Changing the paradigm…wastewater treatment to resource recovery

Over the years, advanced wastewater treatment was driven by fears around public health; and later in emerging and sensitive areas, around better environmental protection driven through regulation. This drove proliferation and innovation in new membrane, specialty chemical and other treatment technologies to solve these issues.

Along with these advances, energy consumption and processes got more intensive - almost 40% of a municipality’s total operating expense is energy.

 Astoundingly, approximately 3% of electricity generated in the U.S.A, enough to power almost 7 million homes, is used to treat wastewater; it’s a mind-boggling figure, especially, when you take into account that the wastewater itself contains 3-4 times the energy in it than is required to treat it.

 This has caused us to turn the paradigm on its head. Can we exploit the currently untapped resources in wastewater, which are today considered a burden, and make these wastewater treatment plants, resource recovery facilities instead? Or, maybe even one step further…renewable energy plants for tomorrow?

 Today, using anaerobic digestion (utilizing bacteria in the absence of oxygen), we can breakdown organics in wastewater and bio-waste to generate methane. This methane can be used as fuel for a boiler, injected into a gas pipeline or burned in gas engines to produce electricity, which in turn can power the waste treatment plant itself and put energy back on the grid. Some municipalities augment the energy generation by co-digestion of food waste in addition to bio-solids. Valuable bi-products, or nutrient recovery (such as Phosphorus and Nitrogen), is also within reach. For municipalities, in addition to energy production and nutrient recovery, there is substantial reduction of haulage to landfills, eliminating substantive cost and environmental impact. Onsite renewable energy also guarantees energy security.

 New technologies and flow sheets, including hybrid membrane aerated biofilm reactors (MABR), are being piloted with a lot of promise. Not only are these systems lowering the energy required for treatment upfront, but are also extracting a lot more energy, which can be converted to heat or electricity and achieve energy neutrality or potentially net positive energy.

 It’s not a question of if, it’s a question of when, and I think it’s sooner than you think…the entire wastewater treatment space is primed to undergo a revolutionary change.

Next time you hear the term “wastewater,” think about it as “opportunity water and energy.”