Ethical Dilemma Say Researchers

14 April 2011

Second generation biofuels that use waste as a feedstocks could be the answer to ‘unethical practices’ that are encouraged by current policies on biofuels, according a report by the Nuffield Council on Bioethics.

The UK based Nuffield Council on Bioethics examines ethical issues raised by new developments in biology and medicine, and in 2009 established a working party to examine the ethical issues raised by biofuels. The report – Biofuels: ethical issues – has been published recently following an 18 month inquiry.

According to the report policies such as the European Renewable Energy Directive (RED) are particularly weak when it comes to protecting the environment, reducing greenhouse gas emissions and avoiding human rights violations in developing countries.

Critically, the report also claims that such policies include few incentives for the development of new biofuel technologies that could help avoid such problems.

“Biofuels are one of the only renewable alternatives we have for transport fuels such as petrol and diesel, but current policies and targets that encourage their uptake have backfired badly,” said Professor Joyce Tait, who led the inquiry.

Tait cites the rapid expansion of biofuels production in the developing world as a cause of deforestation and displacement of indigenous people, and adds that a more sophisticated strategy that considers the wider consequences of biofuel production is needed.

However, the report goes on to say that research into a second generation of biofuels has the potential to provide feedstocks that:

• Do not compete with food
• Have a high energy yield with low inputs of water, land and fertiliser etc.
• Do not negatively affect the environment or local populations
• Can be produced in sufficient quantities to allow economically viable biofuels production.

New research

1. Biofuels development should not be at the expense of human rights
2. Biofuels should be environmentally sustainable
3. Biofuels should contribute to a reduction of greenhouse gas emissions
4. Biofuels should adhere to fair trade principles
5. Costs and benefits of biofuels should be distributed in an equitable way.

Small scale, distributed anaerobic digestion plants could offer an environmentally and economically stable solution for locally produced biogas. In Germany government incentives have led to the development of over 6000 anaerobic digestion (AD) facilities, generating twice as much power as all of the country’s waste to energy facilities combined.

However many of these are large scale, 1 MW plus facilities, and the proliferation of such plants has affected both tipping fees for food waste – which have fallen from between Eur 60 to 80 per tonne down to Eur 10 to 20 per tonne – and biocrop prices to such an extent as to put many at risk of becoming economically unviable.

According to Craig Benton of Composting and Recycling Consultants, mini-biogas facilities could offer the ideal solution for farm waste. Speaking at the Energy from Biomass and Waste Conference in London today, Benton claimed that most vendors of anaerobic digestion and biogas equipment offer systems starting at around 250 kW.

In most farm applications, such systems lead to a dependence on importing feedstocks from the surrounding area which can be economically risky. However, Benton claimed that a new system from Austrian firm, Bio4gas could offer the ideal solution. Available in two sizes – 20/25 kW and 50 kW – the system enables farmers to use animal slurry from their own farm to generate heat, power and digestate. At the heart of the product is the patented ‘Thermal Gas Lift’ – a passive mixing system that Benton said offers reduced energy consumption through the use of gas pressure to force the slurry mixture through holes in the bottom.

The smaller of the two systems features a 220 cubic metre tank that is dug into the ground and holds 180 cubic metres of material. In addition a double chamber digester produces more biogas than a single tank.

According to Benton the advantages offered by a more distributed approach to biogas are significant, with potential returns on investment ranging between 12.5% and 16.4% based on conservative figures. Benton added that small scale biogas production could free the operator from the “whims of the market”, insulating them from rising biocrop prices and the prospect of falling tipping fees. Additionally, as all of the feedstock is sourced from the host farm itself, the digestate can be used to fertilise the farmer’s own land with no solid waste permit or license is required

On Crude ‘Oil’ From Pig Manure

Science (June 17, 2008) — After a close examination of crude oil made from pig manure, chemists at the National Institute of Standards and Technology (NIST) are certain about a number of things. Most obviously, “This stuff smells worse than manure,” says NIST chemist Tom Bruno.

But a job’s a job, so the NIST team has developed the first detailed chemical analysis revealing what processing is needed to transform pig manure crude oil into fuel for vehicles or heating. Mass production of this type of biofuel could help consume a waste product overflowing at U.S. farms, and possibly enable cutbacks in the nation’s petroleum use and imports. But, according to a new NIST paper, pig manure crude will require a lot of refining.

