Fuel From Sewage is the Future -- And It's Closer Than You Think

Technology Converts Human Waste into Bio-Based Fuel

Date: November 2, 2016
Source: Pacific Northwest National Laboratory
Summary: It may sound like science fiction, but wastewater treatment plants across the United States may one day turn ordinary sewage into biocrude oil, thanks to new research. The technology, hydrothermal liquefaction, mimics the geological conditions Earth uses to create crude oil, using high pressure and temperature to achieve in minutes something that takes Mother Nature millions of years.

Biocrude oil, produced from wastewater treatment plant sludge, looks and performs virtually like fossil petroleum.
Credit: Courtesy of WE&RF

It may sound like science fiction, but wastewater treatment plants across the United States may one day turn ordinary sewage into biocrude oil, thanks to new research at the Department of Energy's Pacific Northwest National Laboratory.

The technology, hydrothermal liquefaction, mimics the geological conditions Earth uses to create crude oil, using high pressure and temperature to achieve in minutes something that takes Mother Nature millions of years. The resulting material is similar to petroleum pumped out of the ground, with a small amount of water and oxygen mixed in. This biocrude can then be refined using conventional petroleum refining operations.

Wastewater treatment plants across the U.S. treat approximately 34 billion gallons of sewage every day. That amount could produce the equivalent of up to approximately 30 million barrels of oil per year. PNNL estimates that a single person could generate two to three gallons of biocrude per year.

Sewage, or more specifically sewage sludge, has long been viewed as a poor ingredient for producing biofuel because it's too wet. The approach being studied by PNNL eliminates the need for drying required in a majority of current thermal technologies which historically has made wastewater to fuel conversion too energy intensive and expensive. HTL may also be used to make fuel from other types of wet organic feedstock, such as agricultural waste.

Using hydrothermal liquefaction, organic matter such as human waste can be broken down to simpler chemical compounds. The material is pressurized to 3,000 pounds per square inch -- nearly one hundred times that of a car tire. Pressurized sludge then goes into a reactor system operating at about 660 degrees Fahrenheit. The heat and pressure cause the cells of the waste material to break down into different fractions -- biocrude and an aqueous liquid phase.

"There is plenty of carbon in municipal waste water sludge and interestingly, there are also fats," said Corinne Drennan, who is responsible for bioenergy technologies research at PNNL. "The fats or lipids appear to facilitate the conversion of other materials in the wastewater such as toilet paper, keep the sludge moving through the reactor, and produce a very high quality biocrude that, when refined, yields fuels such as gasoline, diesel and jet fuels."

In addition to producing useful fuel, HTL could give local governments significant cost savings by virtually eliminating the need for sewage residuals processing, transport and disposal.

"The best thing about this process is how simple it is," said Drennan. "The reactor is literally a hot, pressurized tube. We've really accelerated hydrothermal conversion technology over the last six years to create a continuous, and scalable process which allows the use of wet wastes like sewage sludge."

An independent assessment for the Water Environment & Reuse Foundation calls HTL a highly disruptive technology that has potential for treating wastewater solids. WE&RF investigators noted the process has high carbon conversion efficiency with nearly 60 percent of available carbon in primary sludge becoming bio-crude. The report calls for further demonstration, which may soon be in the works.

PNNL has licensed its HTL technology to Utah-based Genifuel Corporation, which is now working with Metro Vancouver, a partnership of 23 local authorities in British Columbia, Canada, to build a demonstration plant.

"Metro Vancouver hopes to be the first wastewater treatment utility in North America to host hydrothermal liquefaction at one of its treatment plants," said Darrell Mussatto, chair of Metro Vancouver's Utilities Committee. "The pilot project will cost between $8 to $9 million (Canadian) with Metro Vancouver providing nearly one-half of the cost directly and the remaining balance subject to external funding."

Once funding is in place, Metro Vancouver plans to move to the design phase in 2017, followed by equipment fabrication, with start-up occurring in 2018.

"If this emerging technology is a success, a future production facility could lead the way for Metro Vancouver's wastewater operation to meet its sustainability objectives of zero net energy, zero odours and zero residuals," Mussatto added.

In addition to the biocrude, the liquid phase can be treated with a catalyst to create other fuels and chemical products. A small amount of solid material is also generated, which contains important nutrients. For example, early efforts have demonstrated the ability to recover phosphorus, which can replace phosphorus ore used in fertilizer production.

