (AWWU) discovered. AWWU engaged Tetra Tech to help improve the reliability and efficiency of the utility’s treatment processes, water distribution, and wastewater collection.
Robert Ivanovic, Tetra Tech control systems expert, said, “As more data become available, data quality is increasingly important. One of the issues in Anchorage was that their system was collecting too much information. They were so inundated with data, that the information had become useless. So, a component of the project was to focus only on relevant data.”
AWWU owns and operates three water treatment facilities, three wastewater treatment plants, and about 1,600 miles of pipeline and associated facilities. The improvements were part of AWWU’s vision to implement industry best practices and reduce the overall cost of ownership without jeopardizing operational capabilities.
The Tetra Tech team approached the project by performing a full condition assessment of the SCADA system and its users. “SCADA stands for Supervisory Control and Data Acquisition, which essentially monitors the daily operations of the treatment plant,” said Rob. “We analyzed how AWWU staff conducts day-to-day operations and maintains the system, and then we looked at the technology itself to see how it was implemented and how it is used.”
Resilience issues were discovered within the organizational framework of AWWU’s staffing structure. “One person might hold necessary information, creating single points of failure in the system,” Rob said. “Our plan identified this risk and provided an alternative that would reorganize this structure, prioritizing operational improvements and situational awareness.”
Tetra Tech’s strategy was to map the SCADA functionality into the future focused on critical data, maintenance and operations, and a robust network design with the ability to feasibly implement future technology add-ons.
Improved data analytics have allowed AWWU to view its systemwide treatment, water quality, distribution, energy consumption, and chemical usage more holistically and make better management decisions
Improved data analytics have allowed AWWU to view their systemwide treatment, water quality, distribution, energy consumption, and chemical usage more holistically and make better management decisions, according to Rob. “AWWU can be more proactive and use predictive maintenance to pinpoint leaks or identify water quality issues in the system. They can also look at historical data and analyze trends to know how to be more efficient as a utility.”
Real-time data equals real-time savings in Louisville
More than 800 communities across the United States have combined sewer systems designed to transport both sanitary waste and stormwater through the same pipes to the wastewater treatment plant. That means a rain event could overwhelm the wastewater collection and treatment capacities and the untreated wastewater would flow directly into waterways, creating potential health risks. The capital expenditures of conventional solutions to capture the additional volume could become cost prohibitive for a public utility.
Similar to the way traffic lights on surface streets route vehicles to the least congested areas, Csoft works with sensors, weather forecasts, and monitoring data to move the wastewater through networks that have additional capacity.
The Louisville Metropolitan Sewer District (MSD) in Kentucky faced similar challenges and hired Tetra Tech (QIB) to explore alternative solutions. Tetra Tech’s team of modelers, mathematicians, and water engineers had developed Csoft®, a propietary model-based predictive control tool that minimizes sewer overflows and flooding risks. Similar to the way traffic lights on surface streets route vehicles to the least congested areas, Csoft works with sensors, weather forecasts, and monitoring data to move the wastewater through networks that have additional capacity.
“The biggest challenge we faced with Csoft,” said Martin Pleau, Tetra Tech Csoft design engineer, “was to acquire and validate the data, simulate the model in real time, solve the optimization problem, and apply the optimal control set points at the local facilities—all in less than 5 minutes.”
Tetra Tech’s initial real-time control (RTC) feasibility studies for MSD using Csoft showed significant reductions in the number of combined sewer overflows at a relatively low cost by maximizing the storage and conveyance capacities within the existing system.
“RTC is now an integral part of MSD’s plan to continue to reduce overflows,” said Angela Akridge, chief engineer at MSD. “The optimization provided by Csoft allows us to be more resilient, and the more than $200 million we’ve not spent on traditional overflow storage at these facilities has allowed us to invest that money into other critical infrastructure, providing safe, clean waterways for our community.”
In April 2019, Tetra Tech and MSD won the prestigious Franz Edelman Award, which recognizes the improvements that operational research and analytics are making in the way people live and work around the globe. The Csoft solution has been in successful operation in Louisville since 2006 and has withstood the test of time and changing climate. It also has been successfully implemented in other locations within the United States, in addition to Canada and France.
Smarter solutions for a water-secure future
The water challenges are significant, but Tetra Tech believes that in the face of great challenges come tremendous opportunities. Each year, more examples of One Water solutions are put into practice as communities increasingly recognize the benefit of managing water in more integrated and sustainable ways. By embracing intelligent water resources planning that considers all phases of the water cycle, we can build more resilient water systems and help ensure a more stable water future.
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