The ersatz oil used in the NIST analyses was provided by engineer Yuanhui Zhang of the University of Illinois Urbana-Champaign. Zhang developed a system using heat and pressure to transform organic compounds such as manure into oil.

As described in the new paper, Bruno and colleagues determined that the pig manure crude contains at least 83 major compounds, including many components that would need to be removed, such as about 15 percent water by volume, sulfur that otherwise could end up as pollution in vehicle exhaust, and lots of char waste containing heavy metals, including iron, zinc, silver, cobalt, chromium, lanthanum, scandium, tungsten and minute amounts of gold and hafnium. Whatever the pigs eat, from dirt to nutritional supplements, ends up in the oil.

While the thick black liquid may look like its petroleum-based counterparts, the NIST study shows that looks can be deceiving. “The fact that pig manure crude oil contains a lot of water is unfavorable. They would need to get the water out,” Bruno says.

The measurements were made with a new NIST test method and apparatus, the advanced distillation curve, which provides highly detailed and accurate data on the makeup and performance of complex fluids. A distillation curve charts the percentage of the total mixture that evaporates as a sample is slowly heated. Because the different components of a complex mixture typically have different boiling points, a distillation curve gives a good measure of the relative amount of each component in the mixture. NIST chemists enhanced the traditional technique by improving precision and control of temperature measurements and adding the capability to analyze the chemical composition of each boiling fraction using a variety of advanced methods.

NIST researchers analyzed the graphite-like char remaining after the distillation by bombarding it with neutrons, a non-destructive way of identifying the types and amounts of elements present. Two complementary neutron methods detected the heavy metals listed above.

Bruno and colleagues currently spend much of their time analyzing military jet fuels and are not planning a major foray into pig manure. But Bruno concedes that the effort may have a payoff. “Who knows, it might help decrease the nuisance of manure piles.”

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Chicken manure to energy

Environmentally friendly, climate neutral and reliable: For the first time ever on display world wide at VIV Europe will be a gasification system which transforms biomass for example from poultry manure into energy. The clou of the Big Dutchman innovation is that, except for nitrogen, all the components which are important for fertilisation are preserved in the residual ash. Genuine dual use is thus achieved – quite independently of wind and sunshine.

The manure is dried, pressed into pellets and conveyed to a gasifier where it is converted into gas by means of thermochemical conversion. The only by-product which remains is ash – which is a very valuable fertiliser. Subsequently the energy produced in this way is processed in the combined heat and power plant (CHP) to generate electricity and heat. Furthermore, in addition to chicken manure, other by-products such as digestate from biogas plants or sugar cane can also be used for the same purpose.

The result is extremely impressive: The amount of energy produced in a 150 kW gasifier allows to supply thermal energy for 25 households for more than one year (maximum 10 kW heat output) and to provide 200 households one year long with electricity (at an annual average use of 0.75 kW per household).

Hall 12C.050

150 kW gasification system with conveyor belt, switching and control cabinet, gasifier, gas cooling and gas cleaning (from left to right)

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From Food Industry Waste

Science (Mar. 31, 2009) — The AZTI-Tecnalia technological centre, experts in food research, have put a biogas plant into operation in order to investigate novel systems of sustainable energy production based on the use of waste and sub-products from the food industry.

This new plant exploits the enormous potential of obtaining biogas from the organic matter contained in agricultural food waste, and will help the food industry to reduce the environmental impact caused by organic waste.

The plant, located at the AZTI-Tecnalia premises in Derio, aims to obtain biogas rich in methane by the process of anaerobic digestion* of the organic material contained in the sub-products from food, in order to transform it into electrical and heat energy. In the same way, for 2010, the technological centre foresees adapting the plant and making a commitment to that renewable source of energy which has seen the greatest surge in recent years: hydrogen. So, the aim is to be able to obtain hydrogen and methane from the same combined fermentation process.

AZTI-Tecnalia specialists are thus researching the viability of obtaining benefit from a number of agricultural food sub-products, alone or in combination (co-digestion) with other elements from various sources, such as sludge from purifying plants or food waste from mass consumption. Amongst others are mixtures from animal husbandry silage (purines), together with waste from agricultural food industries (leftovers from fruit and vegetable markets, milk whey, fish ends, aquaculture waste, etc.