Story Source:

Materials provided by Pacific Northwest National Laboratory. Note: Content may be edited for style and length.
Pacific Northwest National Laboratory. "Fuel from sewage is the future -- and it's closer than you think: Technology converts human waste into bio-based fuel." ScienceDaily. ScienceDaily, 2 November 2016. www.sciencedaily.com/releases/2016/11/161102134504.htm

World's First Industrial-Scale Waste-to-Biofuels Facility

By Ben Coxworth | June 20, 2014

Thanks to its extensive composting and recycling facilities, the city of Edmonton, Canada is already diverting approximately 60 percent of its municipal waste from the landfill. That figure is expected to rise to 90 percent, however, once the city's new Waste-to-Biofuels and Chemicals Facility starts converting garbage (that can't be composted or recycled) into methanol and ethanol. It's the world's first such plant to operate on an industrial scale, and we recently got a guided tour of the place.

The process begins with garbage trucks dumping their loads on the tipping floor at the Integrated Processing and Transfer Facility. The trash is manually and mechanically sorted, with things like appliances being set aside for electronic parts recycling and e-waste disposal, while organic matter heads off to the Composting Facility.

Recyclable materials are already pre-separated by citizens as part of the city's blue bag program. They avoid the garbage stream entirely, going straight to the Materials Recovery Facility for recycling.

Soon, though, high-carbon materials such as wood, fabric and discarded plastic will be getting shredded into Refuse Derived Fuel (RDF), also known as "garbage fluff." It will be transferred to the Waste-to-Biofuels and Chemicals Facility, which is owned and operated by Enerkem Alberta Biofuels.

There, it will be heated in a low-oxygen atmosphere. This will cause its chemical bonds to break (without the material actually burning), releasing their carbon and hydrogen content to form what's known as syngas. This will in turn be cleaned up and converted into chemical products and biofuels – such as methanol and ethanol.

The Waste-to-Biofuels and Chemicals Facility is scheduled to go online in the next several weeks. It is ultimately expected to convert 100,000 tonnes (110,231 tons) of municipal solid waste into 38 million liters (10 million gallons) of biofuels and chemicals annually.

You can see our video tour of the facility below, conducted by the Edmonton Waste Management Centre's Education Programs Co-ordinator, Garry Spotowski. There are also photos of the process in the gallery.

The video can be viewed at: https://www.youtube.com/watch?v=LKKweSAm1Ks

Source: http://www.gizmag.com/edmonton-waste-to-biofuels-facility-video-tour/32630/

Study: Fuels from Corn Waste Not Better Than Gas

Monday Apr 21, 2014 | Dina Cappiello for The Associated Press

Credit: AP Photo/The University of Nebraska-Lincoln.

WASHINGTON (AP) — Biofuels made from the leftovers of harvested corn plants are worse than gasoline for global warming in the short term, a study shows, challenging the Obama administration's conclusions that they are a much cleaner oil alternative and will help combat climate change.

A $500,000 study paid for by the federal government and released Sunday in the peer-reviewed journal Nature Climate Change concludes that biofuels made with corn residue release 7 percent more greenhouse gases in the early years compared with conventional gasoline.

While biofuels are better in the long run, the study says they won't meet a standard set in a 2007 energy law to qualify as renewable fuel.

The conclusions deal a blow to what are known as cellulosic biofuels, which have received more than a billion dollars in federal support but have struggled to meet volume targets mandated by law. About half of the initial market in cellulosics is expected to be derived from corn residue.

The biofuel industry and administration officials immediately criticized the research as flawed. They said it was too simplistic in its analysis of carbon loss from soil, which can vary over a single field, and vastly overestimated how much residue farmers actually would remove once the market gets underway.

"The core analysis depicts an extreme scenario that no responsible farmer or business would ever employ because it would ruin both the land and the long-term supply of feedstock. It makes no agronomic or business sense," said Jan Koninckx, global business director for biorefineries at DuPont. Later this year the company is scheduled to finish a $200 million-plus facility in Nevada, Iowa, that will produce 30 million gallons of cellulosic ethanol using corn residue from nearby farms. An assessment paid for by DuPont said that the ethanol it will produce there could be more than 100 percent better than gasoline in terms of greenhouse gas emissions.

The research is among the first to attempt to quantify, over 12 Corn Belt states, how much carbon is lost to the atmosphere when the stalks, leaves and cobs that make up residue are removed and used to make biofuel, instead of left to naturally replenish the soil with carbon. The study found that regardless of how much corn residue is taken off the field, the process contributes to global warming. "I knew this research would be contentious," said Adam Liska, the lead author and an assistant professor of biological systems engineering at the University of Nebraska-Lincoln. "I'm amazed it has not come out more solidly until now."

The Environmental Protection Agency's own analysis, which assumed about half of corn residue would be removed from fields, found that fuel made from corn residue, also known as stover, would meet the standard in the energy law. That standard requires cellulosic biofuels to release 60 percent less carbon pollution than gasoline.

