Food waste can be more than just garbage

It happens to everybody at some time: you lose track of a yoghurt hidden away at the back of your fridge, mold starts to grow on a loaf of bread in your cupboard, and somehow you wind up cooking too much food again. According to information from the United Nations’ Food and Agriculture Organization (FAO), a third of all food produced worldwide ends up in the garbage. In a study for Germany, the University of Stuttgart found that every year domestic homes throw away just under seven million metric tons of food – primarily fruit and vegetables, but also baked goods, leftovers from meals, and dairy products. This waste of food also has a highly detrimental impact on the environment. For example, you need around 1,000 liters of water to produce a kilogram of bread, while it takes around 5,000 liters to make the same amount of cheese. And that is not to mention the energy consumed by food processing companies or the emissions generated during production. Last year, for instance, the FAO revealed that three billion metric tons of environmentally harmful gases are emitted every year as a consequence of food waste. These are figures that are prompting not only consumers but also industry and research to think again. An established technology for processing unavoidable food waste is to use it in biogas plants for generating energy. But that is only one possibility …

Another problem that is exercising governments, industry, business, and the research sector throughout Europe and presenting them with new challenges is the increasing scarcity of resources. There has been a massive swing toward the saving of energy and consequently toward the increased use of renewable energy. New EU laws and regulations confirm this trend. Industry and research are taking a growing interest in innovative technologies for replacing precious non-renewable raw materials and similar purposes. This is where the EU’s »PlasCarb« project comes in, which counts the Fraunhofer Institute for Building Physics IBP among its partners. Headed by the UK-based Centre for Process Innovation (CPI), »PlasCarb« is designed to run for three years and is funded by the European Commission’s Seventh Framework Programme for Research (FP7). The goal of the project is to obtain graphitic carbon (C) and hydrogen (H2) from mixed food waste. The former is one of the 14 critical raw materials identified by the EU. One part of the consortium’s work is concerned with the technological processes for obtaining the two materials, while in another part Fraunhofer IBP’s Life Cycle Engineering Department tests and evaluates the environmental and economic sustainability of the processes using life cycle assessment (LCA) and life cycle costing (LCC) techniques. »Building on the standardized life cycle assessment and its results, the LCC method gives us the ability to analyze commercial aspects under identical system boundaries and boundary conditions,« says Christian Peter Brandstetter, a scientist in the Materials and Product Systems working group at Fraunhofer IBP’s Life Cycle Engineering Department, explaining his role in the »PlasCarb« project.

PlasCarb as technical innovation and sustainable business model for future markets?
The technology in »PlasCarb« is based on the anaerobic digestion of food waste such as is used in today’s biogas plants. The resulting biogas consists primarily of methane (40-75 percent) and carbon dioxide (25-55 percent) and also of water (0-10 percent), nitrogen (0-5 percent), and oxygen (0-2 percent), as well as small amounts (0-1 percent) of hydrogen, hydrogen sulfide, and ammonia. Consequently, the biogas must be cleaned for subsequent technical applications in order to remove impurities from the methane so that it can be separated into high-value graphitic carbon and hydrogen using an innovative low-temperature microwave plasma technique. The project plans to generate 25,000 cubic meters of biogas within a month through the anaerobic digestion of 150 metric tons of food waste and to obtain high-quality graphitic carbon and hydrogen from a portion of around 2,400 cubic meters of this biogas.
So that »PlasCarb« does not remain just a technologically innovative project, but one that could also be capable of persuading the new markets of the process’s ecological benefit and cost effectiveness, Brandstetter and his colleagues are working to analyze that process. After all, the bottom line for industry is inevitably whether the environmental and financial gain from obtaining these valuable raw materials justifies the cost of setting up and operating the plants. Carbon is of huge importance – particularly for the lightweight construction sector. Interest in the material is especially keen in the automotive and aerospace industries, because it is lightweight like aluminum yet hard like steel. The resulting weight savings make significant reductions in fuel consumption during use and therefore all global warming relevant emissions as par example CO2 emissions possible – although the exact choice of application is no simple matter, as Fraunhofer IBP demonstrated in its study »Environmental aspects of lightweight construction in mobility and manufacturing«. You have to look on the whole cycle. Hydrogen is storable and has a variety of applications using ordinary infrastructure. It can be used either as a material or for mobility purposes and power generation. These are all good reasons to work on obtaining these substances. »In parallel with the other activities, we will be analyzing whether the project represents a sustainable food waste management model for Europe that permits optimum technical implementation,« says Brandstetter.

Life cycle assessment and life cycle costing methods
Life cycle assessment permits systematic analysis of the environmental impacts of products, processes, or services over their whole life cycle. It incorporates all environmental influences during production, usage, and disposal as well as all associated upstream and downstream processes. »The holistic LCA approach also goes by the name of cradle-to-grave analysis,« adds Brandstetter. LCA is part of life cycle engineering and is standardized in ISO 14040 ff, which sets out four consecutive phases for scientists to follow. First, the project’s goal and scope definition of the analysis are defined as precisely as possible (phase 1). This includes defining the system and its boundaries – in other words, the object of the analysis – as well as determining the frame and data quality requirements to be worked with. The subsequent Life Cycle Inventory Analysis (phase 2) contains the recording and quantification of all inward and outward material and energy flows. Using these quantified inputs and outputs, the Life Cycle Impact Assessment (phase 3) employs suitable characterization models that calculate the potential environmental impacts and the influence on human health and the availability of resources with the aid of special software. Finally, the results of the inventory analysis and the impact assessment are interpreted against the objectives of the life cycle assessment set out at the beginning (phase 4).
»However, sustainable activity doesn’t end with taking environmental aspects into account,« clarifies Brandstetter. The commercial aspect of process and product development also plays a key role.  »To make very innovative ideas more attractive to markets – always a particular challenge – life cycle costing (LCC) is a valuable tool and a good means of supporting sustainable decision-making.« The life cycle for LCC should be defined analogously to the analysis framework for the life cycle assessment. During an LCC analysis, Fraunhofer IBP scientists work out the entire life cycle costs of a product or service. This allows cost drivers in the process to be isolated and evaluated and also compared and optimized if required. Using the LCC method in parallel to the emerging project, investment and operating costs can be estimated even at a very early stage in product development – and of course these costs are a very important factor when deciding for or against a product.
Brandstetter and his project partners appreciate the huge potential this project holds, and working with food waste to create a cleaner environment is a powerful motivation for them to develop innovative technologies and explore new avenues. (taf)