Stephen Katz of SUEZ explains the potential of water reuse for future water needs.
by Jennifer King
June 12, 2019

Only 1 percent of the world’s water is usable.

Let that sink in for a moment.

Seventy-one percent of the Earth’s surface is covered by water. But only 1 percent of freshwater is accessible as much of it is trapped in glaciers and snowfields, according to National Geographic.

“Availability is being strained [by] drought, industrial growth, growing agriculture demand, population or urban development growth,” said Stephen Katz, SUEZ’s market development manager, water technologies and solutions. “Our industry is making a shift, from treating wastewater, this problem we had to deal with, to [it] becoming a resource for our sustainability.”

Earlier this year, SUEZ and Wharton IGEL held a water reuse event with business and government leaders and NGOs to discuss water scarcity and a sustainable water future. At the conference, Dave Ross, the U.S. Environmental Protection Agency’s assistant administrator for water, announced the development of a national action plan to promote water reuse that will leverage expertise in industry and government.

According to SUEZ, by 2050, global water needs are expected to increase by 55 percent. But in 2025, more than two-thirds of the world’s population will live in water-stressed regions.

“While conservation and desalination are components in mitigating the crisis, reuse of wastewater from municipal and industrial sources remains the greatest potential source of clean water in the future,” the company’s press release said. “Globally, nearly 80 percent of wastewater is discharged directly into the environment without treatment.

“Wastewater has carbon that can be turned into power, it has water and nutrients you can use to grow stuff,” Katz explained later in a phone interview with Pumps & Systems. “We have this resource that we need to harness.”

He noted that in places like California; Cape Town, South Africa; Singapore; and Australia the availability of freshwater is coming to a head. So, the question is: Where do you go, and what do you do?

“One misconception outside the water world is that there’s new water,” Katz said. “There’s a finite water supply. The concept of water reuse has existed forever—we’re not producing new water; it’s all recycled. It’s just how it gets recycled.”

Katz said the technology today exists to do this.

“We can take any quality of water and make any quality of water,” he explained, noting one part of the equation is the cost to carry out this process with the economics for water recycling making sense now.

Katz offered Southern California as an example—the area does not have a lot of water resources and has to import its water. Currently, the region is pulling water in and pumping it out of the ground at a level that’s not sustainable.

“[Water reuse] can offset water for crops,” he said. “[The process can be] tailored to not pull out all the nutrients, but to pull out pathogens that would make people sick.”

“Then you can go to other levels of treatment for reservoir augmentation or direct potable reuse.”

“The beauty of wastewater and water recycling is it’s local,” Katz pointed out. “Where the water is used, is where the water is needed—you end up with some efficiency there.”

One of the challenging undertakings with water reuse is to ensure the protection of public health.

“The idea here is the appropriate level of treatment; in the future what we’re going to see is ‘fit for purpose’ type of recycling,” Katz said.

Already in California they have a well-established means of determining the appropriate quality for certain uses, he said.

The technologies used for irrigation—landscaping or crops—is a process where biological activity with a membrane barrier allows you to be solids and contaminant free on the permeate side, so you can meet that reuse requirement. Then you have disinfection with something like ultraviolet light to disinfect further. That would provide water for crops or landscaping, Katz said.

There are other technologies that are regularly used for drinking water treatment that can provide the additional barriers to remove any pathogens that would come through.

“Advancements are coming,” Katz said. “Time and effort is being spent today in potable reuse.”

Teams are building flow sheets to show the type of water being used and, depending on where you are and what you’re dealing with, you know where you need to get to. The right pieces get put together to create the “treatment train” needed to meet those objectives.

“You’re starting to see innovation in the development of new treatment trains,” Katz said. “As we couple different technologies together, we’re starting to understand what they can achieve and generate comfort in the different value they enable.”