Seeing the Value in “Waste”: A Guest Post by Matthew Verbyla

Cover image: Caio Reisewitz. Piaçabuçu, 2012. c-print mounted on Diasec. 70 7/8 x 89 3/8 inches.

On February 25 at 7 pm in the USF Patel Center, artist Caio Reisewitz and environmental engineer Matthew Verbyla will give a talk about water issues in Brazil. The work of Caio Reisewitz can be seen in USFCAM’s exhibition Histórias/Histories: Contemporary Art from Brazil, on view through March 5. Matthew Verbyla wrote this blog post about his work in Brazil converting sewage sludge into usable fuel.


SSDS schematic

All materials have value. As an environmental engineer, I look for the value in materials that are normally considered to be waste. Last year I spent six months in Minas Gerais, Brazil, working with Brazilian nonprofit Consciência Limpa to develop a prototype for a solar sludge drying system. Sludge is the solid material leftover from domestic sewage after treatment. You poop, flush the toilet, wash dishes and clothes, which sends water, soap, and countless other materials down the drain. If you live in a city, this noxious mixture of water and materials called sewage (wastewater) probably ends up at a centralized treatment plant. Engineers design systems to harbor millions of beneficial microorganisms that digest the solid material in your waste, which purifies the water so it can be reused or returned safely to the environment. However, the biomass of these microorganisms sinks to the bottom of the tanks, forming a thick material called sewage sludge.

Sewage sludge smells bad. It looks bad. It also contains harmful bacteria, viruses, and parasites. However, the sludge also contains lots of useful organic material that can be converted to energy. In many places throughout the world, sludge is dumped into the environment without treatment, contaminating ecosystems. Our solar sludge drying system heats the sludge chamber to 45-50°C using energy from the sun. This is hot enough to kill harmful bacteria, viruses, and parasites, and it helps dry out the sludge without the need for expensive and energy-intensive mechanized drying equipment. The dried and sanitized sludge can be pelletized and used as fuel briquettes to produce gas that can power an engine! Check out our video below to learn more about how this system works. For more information about what USF students and faculty are doing to reclaim valuable resources from “waste” products, join us through the Reclaim Network. We especially need photographers and videographers to help us communicate our research to non-engineers, policy makers, and the broader public!

2015-07-13 10.51.47.jpgPrototype of the solar-powered sludge drying system.

SSDS detail.jpgSludge is diverted into the greenhouse chamber. Cold air enters the system and is heated as it passes through the perforated heating panels, which are made of recycled aluminum, painted black and directed at the sun.

SSDS solar panel.jpg

IMG-20150813-WA0011.jpgA small solar panel powers fans, which force the heated air into the greenhouse chamber.

Matthew Verbyla
Postdoctoral Research Associate
Civil & Environmental Engineering
University of South Florida

verbyla profile photo

Acknowledgements: The construction of the pilot-scale solar sludge-drying system was funded by grant number APQ-03314-13 from the Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG), awarded to J.J. Gestão e Negócios, Ltda. Matthew Verbyla was supported by a United States Agency for International Development (USAID) Research & Innovations Fellowship, under Sub-Grant Award No. 2000004615. This work is based upon work supported by the U.S. National Science Foundation under Grant No. 1144244 (Graduate Research Fellowship Program). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of FAPEMIG, USAID or the U.S. National Science Foundation.

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