With the biogas plant it is possible to reduce the environmental impact caused by organic waste. The emissions of greenhouse effect gases into the atmosphere are reduced, smells are considerably reduced and the final value of the waste is enhanced, As a consequence, the industry can adapt itself to environmental and social requisites, at the same time as its processes are more efficient through making better use of available resources.

The plant is available to government bodies and to food enterprises and environmental services who are interested in developing R+D projects applied to the energy valuation of food sub-products, with the aim of obtaining information for decision-making in the installation of this kind of plant at an industrial scale.

AZTI-Tecnalia is supporting the food industry in sustainable development, implementing measures to enhance its environmental performance. The biogas plant complements the activities undertaken by the centre at its food processing pilot plant, in which valuation trials of sub-products as new sources of raw materials for transformed foodstuffs are also carried out. Likewise, more profitable and innovative options are being sought in order to manage subproducts and waste generated by the food industry and studies of the Life Cycle Analysis (LCA) of the products are undertaken, analysing where the main costs and environmental impacts lie, and proposing, in consequence, situations for the enhancement and optimisation of the process.

* Anaerobic digestion is a biological process which transforms organic material into biogas and into a digested sludge, which can be used as organic enhancement in agricultural applications. Biogas mainly consists of carbon dioxide and methane, the latter with a high calorific value and which, thereby, can be used as a renewable source of electrical and/or thermal energy, or as a fuel for vehicles.

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Science (Aug. 22, 2009) — High-rate digestion with microfiltration is state-of-the-art in large sewage plants. It effectively removes accumulated sludge and produces biogas to generate energy. A study now reveals that even small plants can benefit from this process.

Sewage plants remove organic matter from wastewater. If the accumulating sludge decays, biogas is generated as a by-product. However, only 1156 of the 10,200 sewage plants in Germany have a digestion tank. Smaller operations, especially, baulk at the costs of a new digestion tank. Instead, they enrich the sludge with oxygen in the existing activation basin, and stabilize it.

“Activation basins require a lot of electricity. At the same time, enormous energy potential is lost, since no biogas is produced,” says Dr. Brigitte Kempter-Regel of the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB in Stuttgart. “A sewage plant eats up more electricity in the municipalities than their hospitals do.”

In a cost-benefit-study Dr. Kempter-Regel has shown that it also pays small sewage plants to transfer to more energy-efficient processes – even if they have to invest in a sludge digestion unit. “Based on a sewage plant for 28,000 inhabitants, we calculate that the plant can reduce its annual waste management costs from 225,000 euros by as much as 170,000 euros if sludge is decayed in a high-rate digestion unit with microfiltration, as opposed to treating it aerobically,” she says.

This process was developed at IGB and is much more effective than conventional digestion. Instead of the usual 30 to 50 days, sludge only remains in the tower for five to seven days. Around 60 percent of the organic matter is converted into biogas – the spoil is approximately a third more than in the traditional digestion process. The biogas obtained can be used to operate the plant, which, in the case study, would cut energy costs by at least 70,000 euros each year. High-rate digestion has the added advantage of producing less residual sludge needing disposal.

“This saves the operator another 100,000 euros,” says Kempter-Regel. In addition to high energy prices, budgets are also being hit hard by increasing waste management costs. The use of residual sludge in agriculture is controversial, and slurry can no longer be disposed of on landfills; burning the sludge is a very expensive alternative. So an effective reduction of sludge through digestion pays off. Even small sewage plants have already followed the recommendation of the Stuttgart Institute and converted to the high-rate digestion process.

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Within Pennies a Gallon

of Being Competitive

Science (May 20, 2010) — Existing technology can produce biodiesel fuel from municipal sewage sludge that is within a few cents a gallon of being competitive with conventional diesel refined from petroleum, according to an article in ACS’ Energy & Fuels. Sludge is the solid material left behind from the treatment of sewage at wastewater treatment plants.

David M. Kargbo points out in the article that demand for biodiesel has led to the search for cost-effective biodiesel feedstocks, or raw materials. Soybeans, sunflower seeds and other food crops have been used as raw materials but are expensive. Sewage sludge is an attractive alternative feedstock — the United States alone produces about seven million tons of it each year. Sludge is a good source of raw materials for biodiesel. To boost biodiesel production, sewage treatment plants could use microorganisms that produce higher amounts of oil, Kargbo says. That step alone could increase biodiesel production to the 10 billion gallon mark, which is more than triple the nation’s current biodiesel production capacity, the report indicates.

The report, however, cautions that to realize these commercial opportunities, huge challenges still exist, including challenges from collecting the sludge, separation of the biodiesel from other materials, maintaining biodiesel quality, soap formation during production, and regulatory concerns.

With the challenges addressed, “Biodiesel production from sludge could be very profitable in the long run,” the report states. “Currently the estimated cost of production is $3.11 per gallon of biodiesel. To be competitive, this cost should be reduced to levels that are at or below [recent] petro diesel

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for Mobile Facilities

Science (July 11, 2010) — Chemical engineers at Purdue University have developed a new method to process agricultural waste and other biomass into biofuels, and they are proposing the creation of mobile processing plants that would rove the Midwest to produce the fuels.

“What’s important is that you can process all kinds of available biomass– wood chips, switch grass, corn stover, rice husks, wheat straw …,” said Rakesh Agrawal, the Winthrop E. Stone Distinguished Professor of Chemical Engineering.

The approach sidesteps a fundamental economic hurdle in biofuels: Transporting biomass is expensive because of its bulk volume, whereas liquid fuel from biomass is far more economical to transport, he said.

“Material like corn stover and wood chips has low energy density,” Agrawal said. “It makes more sense to process biomass into liquid fuel with a mobile platform and then take this fuel to a central refinery for further processing before using it in internal combustion engines.”

The new method, called fast-hydropyrolysis-hydrodeoxygenation, works by adding hydrogen into the biomass-processing reactor. The hydrogen for the mobile plants would be derived from natural gas or the biomass itself. However, Agrawal envisions the future use of solar power to produce the hydrogen by splitting water, making the new technology entirely renewable.

The method, which has the shortened moniker of H₂Bioil — pronounced H Two Bio Oil — has been studied extensively through modeling, and experiments are under way at Purdue to validate the concept.

Findings are detailed in a research paper appearing online in June in the journal Environmental Science & Technology. The paper was written by former chemical engineering doctoral student Navneet R. Singh, Agrawal, chemical engineering professor Fabio H. Ribeiro and W. Nicholas Delgass, the Maxine Spencer Nichols Professor of Chemical Engineering.

Agrawal, Ribeiro and Delgass are developing reactors and catalysts to experimentally demonstrate the concept. Another paper by Agrawal and Singh addressing various biofuels processes, including fast-hydropyrolysis-hydrodeoxygenation, also appeared in June in the Annual Review of Chemical and Biomolecular Engineering.

The Environmental Science & Technology paper outlines the process, showing how a portion of the biomass is used as a source of hydrogen to convert the remaining biomass to liquid fuel.

“Another major thrust of this research is to provide guidelines on the potential liquid-fuel yield from various self-contained processes and augmented processes, where part of the energy comes from non-biomass sources such as solar energy and fossil fuel such as natural gas,” said Singh, who is now a researcher working at Bayer CropScience.

The new method would produce about twice as much biofuel as current technologies when hydrogen is derived from natural gas and 1.5 times the liquid fuel when hydrogen is derived from a portion of the biomass itself.

Biomass along with hydrogen will be fed into a high-pressure reactor and subjected to extremely fast heating, rising to as hot as 500 degrees Celsius, or more than 900 degrees Fahrenheit in less than a second. The hydrogen containing gas is to be produced by “reforming” natural gas, with the hot exhaust directly fed into the biomass reactor.

“The biomass will break down into smaller molecules in the presence of hot hydrogen and suitable catalysts,” Agrawal said.”The reaction products will then be subsequently condensed into liquid oil for eventual use as fuel. The uncondensed light gases such as methane, carbon monoxide, hydrogen and carbon dioxide, are separated and recycled back to the biomass reactor and the reformer.”

Purdue has filed a patent application on the method.

The general concept of combining biomass and carbon-free hydrogen to increase the liquid fuel yield has been pioneered at Purdue. The researchers previously invented an approach called a “hybrid hydrogen-carbon process,” or H₂CAR.

Both H₂CAR and H₂Bioil use additional hydrogen to boost the liquid-fuel yield. However, H₂Bioil is more economical and mobile than H₂CAR, Singh said.

