FAQ

FREQUENTLY ASKED QUESTIONS

Do You Have Questions?  We Have Answers! 


Below you’ll find answers to the most common questions we could think of regarding energy recycling.  If you can’t find the answer you’re looking for, please feel free to contact us.

  • What is STEU?

    Sewage Thermal Energy Utilization (STEU) represents a transformative approach to energy efficiency and sustainability. The term STEU was coined in the 2019 report by the American Water Works Association - Research Foundation (AWWA-RF). The concept goes beyond the traditional view of sewage as waste heat, recognizing its dual capability as a source for productive heating and cooling. STEU is a paradigm shift in acknowledging the untapped potential of thermal energy in sewage systems – energy that has been routinely disregarded in the past. LEARN MORE...

  • You say energy recycling - Can one actually recycle energy?

    Yes, energy can be reclaimed and reused. It is important to understand all of the laws of thermodynamics but low quality energy can be reclaimed and made into higher quality energy.  This effort requires energy itself but thermal energy can be collected and reclaimed.  

  • Sewage Thermal Energy Use (STEU) seems to imply you are using sewage to heat my house. Are you putting sewage back into my house?

    No, the thermal energy is being collected from sewage and beneficially used.  If one were to cut into a STEU pipe in a building one would not find sewage.

  • If you don’t recycle the sewage, how do you gain access to the heat?

    We use thermodynamic devices called heat exchangers. These units either remove heat or add heat to the sewage. This is the dirty part of the process.

  • If sewage is 68 °F (20 °C) then how can you make it hotter since fluids do not become hotter on their own?

    The second law of thermodynamics applies.  We use a thermodynamic device called a heat pump that pumps the temperature from cold to hot, hence its name.  This is done by applying energy (work) into the process. The advantage is that the device requires much less input energy for the amount of heat obtained than any other heating device made. 

  • Who owns the sewage heat?

    Although it is a common property because we all contribute to it, the sewer authority owns the sewer and therefore its contents.  It is important to note this legal distinction has not been widely explored by the court (Adjudication) or law (Legislation).   

  • Has anyone used sewage as a heat source before?

    Yes, there are many examples of this application.  Refer to our photo gallery to see many examples of this technology.

STEN BLOG - Recent Posts

Learning About the Environmental Benefits of Sewer Thermal Technology
By David Valentine, STEN Director October 10, 2024
Sewer thermal technology is like turning a source of waste heat into something useful and environmentally friendly, making our energy systems more efficient and sustainable. By using these basic methods, you can gain a broader understanding of the introductory concepts of environmental benefits of sewer thermal technology.
Large-Scale Wastewater Source Heat Pumps Have Considerable Market Potential
By STEN DIRECTORS August 21, 2024
We are frequently asked how much a wastewater heat recycling system costs compared to other low carbon options. The answer is that every project is unique and so generalizations are difficult to make. However, the chart below demonstrates the results...
Wastewater is an Overlooked & Undervalued Existing Asset
By Chris Hubbard, STEN Director April 12, 2024
In urban environments, where the demand for energy is high and resources are often stretched, innovative solutions like wastewater heat recovery are gaining attention for their potential to enhance energy efficiency...
Understanding Wastewater Heat Recovery to Maximize Energy Efficiency
By Constantine Leotsakos, Director of Membership March 27, 2024
In the quest for sustainability and efficiency, industries and municipalities are increasingly turning to innovative methods to harness every available resource. Wastewater, often generated from industrial processes or municipal facilities, carries a significant amount of heat energy, which would otherwise go to waste...
Strengthen the Bottom Line & Contribute to a More Sustainable Future
By Kevin Fitzsimmons, STEN Director March 18, 2024
Wastewater heat recovery, once seen as a mere byproduct of sewage treatment, is now being recognized as a significant untapped resource with immense economic potential. As industries and municipalities seek sustainable solutions to reduce energy costs and carbon footprints, wastewater heat recovery presents itself as a promising avenue...
Harnessing the Power of Thermal Energy for a Greener Future
By David Valentine, STEN Director March 13, 2024
Wastewater heat recovery is a promising technology that offers significant environmental benefits by harnessing the thermal energy present in wastewater. As societies strive to reduce their carbon footprint and transition towards sustainable energy sources, this innovative approach presents an opportunity to utilize a readily available and often overlooked resource...
Unlocking Profit + Sustainability of Wastewater Heat Recovery
By Nick Meeten March 4, 2024
In the pursuit of sustainable and economically viable urban development, city authorities are increasingly turning to innovative solutions. One such solution that has gained traction in recent years is the recycling of heat from wastewater...
Unveiling the Future of Water Treatment
By Robert Zarnetske, STEN Director of Policy February 26, 2024
This article delves into the evolving world of wastewater treatment with a particular focus on the technologies employed in heat recapture, a crucial aspect of sustainable water management.
LNG Carrier Ship Sewage Thermal Energy Use STEN
By Paul Kohl, STEN Chairman February 12, 2024
Technologies like sewer thermal recapture is not just environmentally sound; it represents a practical solution to reduce our fossil fuel dependency. Utilizing all the heat we already produce (and not just flushing it down the drain) could enhance energy security and economic resilience...
Public-Private Partnership (P3s) & Sewer Heat
By Robert Zarnetske, Director of Policy February 9, 2024
Protecting public health is the foremost priority for water and wastewater service providers. However, a deeper understanding of water utilities can also reveal revenue opportunities and save tax dollars...
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