Where Are the Big Breakthroughs in Water and Wastewater Treatment?

Research is steadily pushing the boundaries of performance and efficiency in wastewater treatment. But where are the real game-changers?

Twenty-four years ago, Nicholas Negroponte wrote a landmark book, Being Digital, that explored the impact of digital technology on work, entertainment, social life and commerce.

I read the book a few years after it was published, and what I most remember about it, two decades later, is the author’s commentary on research and development and how digital was changing attitudes toward improvements in performance, speed and efficiency.

In the digital world, he asserted, people were no longer interested in incremental change — an extra 2 miles per gallon from a car, a 3 percent cost reduction, a few minutes’ time savings. No, they were interested in quantum leaps, blow-the-doors-off improvements. Think iPhone from Apple versus flip phone.

Seeking game-changers

People in every industry look constantly to improve, but big leaps ahead are harder in established processes than in entirely new sectors. For example, in recent decades, automotive fuel efficiency has improved, but it hasn’t doubled or tripled. Mechanical constraints and laws of physics get in the way.

So if we’re looking for game-changers in the wastewater sector, they will be elusive. We have to dial down expectations for what game-changing actually means. There will always be improved bar screens and grit collectors, more efficient blowers, more precise instruments, better belt presses. But what game-changers are in the research pipeline, or already on the market, for clean-water plants? Here are a few that have caught my attention.

SUEZ offers an entirely new approach to aeration that doesn’t depend on bubbles, which float to the surface and then are gone. ZeeLung technology aerates activated sludge basins using a gas-permeable media to deliver oxygen to a biofilm on the media surface. The company promotes this largely for plant upgrades, saying it can provide up to 50 percent more treatment capacity in existing tankage, improve oxygen transfer by four times over fine-bubble aeration and increase energy efficiency by half. Those benefits of course would translate to new construction.

NVP Energy has developed a treatment technology that removes COD and BOD while producing renewable energy as biogas. It is suited for applications in the municipal and food and drink sectors. The company says the process can reduce energy costs and sludge production by up to 90 percent versus activated sludge treatment. It uses specialized anaerobic granular biofilms to convert organics to biogas without heat inputs so all energy produced can be used to generate heat and electricity.

Centrisys/CNP promotes the PONDUS thermo-chemical hydrolysis process for biosolids treatment. In a reactor upstream from the digesters, hot water and caustic break the cell membranes in waste activated sludge. Being more readily digestible, this material enables the digestion process to increase biogas production by 20 to 25 percent. Polymer consumption is reduced by 15 to 20 percent, and the dewatered solids cake is drier by 3 to 5 percentage points.  

As for things in the pipeline, there’s always talk about using algae for wastewater treatment. Now a study at the University of Arkansas has found that an algae species called Chlorella vulgaris can remove both nitrogen and phosphorus from wastewater even if one or the other is in short supply. A barrier to treatment with algae has been that the nutrient content of wastewater can be highly variable, and most algae need both nutrients to be present consistently in order to function. This potential breakthrough is still a long way from practical application.

Patience required

The trouble with improvements like these, even those already available, is that there’s so much legacy infrastructure, so many plants doing things in the best ways possible when built 20 or 30 years ago. It’s a lot to ask a community to spend millions to replace a process that works well, and meets permit, with something shiny and new. If your mobile phone becomes outdated, you can toss it aside and replace it with the latest and greatest. You can’t do that with a clean-water plant.

So, with no disrespect to Being Digital, perhaps we’re best off accepting that even as game-changing technologies emerge, their adoption will take time, and we’ll see the benefit not next year, but over decades. That’s not a hard concept to live with.


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