“It requires less hydrogen, making it more economical,” he said. “It is also less capital intensive than conventional processes and can be built on a smaller scale, which is one of the prerequisites for the conversion of the low-energy density biomass to liquid fuel. So H₂Bioil offers a solution for the interim time period, when crude oil prices might be higher but natural gas and biomass to supply hydrogen to the H₂Bioil process might be economically competitive.”

The research was funded by the U.S. Department of Energy, the National Science Foundation and the U.S. Air Force Office of Scientific Research, and is affiliated with the Energy Center at Purdue’s Discovery Park.

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Biological Engineers Generate

Natural Gas with Bacteria

October 1, 2006 — A new kind of waste digester uses two different strains of bacteria in different tanks. This would normally take place in the same environment, but microbiologists have now separated it into two stages that increases natural-gas production. The technology increases efficiency and can turn three tons of food scraps into enough energy to power 25 homes for a day.

DAVIS, Calif. — There’s a new twist on the old adage, one man’s trash is another man’s treasure. Now that trash may be another man’s power. Researchers in California are turning garbage into bio-gas that may one day provide the electricity in your home.

Trash could soon be powering your home. A new digester can transform it into energy. It uses two strains of bacteria to convert waste into bio-gas. Most digesters store both bacteria in the same tank, which makes the process unpredictable and slow. But not this digester.

“Zhang’s process takes the two bacteria and separates them into two separate environments,” Dave Konwinski, the director of OnSite Power Systems in Davis, Calif., tells DBIS.

This new and improved digester is the brain child of Biological Engineer Ruihong Zhang. She and her students at UC Davis first built its prototype in the lab. She’s thrilled her new technology is being put to use in the real world.

“It’s a new technology … So it’s like a child grow into adult,” she says.

The digester will turn three tons of food scraps into energy for 25 houses a day. But it’s not just for homes. The digester could be especially useful to fuel processing plants. It s scheduled to be up and running this fall. OnSite Power Systems plans to market it in several states in the next couple of years, including California, Wisconsin and Minnesota.

“We can actually scale a digester to fit their current operations, fill it right at their operations, take the waste stream into the digester, and the energy right back into the plant,” Konwinski says. “It will make a substantial dent in our current energy requirement for petroleum.”

It’s a win-win-win situation for the environment, industry and consumers.

BACKGROUND: Environmental engineers at the University of California, Davis, are building a full-scale anaerobic digester that can convert any type of solid organic waste into electricity — even leftovers from restaurants. The system is part of the $100,000 Sacramento Municipal Utility District (SMUD pilot project), but an even larger digester system is being put into place in San Francisco.

HOW IT WORKS: In the process, food waste is collected from restaurants and institutions and then fed to bacteria that thrive in low-oxygen environments. It’s called anaerobic digestion, a naturally occurring process of decomposition. One type of bacteria turns carbohydrates into simple sugars, amino acids and fatty acids. A second group of bacteria eats those compounds and turns them into hydrogen gas, carbon dioxide, and acetic acid — the primary component of vinegar. Then a third group of bacteria takes those broken-down compounds and turns them into methane and carbon dioxide. Between 60 and 80 percent becomes methane. The methane can be used as fuel for an internal combustion engine that provides electricity.

TYPES OF DIGESTION: Anaerobic digestion is not the same thing as human digestion, since the type of bacteria that produce methane don’t live in the human digestive tract. Industrial anaerobic digesters can also harness this natural process to treat waste, provide heat, and increase nutrients in soil. They are most commonly used for sewage treatment and for managing animal waste.

BENEFITS: The goal of SMUD is to obtain 20 percent of its electricity from renewable sources such as wind, solar, and biodegradable matter by 2011. Currently SMUD derives 10 percent of its electricity from renewable sources, of which biomass accounts for 2.5 percent. The UC-Davis digester would keep food and other biodegradable waste out of landfills; food leftovers account for 18 percent of a landfill’s contents. One tone of leftover food can produce enough fuel to power 18 homes for one day.

WHAT ARE EXTREMOPHILES? An extremophile is any microbe that thrives in extreme conditions, such as temperature (extreme heat or cold), pressure, salinity, low oxygen environments, or high concentrations of hostile chemicals. Most extremophiles belong to a class known as archaeobacteria, but certain species of worm, crustacean and krill can also be considered extremophiles.

The Institute of Electrical and Electronics Engineers, Inc., contributed to the information

Sourced and published by Henry Sapiecha 7th June 2010