Water Reuse Systems Provide Solutions for Scarcity Concerns Around Globe

As the utilities operations manager for the City of Wichita Falls in north-central Texas, Daniel Nix knows that water is a precious and scarce commodity for the municipality located in an area that averages about 30 inches of rainfall annually. The drought cycle hits the region every 10 to 15 years, and the impact from the latest dry spell was especially tough on the community's water resources.

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"All of that came to a head in this most recent drought when we had two years of back-to-back precipitation below 20 inches annually and one year of record-breaking temperatures where we had 100-degree temperatures for 100 days," Nix said. "We typically only have 26 days over 100 degrees" in a year, he added.

The severe weather pattern that hit in 2011 and continued the following year—when "it was a little bit better" because "we only had 50 days over 100," Nix said—contributed to ongoing challenges for supplying water in the city that has just north of 100,000 residents. "We realized that if we are going to be a viable municipal area for industry and everything, we need to make our resources more sustainable, so we began in the late '90s looking at reuse options," Nix said.

Wichita Falls in July 2014 implemented a direct potable reuse program, which utilized water treated at the local wastewater plant. Instead of releasing the treated liquid back into the environment through reservoirs or rivers, the system returned the treated water back to the city's system for further filtration and treatment using multiple steps, including reverse osmosis and others, to meet strict drinking-water standards.

"We realized the wastewater effluent was basically a nonstop source of water we were just throwing into the Big Wichita River," Nix said. "We realized that resource is one we could capture and keep in our resource loop."

Wichita Falls is not alone as many communities in the U.S. and around the globe are taking extensive steps to conserve water for their cities to use—and reuse.

Saving Water

In the U.S., ongoing drought conditions and other environmental impacts are expected to contribute to a 61 percent increase in wastewater reuse by 2025, according to a report released in July 2015 by Bluefield Research, a firm based in Boston, Massachusetts, that focuses on strategic water analysis. The 61 percent increase is expected to require $11 billion of capital expenditures, with 94 percent of the dollars spent focusing on nine states—mainly Florida and California, the organization stated.

"Potable reuse—treating wastewater to drinking water quality—currently makes up 15 percent of the total capacity but is expected to increase to 19 percent of total water reuse by 2025," according to a statement from Bluefield Research about the study. "The expected jump in potable reuse stems largely from heightening pressure on policymakers and utilities to stay ahead of scaling urban populations, anticipated future droughts and limited water supply alternatives."

Bluefield Research noted that more than 247 reuse projects are in the works in the U.S. Erin Bonney Casey, a research analyst with Bluefield Research, said that more than $1.9 billion of reuse applications have been submitted for approval just in California. "We're seeing a lot of communities addressing this in response to drought. California has really been pushing for reuse because of the current situation they're in. Texas is also supporting reuse," Bonney Casey said.

She pointed to major projects involving water reuse in Texas including the one in Wichita Falls, as well as another program in Big Spring that started a couple years earlier. "Elsewhere in the country, we're definitely seeing an increase in reuse systems," she said, pointing to Texas, Florida and California as the largest areas of activity in the U.S.

Around the world, prime examples of countries leading the charge are outside of North America. "The global leaders of reuse systems would be Singapore and Israel," Bonney Casey said. "Singapore historically has imported a lot of its water from Malaysia. That has some international-relations risks to it, so they're looking for a more localized water supply, and being an island, they're looking at it more aggressively."

Reuse in Singapore

Singapore is a small but crowded island that spans about 278 square miles (roughly 720 square kilometers) and boasts a population of more than 5.5 million people. "In the '60s and '70s, our country was polluted. We had no sewer, and we faced droughts and floods," Maurice Neo, director of the Industry Development Department for Singapore's PUB, or Public Utilities Board, which oversees the country's water infrastructure, said at the 2015 International Desalination Association World Congress gathering. "Now we collect every drop of used water and rainwater."

Image 2. Gayland Bragg with the City of Wichita Falls, Texas, performed work in the municipality's reverse-osmosis plant for the direct potable reuse water program. (Courtesy of City of Wichita Falls, Texas)

Singapore's water system utilizes a multipronged approach that includes water catchment covering two-thirds of the country's land area through the use of 17 reservoirs, according to the organization's annual report for 2014-2015. Plans call for increasing the catchment area by using up to 90 percent of Singapore's land area. "This makes us one of the few countries that harvests urban stormwater on a large scale for water supply," according to the report.

The country also uses a system called NEWater, which purifies "treated used water with advanced membrane technologies—namely, microfiltration, reverse osmosis and ultraviolet disinfection," the report stated. "NEWater allows every drop of water to be used and re-used, creating a multiplier effect. … NEWater is also used to top up our reservoirs and is blended with raw water before undergoing treatment at the waterworks, after which it is supplied to customers for potable use."

Water from the NEWater system "has passed more than 130,000 scientific tests and exceeds the drinking water standards" of the U.S. Environmental Protection Agency and the World Health Organization, Singapore's PUB states in a March 2013 report. NEWater can meet about 30 percent of Singapore's total water demand, but PUB plans to increase it to 55 percent by 2060. Additionally, the country relies heavily on desalination, with two plants that meet up to 25 percent of the country's demand and a third scheduled to start operation in 2017.

