Featured Research

from universities, journals, and other organizations

Fuel from market waste

Date:
February 9, 2012
Source:
Fraunhofer-Gesellschaft
Summary:
Mushy tomatoes, brown bananas and overripe cherries -- to date, waste from wholesale markets has ended up on the compost heap at best. In future it will be put to better use: Researchers have developed a new facility that ferments this waste to make methane, which can be used to power vehicles.

Factory making biogas out of wholesale market waste.
Credit: Copyright Fraunhofer IGB

Mushy tomatoes, brown bananas and overripe cherries -- to date, waste from wholesale markets has ended up on the compost heap at best. In future it will be put to better use: Researchers have developed a new facility that ferments this waste to make methane, which can be used to power vehicles.

Drivers who fill up with natural gas instead of gasoline or diesel spend less on fuel and are more environmentally friendly. Natural gas is kinder on the wallet, and the exhaust emissions it produces contain less carbon dioxide and almost no soot particles. As a result, more and more motorists are converting their gasoline engines to run on natural gas. But just like oil, natural gas is also a fossil fuel, and reserves are limited. Researchers at the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB in Stuttgart have now developed an alternative: They have found a way to obtain this fuel not from Earth's precious reserves of raw materials, but from fruit and vegetable waste generated by wholesale markets, university cafeterias and canteens. Fermenting this food waste produces methane, also known as biogas, which can be compressed into high-pressure cylinders and used as fuel.

In early 2012, the researchers will begin operating a pilot plant adjacent to Stuttgart's wholesale market. The facility uses various microorganisms to generate sought-after methane from the food waste in a two-stage digestion process that lasts just a few days. "The waste contains a lot of water and has a very low lignocellulose content, so it's highly suitable for rapid fermentation," says Dr.-Ing. Ursula Schließmann, head of department at the IGB. But it still presents a challenge, because its precise composition varies every day. Sometimes it has a high proportion of citrus fruits, while other times there are more cherries, plums and lettuce. On days with a higher citrus fruit content, the researchers have to adjust the pH value through substrate management, because these fruits are very acidic. "We hold the waste in several storage tanks, where a number of parameters are automatically calculated -- including the pH value. The specially designed management system determines exactly how many liters of waste from which containers should be mixed together and fed to the microorganisms," explains Schließmann. It is vital that a correct balance be maintained in the plant at all times, because the various microorganisms require constant environmental conditions to do their job.

Another advantage of the new plant lies in the fact that absolutely everything it generates can be utilized; the biogas, the liquid filtrate, and even the sludgy residue that cannot be broken down any further. A second sub-project in Reutlingen comes into its own here, involving the cultivation of algae. When the algae in question are provided with an adequate culture medium, as well as carbon dioxide and sunlight, they produce oil in their cells that can be used to power diesel engines. The filtrate water from the biogas plant in Stuttgart contains sufficient nitrogen and phosphorus to be used as a culture medium for these algae, and the reactor facility also provides the researchers with the carbon dioxide that the algae need in order to grow; while the desired methane makes up around two thirds of the biogas produced there, some 30 percent of it is carbon dioxide. With these products put to good use, all that is left of the original market waste is the sludgy fermentation residue, which is itself converted into methane by colleagues at the Paul Scherrer Institute in Switzerland and at the Karlsruhe Institute of Technology.

Others involved in this network project, which goes by the name of ETAMAX, include energy company EnBW Energie Baden-Württemberg and Daimler AG. The former uses membranes to process the biogas generated in the market-place plant, while the latter supplies a number of experimental vehicles designed to run on natural gas. The five-year project is funded to the tune of six million euros by the German Federal Ministry of Education and Research (BMBF). If all the different components mesh together as intended, it is possible that similar plants could in future spring up wherever large quantities of organic waste are to be found. Other project partners are the Fraunhofer Institute for Process Engineering and Packaging IVV in Freising, FairEnergie GmbH, Netzsch Mohnopumpen GmbH, Stulz Wasser- und Prozesstechnik GmbH, Subitec GmbH und the town Stuttgart.


Story Source:

The above story is based on materials provided by Fraunhofer-Gesellschaft. Note: Materials may be edited for content and length.


Cite This Page:

Fraunhofer-Gesellschaft. "Fuel from market waste." ScienceDaily. ScienceDaily, 9 February 2012. <www.sciencedaily.com/releases/2012/02/120209135836.htm>.
Fraunhofer-Gesellschaft. (2012, February 9). Fuel from market waste. ScienceDaily. Retrieved September 23, 2014 from www.sciencedaily.com/releases/2012/02/120209135836.htm
Fraunhofer-Gesellschaft. "Fuel from market waste." ScienceDaily. www.sciencedaily.com/releases/2012/02/120209135836.htm (accessed September 23, 2014).

Share This



More Earth & Climate News

Tuesday, September 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Hundreds of Thousands Hit NYC Streets to Protest Climate Change

Hundreds of Thousands Hit NYC Streets to Protest Climate Change

AFP (Sep. 22, 2014) — Celebrities, political leaders and the masses rallied in New York and across the globe demanding urgent action on climate change, with organizers saying 600,000 people hit the streets. Duration: 01:19 Video provided by AFP
Powered by NewsLook.com
French FM Urges 'powerful' Response to Global Warming

French FM Urges 'powerful' Response to Global Warming

AFP (Sep. 22, 2014) — French Foreign Minister Laurent Fabius on Monday warned about the potential "catastrophe" if global warming was not dealt with in a "powerful" way. Duration: 01:08 Video provided by AFP
Powered by NewsLook.com
Ongoing Drought, Fighting Put Somalia at Risk of Famine

Ongoing Drought, Fighting Put Somalia at Risk of Famine

AFP (Sep. 22, 2014) — After a year of poor rains and heavy fighting Somalia is again at risk of famine, just three years after food shortages killed 260,000 people. Duration: 01:10 Video provided by AFP
Powered by NewsLook.com
Rockefeller Oil Heirs Switching To Clean Energy

Rockefeller Oil Heirs Switching To Clean Energy

Newsy (Sep. 22, 2014) — The Rockefellers — heirs to an oil fortune that made the family name a symbol of American wealth — are switching from fossil fuels to clean energy. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins