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. However, 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 the 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.
So how many kilometres are you getting to the tomato?
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. However, 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 litres 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 used; 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% 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.
This plant in Stuttgart makes biogas out of waste from wholesale markets. (Image: Fraunhofer IGB)
Tailor-made search tools for the web
For companies, customer feedback is a matter of strategic importance. Smart apps for the semantic analysis of user opinions from the web help businesses keep an eye on feedback. Users benefit as well: With the „Eat and Drink’ app, the user can quickly learn all about the special features of restaurants, cafes and bars.
Does my city have a nice, quiet beer garden with a grill? Which restaurant has spicy Asian cuisine on its menu, and which cafe dreamily delicious cakes? Who offers the quickest service for a tasty lunch? Nowadays, anyone turning to the Internet in search of the special features of the local restaurant scene can choose between a host of online reviews or starred listings in portals for general categories such as value for the money, food and service. What is often lacking, though, is the reasoning behind the good or bad review. A new, intelligent smartphone app now provides details about restaurants, bars and cafes: ‘Eat and Drink’ analyses more than 200 000 reviews from throughout the Internet, condensing opinions, bundling information, gleaning specific features from the sources and providing restaurant recommendations.
At a glance, the user can see whether or not the atmosphere is welcoming, the clientele is young, or the background music is a source of annoyance. ‘Our intelligent app makes the user‘s job easier. There‘s no need to read through lengthy restaurant reviews, instead the app provides a summary of the special features and main aspects of a particular establishment. ‘Eat and Drink‘ provides information as to why a particular rating is positive or negative,’ Dr. Melanie Knapp of the Fraunhofer Institute Intelligent Analysis and Information Systems IAIS notes. ‘The user simply launches an area or keyword search. The result is displayed in the form of tags.’
With ‘Eat and Drink,’ Knapp and her team have created an app that semantically analyses and processes unstructured text. In contrast to keyword or rule-based processes like those used by well known online search engines, this solution uses learning and pattern-recognising methods to deliver results that are much more refined and far less cut-out in nature. The researchers call their intelligent search methods ‘Smart Semantics’. This approach enables machine-driven classification of complex websites and detailed analysis of text, even at the sentence level. The method studies syntax, individual words, verbs, pronouns and nouns.
The underlying technologies on which the app is based were developed by IAIS scientists in the THESEUS research program (www.theseus-programm.de/en/index.php). ‘Customer opinions can be optimally evaluated using our search technology. It can be flexibly adapted for use with all kinds of topics and text. Apps and programs could also be developed for entirely different sectors, such as consumer goods or the automobile industry. ‚Eat and Drink‘ is just one example of how technologies generated under the THESEUS program can be practically applied in the B2C and B2B areas,’ Knapp explains.
Just what such a B2B application might look like is demonstrated by the experts in the form of ‘Quote’ – a semantic search engine for quotations. This application has been trained to hunt down quotations by public figures found in online premium news providers. Angela Merkel, Magdalena Neuner or Till Schweiger are just some of the VIPs whose statements can be called up using the app. Users can also search for quotes on specific topics, such as Greece or the euro – ‘Quote’ returns current quotations found on the content of interest. The app also generates a fact file on each person. The file provides a list of the topics on which the person in question has been quoted in recent months. ‘Press offices are not the only ones interested in ‘Quote‘. Politicians and managers in the public eye can also use the search engine as a research tool, or to analyse the competition,’ Knapp is convinced.
Customers‘ and users‘ online opinions can be optimally evaluated using search technologies developed by Fraunhofer IAIS. (Image: Fraunhofer IAIS)