"PUB cherishes every drop," Peter Joo Hee Ng, the PUB's chief executive, said at the IDA gathering in San Diego, California. "The future relies on reuse and desalination," he added. "We are always looking for innovations that make things cheaper and cleaner. We put a larger investment into (research and development)."

Toilet to Tap

Part of the challenge with wastewater reuse for potable systems is not just the technology but public buy-in. "A lot of people think of it as toilet water, but really toilet water is only a small portion of the overall sewer usage," said Nix, the utilities operations manager for the City of Wichita Falls. "Toilet facilities are less than 20 percent of that flow," with the vast majority of wastewater coming from showers, sinks, laundry equipment and other household uses, he said.

Image 1. Reverse osmosis is a critical part of the direct potable reuse water program that served the City of Wichita Falls, Texas. (Courtesy of City of Wichita Falls, Texas)

When the city's direct potable reuse system came online in July 2014, residents recognized the importance. "We had huge support from the public," Nix said. "They made the reuse happen. … It was the citizens pulling together that got them through the drought."

In Texas, many government leaders and residents recognize the importance of reuse. "We're very fortunate in Texas that the voters, through the guidance of the Legislature, have provided to our agency $2 billion to help finance water projects in our state water plan," said Dr. Robert Mace, the deputy executive administrator for the Texas Water Development Board. "That $2 billion is a lot of money, but it doesn't go that far in water infrastructure. That money is going to be leveraged into $27 billion of financing power of building water projects and water infrastructure. (Of that amount) 20 percent will go to water conservation and reuse projects."

Texas benefits from about 316,000 acre feet of water from reuse, but the state's water plan is anticipating an extra 1 million acre feet from reuse by 2060, Mace said. The total will represent about 16 percent of municipal use in 2060. "This four- or five-year drought we went through in Texas really expanded communities' awareness of reuse as a potential source of water, so there's been far more interest we've seen in the last few years of reuse than we have ever seen before," he said.

The state's first direct potable reuse system came online in May 2013 in Big Spring. "I like to joke with people that it's a local spring of water, so it's a potential resource that can be used to meet current water supplies without the cost of building big pipelines somewhere to get water," Mace said. "And a lot of times, at least in Texas, generally the community owns that water already so they're not having to buy from somewhere else."

Business Potential

Companies from a variety of industries spanning pump-related businesses, filtration systems and others could benefit from the increase in water reuse projects in the coming years. When asked about observations concerning the importance of water reuse in communities, Dieter Sauer, president of Grundfos Water Utility Inc. based in the Chicago area, said, "It's a topic of conversation that is increasing in frequency every month."

Table 2. Florida and California were leaders in the country in the amount of reused wastewater flows in 2014. (Courtesy of Bluefield Research)

Table 1. The capacity for potable and non-potable water reuse is expected to more than double in the U.S. by 2025. (Courtesy of Bluefield Research)

Calling the reuse of water for municipal purposes "critical," Sauer said the idea of "the complete closed loop, toilet to tap, is maybe a little farther away. … But reuse, when it comes to using it for irrigation and using it for non-potable applications, we are hearing about it more and more." He added, "It seems that more and more in the visits that I make, the wastewater operators are absolutely collaborating with local entities, public and private, to tap into that effluent stream, that water stream, to make good use of it."

Grundfos has invested more than $50 million in municipal water-related activities in the U.S. since 2008, according to the company. "This is a market that we see is viable in the mid to long range. It's going to be a market that is going to invest in infrastructure improvement, and we want to be there to support it when it does," Sauer said. As an example, he pointed to improvements made to the overall efficiency of the water system in Cottonwood, Arizona, which averages about 12 inches of rain annually. "You have a location that is already in a water-challenged area … so water conservation is absolutely critical," he said about the improvements to Cottonwood's utility, which "reduces the impact to that aging infrastructure."

Philip Rolchigo, vice president of technology for Pentair, said water reuse represents an important area of growth for the pumps-related industry. "If you look at our business, our flow and filtration business focuses not only on pumping technology but treatment technology. The trends in water reuse are exciting and growing and are an important component to solving water scarcity issues. We see tremendous growth opportunities in industrial reuse," Rolchigo said.

"These are big trends and really important, I think if not the most important one, one of the most important components to addressing the water scarcity issue," he added. "We think about addressing these global challenges and creating solutions to address these global challenges."

The City of Wichita Falls deactivated its direct potable reuse system in July 2015 after plenty of rain refilled lakes, but the municipality is repurposing the infrastructure for an indirect potable reuse system that will transfer treated water to lakes, Nix said. The new system should be online in 2017 and result in 10 to 16 million gallons of water placed into Lake Arrowhead daily.

Nix recalled a saying by someone involved in what's believed to be the world's first major direct potable reuse system developed in Namibia, Africa. "The Ph.D. that put all of that together has a very famous saying that water should not be judged by its history but by its quality," he said. "You couldn't do something like this 40 or 50 years ago. … We proved that it can be done safely."