Cellulosic biofuels that don't meet that threshold could be almost impossible to make and sell. Producers wouldn't earn the $1 per gallon subsidy they need to make these expensive fuels and still make a profit. Refiners would shun the fuels because they wouldn't meet their legal obligation to use minimum amounts of next-generation biofuels.

EPA spokeswoman Liz Purchia said in a statement that the study "does not provide useful information relevant to the life cycle greenhouse gas emissions from corn stover ethanol."

But an AP investigation last year found that the EPA's analysis of corn-based ethanol failed to predict the environmental consequences accurately.

The departments of Agriculture and Energy have initiated programs with farmers to make sure residue is harvested sustainably. For instance, farmers will not receive any federal assistance for conservation programs if too much corn residue is removed.

A peer-reviewed study performed at the Energy Department's Argonne National Laboratory in 2012 found that biofuels made with corn residue were 95 percent better than gasoline in greenhouse gas emissions. That study assumed some of the residue harvested would replace power produced from coal, reducing greenhouse gas emissions, but it's unclear whether future biorefineries would do that.

Liska agrees that using some of the residue to make electricity, or planting cover crops, would reduce carbon emissions. But he did not include those in his computer simulation.

Still, corn residue is likely to be a big source early on for cellulosic biofuels, which have struggled to reach commercial scale. Last year, for the fifth time, the EPA proposed reducing the amount required by law. It set a target of 17 million gallons for 2014. The law envisioned 1.75 billion gallons being produced this year.

"The study says it will be very hard to make a biofuel that has a better greenhouse gas impact than gasoline using corn residue," which puts it in the same boat as corn-based ethanol, said David Tilman, a professor at the University of Minnesota who has done research on biofuels' emissions from the farm to the tailpipe.

Tilman said it was the best study on the issue he has seen so far.

Researcher Looks into Wastewater Zooplankton as Biofuel Feedstock

February 5, 2014 -- With dwindling non-renewable fuel sources creating an enormous energy challenge, the search is on to develop sustainable, renewable types of energy such as solar, wind and biofuel. One of the recent developments in this field comes from New York's Clarkson University, where new findings suggest that small organisms found in wastewater treatment lagoons could be used as biofuel feedstock.

The research was carried out by PhD student Stefanie Kring, who examined sunlit lagoons in Canton, New York during the summer. She found them to be rich in zooplankton, also found in other water bodies such as lakes and rivers, although algae was conspicuously absent.

Its absence was due to the fact that the plankton fed on algae, and had no predators in the lagoons, leading to their high concentration. These small organisms could be useful in the making of biofuel because when they feed, they accumulate oil in their bodies, and it's easier to extract that oil from them than it is from algae.

Besides biofuel, the study suggests that protein and polyunsaturated fatty acids could be harvested from zooplankton biomass. For that, lagoons would need to be redesigned to perform tasks other than wastewater treatment.

Further lifecycle and economic assessments are needed to determine the feasibility of harvesting zooplankton, but there is potential. "These zooplankton grow fast, they select algae from among all of the other particles present in the water, " said Kring. "Collecting zooplankton from water is much easier than collecting microscopic algae, due to their larger size."

Details of the research recently appeared in the journal Environmental Technology.

Source: Clarkson University.

Desert Plants to be Put to the Test for Aviation Biofuel Production

Whenever the topic of plant-derived biofuels is raised, the issue of turning valuable arable land over to the task of growing feedstock is generally not far behind. A discovery by the Sustainable Bioenergy Research Consortium (SRBC) that desert plants fed by seawater can produce biofuel more efficiently than other well-known feedstocks could help alleviate such concerns.

The SRBC, which is affiliated with the Masdar Institute of Science and Technology in Abu Dhabi, is receiving funding from Boeing, Etihad Airways and Honeywell UOP to develop and commercialize a sustainable biofuel that emits 50 to 80 percent less carbon through its lifecycle than fossil fuels. Plants called halophytes, which are highly salt tolerant, could be the answer.

SRBC researchers found that halophyte seeds contain oil suitable for biofuel production and that the entire shrub-like plant can be turned into biofuel more effectively than many other feedstocks.

To test their findings, the SRBC team will create a test ecosystem over the coming year that will see two crops of halophytes planted in the sandy soil found in Abu Dhabi. The test site will use waste seawater from a fish and shrimp farm to nourish the plants, with the water then flowing into a field of mangroves before being returned to the ocean.

"The UAE has become a leader in researching desert land and seawater to grow sustainable biofuel feedstocks, which has potential applications in other parts of the world," says Dr. Alejandro Rios, Director of the SBRC. "This project can have a global impact, since 97 percent of the earth's water is ocean and 20 percent of the earth's land is desert."

Source: Masdar Institute