The irony of wastewater, the waste product of the use of water, is that it is already in the location where fresh water is needed. It is time the linear use of our most precious resource gave way to a sustainable continuum, HELEN COMPSON reports.
It is a contradiction that cannot be allowed to continue.
As a report produced by the Initiative for Global Environmental Leadership, founded by Wharton University of Pennsylvania, lays bare, today more than 40% of the world’s population is affected by water scarcity with 17 countries under “extremely high” water stress, using almost all of their resources.
According to United Nations figures, “Over 1.7 billion people are currently living in river basins where water use exceeds recharge.”
And the problem is only going to get worse. It is predicted the global population will grow by another two billion to 9.7bn people by 2050.
More than half of them (52%) will be living in regions experiencing water scarcity.
As Stephen Katz, market development manager for water reuse with global giant SUEZ – Water Technologies & Solutions, makes clear, recovering wastewater so that it can be reused – and yes, that includes being used as drinking water too – will be key to eking out this world’s finite supply.
“Bringing back wastewater as drinking water is an emerging trend in the market,” he said.
“When you drill the facts down, the concept of our water usage has been linear – extract, treat, use, discharge.
“However, now we are moving into this world of circularity in which water is reclaimed and reused, and I’m looking at the future when I say a significant amount of the work in the water industry lies in this area.”
Some were put off by the idea of consuming what had once been wastewater, he acknowledged, but to the naysayers he points out that we are still reliant now on the water that was around when the dinosaurs were walking this planet.
“The water that exists today is the water that existed millions of years ago,” he said. “People should be aware of the fact that rain isn’t magic new water sent from the universe.
“It’s all part of the water cycle taught to us in school using the image of a lake and a mountain and evaporation and big fluffy clouds. It is not an imaginary cycle … the only difference is that we have just dropped communities and industry in the middle that weren’t drawn in this natural cycle “
Reclaiming wastewater therefore could be and should be a natural part of humankind’s water supply, a sustainable element of a sustainable continuum.
In the 21st century, there were four engines driving change in the water industry – climate change, the increasing demographic challenge, a digital revolution, and public expectation/activism.
And SUEZ, which specialises in the innovative technology, predictive analytics and solutions needed in both the water and wastewater industries, is well-placed to respond.
Offering a comprehensive range of chemical and equipment solutions and services, the company has 450,000 business and industrial customers and 90,000 staff globally.
It also has an annual research and development expenditure currently running at E120m.
The water industry is in a state of transition generally, there’s no doubt about that, he said, and water companies individually had three key transitional factors to contend with.
One, wastewater is becoming a feedstock. “It is a fuel in that it has organic matter that can be converted to gas, nutrients that can be recycled for fertiliser and water that is water. This is a key focus for our own water teams today.”
Two, the lack of availability of fresh water, particularly in relation to the growing size of the population a company might be catering for while dealing with a diminishing source of supply.
Three, the size and scale of the utilities – is there actually the space for a company to grow its treatment footprint in tandem with the growing call on its resources, while balancing the demand for space in the community.
Stephen said: “What does that all mean in terms of technology and municipalities and the industry as a whole?
“Well, that is our first question, always, at SUEZ. We are looking to solve these problems to create a more sustainable water supply for our clients and their customers in municipalities and industry.”
Depending on the water source, the desired outcome and the quality of water that is needed for reuse, different technologies can be combined to remove target contaminants and harmful pathogens.
Membrane bioreactor technology continues to be a primary building block for water reuse applications. It is perfect for plants that don’t have a large footprint, because it allows for upgrades in treatment in existing tanks.
Ultrafiltration membranes can be used as a tertiary treatment step on the back end of conventional activated sludge facilities to upgrade quality.
Reverse osmosis is often part of the treatment train for high-quality reuse water due to its efficiency in removing salinity and many inorganic and organic contaminants. It is also a barrier to pathogens.
Electrodialysis removal is gaining momentum for streams with brine challenges. This technology is a great option for any wastewater stream that needs total dissolved solids (TDS) removal prior to reuse. It has a high recovery and low fouling tendency.
Ozone and biofiltration is an excellent means of removing trace chemical constituents without the creation of a brine waste stream.
Disinfection technologies, which include ozone and UV, are core to pathogen inactivation and are both used in advanced treatment processes.
As potable water reuse has gained traction, there has been an accompanying increase in the level of monitoring too. Total Organic Carbon, or TOC, analysers play an significant role in managing treatment across an entire flowsheet.
For even tougher-to-treat industrial waters or where brine discharges can be a problem, zero-liquid discharge technology can achieve around 98% water reuse.
We need to think beyond tradition and put an end to the linear use of water, said Stephen. “The continuum that exists in reusing water is a very interesting one.
“Every municipality has wastewater and the beauty of that is it is local and already exactly where water is needed – it is, after all, the waste from the use of water.
“So if you look at the options a community has for achieving a sustainable water supply, it is under their noses and the thing is, we don’t have to wait for the necessary technology to appear to do this properly and safety, because it already exists.
“The technology innovation has already taken place and today is about tailoring the right solutions for the unique challenge that exist in different places.”