Using Coal Waste to Create Sustainable Concrete

New Coal Concrete Reduces Energy Demand, Greenhouse Emissions

Date: July 12, 2018
Source: Washington State University
Summary: Researchers have created a sustainable alternative to traditional concrete using coal fly ash, a waste product of coal-based electricity generation.

Chemical engineering student Ka Fung Wong looks at the data log, which is used to gather data from sensors buried under the concrete test plot.
Credit: WSU

Washington State University researchers have created a sustainable alternative to traditional concrete using coal fly ash, a waste product of coal-based electricity generation.

The advance tackles two major environmental problems at once by making use of coal production waste and by significantly reducing the environmental impact of concrete production.

Xianming Shi, associate professor in WSU's Department of Civil and Environmental Engineering, and graduate student Gang Xu, have developed a strong, durable concrete that uses fly ash as a binder and eliminates the use of environmentally intensive cement. They report on their work in the August issue of the journal, Fuel.

Reduces Energy Demand, Greenhouse Emissions

Production of traditional concrete, which is made by combining cement with sand and gravel, contributes between five and eight percent of greenhouse gas emissions worldwide. That's because cement, the key ingredient in concrete, requires high temperatures and a tremendous amount of energy to produce.

Fly ash, the material that remains after coal dust is burned, meanwhile has become a significant waste management issue in the United States. More than 50 percent of fly ash ends up in landfills, where it can easily leach into the nearby environment.

While some researchers have used fly ash in concrete, they haven't been able to eliminate the intense heating methods that are traditionally needed to make a strong material.

"Our production method does not require heating or the use of any cement," said Xu.

Molecular Engineering

This work is also significant because the researchers are using nano-sized materials to engineer concrete at the molecular level.

"To sustainably advance the construction industry, we need to utilize the 'bottom-up' capability of nanomaterials," said Shi.

The team used graphene oxide, a recently discovered nanomaterial, to manipulate the reaction of fly ash with water and turn the activated fly ash into a strong cement-like material. The graphene oxide rearranges atoms and molecules in a solution of fly ash and chemical activators like sodium silicate and calcium oxide. The process creates a calcium-aluminate-silicate-hydrate molecule chain with strongly bonded atoms that form an inorganic polymer network more durable than (hydrated) cement.

Aids Groundwater, Mitigates Flooding

The team designed the fly ash concrete to be pervious, which means water can pass through it to replenish groundwater and to mitigate flooding potential.

Researchers have demonstrated the strength and behavior of the material in test plots on the WSU campus under a variety of load and temperature conditions. They are still conducting infiltration tests and gathering data using sensors buried under the concrete. They eventually hope to commercialize the patented technology.

"After further testing, we would like to build some structures with this concrete to serve as a proof of concept," said Xu.

The research was funded by the U.S. Department of Transportation's University Transportation Centers and the WSU Office of Commercialization.

Story Source: Washington State University. "Using coal waste to create sustainable concrete: New coal concrete reduces energy demand, greenhouse emissions." ScienceDaily. ScienceDaily, 12 July 2018. https://www.sciencedaily.com/releases/2018/07/180712100513.htm.

Brewery Wastewater Transformed into Energy Storage

Date: October 7, 2016
Source: University of Colorado at Boulder
Summary: Engineers have developed an innovative bio-manufacturing process that uses a biological organism cultivated in brewery wastewater to create the carbon-based materials needed to make energy storage cells. This unique pairing of breweries and batteries could set up a win-win opportunity by reducing expensive wastewater treatment costs for beer makers while providing manufacturers with a more cost-effective means of creating renewable, naturally-derived fuel cell technologies.

CU Boulder engineers have developed an innovative bio-manufacturing process that uses a biological organism cultivated in brewery wastewater to create the carbon-based materials needed to make energy storage cells.

This unique pairing of breweries and batteries could set up a win-win opportunity by reducing expensive wastewater treatment costs for beer makers while providing manufacturers with a more cost-effective means of creating renewable, naturally-derived fuel cell technologies.

"Breweries use about seven barrels of water for every barrel of beer produced," said Tyler Huggins, a graduate student in CU Boulder's Department of Civil, Environmental and Architectural Engineering and lead author of the new study. "And they can't just dump it into the sewer because it requires extra filtration."

The process of converting biological materials, or biomass, such as timber into carbon-based battery electrodes is currently used in some energy industry sectors. But, naturally-occurring biomass is inherently limited by its short supply, impact during extraction and intrinsic chemical makeup, rendering it expensive and difficult to optimize.

However, the CU Boulder researchers utilize the unsurpassed efficiency of biological systems to produce sophisticated structures and unique chemistries by cultivating a fast-growing fungus, Neurospora crassa, in the sugar-rich wastewater produced by a similarly fast-growing Colorado industry: breweries.

"The wastewater is ideal for our fungus to flourish in, so we are happy to take it," said Huggins.

By cultivating their feedstock in wastewater, the researchers were able to better dictate the fungus's chemical and physical processes from the start. They thereby created one of the most efficient naturally-derived lithium-ion battery electrodes known to date while cleaning the wastewater in the process.

The findings were published recently in the American Chemical Society journal Applied Materials & Interfaces.

If the process were applied on a large scale, breweries could potentially reduce their municipal wastewater costs significantly while manufacturers would gain access to a cost-effective incubating medium for advanced battery technology components.

"The novelty of our process is changing the manufacturing process from top-down to bottom-up," said Zhiyong Jason Ren, an associate professor in CU Boulder's Department of Civil, Environmental and Architectural Engineering and a co-author of the new study. "We're biodesigning the materials right from the start."

Huggins and study co-author Justin Whiteley, also of CU Boulder, have filed a patent on the process and created Emergy, a Boulder-based company aimed at commercializing the technology.

"We see large potential for scaling because there's nothing required in this process that isn't already available," said Huggins.

The researchers have partnered with Avery Brewing in Boulder in order to explore a larger pilot program for the technology. Huggins and Whiteley recently competed in the finals of a U.S. Department of Energy-sponsored startup incubator competition at the Argonne National Laboratory in Chicago, Illinois.

The research was funded by the Office of Naval Research and came as a result of a unique cross-disciplinary collaboration between Ren's lab in CU Boulder's Department of Civil, Environmental and Architectural Engineering; Professor Se-Hee Lee's lab in CU Boulder's Department of Mechanical Engineering; and Justin Biffinger's lab at the Naval Research Laboratory in Washington, D.C.

"This research speaks to the spirit of entrepreneurship at CU Boulder," said Ren, who plans to continue experimenting with the mechanisms and properties of the fungus growth within the wastewater. "It's great to see students succeeding and creating what has the potential to be a transformative technology. Energy storage represents a big opportunity for the state of Colorado and beyond."

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Materials provided by University of Colorado at Boulder. Note: Content may be edited for style and length.

University of Colorado at Boulder. "Brewery wastewater transformed into energy storage." ScienceDaily. ScienceDaily, 7 October 2016. www.sciencedaily.com/releases/2016/10/161007120518.htm.

Wastewater to Irrigate, Fertilize and Generate Energy

Date: September 3, 2015
Source: Fraunhofer-Gesellschaft
Summary: To meet the requirements of Asian cities, researchers are adapting an idea they have already applied in Germany for comprehensive water management: developing a concept for reducing water use, treating wastewater and extracting fertilizer for a strip of coastline in the Vietnamese city of Da Nang

Agricultural areas in the Vietnamese city of Da Nang: in the future, residents can use purified wastewater to water their crops.
Credit: © Fraunhofer IGB

To meet the requirements of Asian cities, researchers are adapting an idea they have already applied in Germany for comprehensive water management: They are developing a concept for reducing water use, treating wastewater and extracting fertilizer for a strip of coastline in the Vietnamese city of Da Nang.

Urbanization is in full swing. Particularly in Asia, solutions are needed for feeding the growing population, supplying water and energy, and cleverly recycling waste wherever possible. In Vietnam, researchers from the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB in Stuttgart have adapted a wastewater treatment concept they developed in the DEUS 21 project to support the supply of water, energy and fertilizer.

Under the auspices of the German Society for International Cooperation GmbH (GIZ), the "Integrated Resource Management in Asian Cities: The Urban Nexus" project will now implement the innovative infrastructure along a strip of coastal land with some 200,000 residents in the Vietnamese city of Da Nang. Starting in the fall, 110 plots -- home to around 500 people -- are to be connected to a novel sewage network made up of vacuum pipes, which have a significantly smaller diameter than standard pipes. Wastewater is extracted with pumps, similar to the process used in trains and aircraft.

Until now, Da Nang's wastewater often flowed untreated into leaky ditches. Not only does this risk contaminating beaches, it also leaves untapped a valuable resource that the Fraunhofer researchers are now making accessible. Now for the first time, wastewater will be processed together with hotel kitchen waste; the resulting biogas will be used for cooking in hotel kitchens. Treated water will be used for urban agriculture -- meaning farmers will require less groundwater, reserves of which are at risk of becoming ever more saline as seawater is drawn in to replace the excessive volumes of freshwater being extracted during periods of drought. A further advantage is that nutrients found in the processed wastewater work as a natural fertilizer. So the novel system connects the pressing issues of supplying water, energy and food with little effort -- and the researchers achieve good results in each area. For example, with biogas: "At 45 liters per resident per day, our solution produces twice as much biogas as with traditional water treatment plants in Germany," says group manager Dr. Marius Mohr from the IGB.

Even the Wastewater Energy is Used

This concept sees wastewater purified biologically. "At the heart of the system are anaerobic bioreactors in which the organic component of wastewater ferments into biogas," Mohr explains. Bioreactors can also be combined with membrane filtration so that all larger particles, including the bacteria, remain inside the bioreactors. For cost reasons, this is not part of the initial plan for Da Nang.

The DEUS 21 concept was developed to maximize the recycling of wastewater and of the resources it contains. Not only can the biogas created in the anaerobic bioreactor be used for cooking, it can also be used to supply electricity and heat or to power vehicles. And because the wastewater remains relatively warm after processing, it is possible to draw additional thermal energy from it and supply this to households in cooler regions via a district heating network. "As another product of wastewater treatment nitrogen-phosphorus fertilizer can be won through a process of precipitation and ion exchange," Mohr explains.

The system could be implemented in many different regions, in particular where there is no sewer system or sewage treatment. "It's also suitable for export to areas with little water because it can be adapted to fit the needs of arid and semi-arid regions," Mohr adds.

Story Source:

The above post is reprinted from materials provided by Fraunhofer-Gesellschaft.

Fraunhofer-Gesellschaft. "Wastewater to irrigate, fertilize and generate energy." ScienceDaily. ScienceDaily, 3 September 2015. .