Komptech: Ready for new challenges

At the Institute of Waste and Recycling Management – ABF-BOKU for short – a motivated team headed by Professor Marion Huber-Humer teaches and researches innovative concepts and processes for sustainable waste and recycling management.

Climate change, scarcity of resources, food security: the questions of the future need answers. With more than 10,000 students, the University of Natural Resources and Applied Life Sciences Vienna (BOKU) is an important educational institution that provides the necessary tools for dealing with the diverse tasks and future global challenges.

Opportunity: Professor Huber-Humer, what are the competences of your institute?

Professor Marion Huber-Humer: According to the EU Waste Directive, the areas of waste prevention and reuse have the highest priority. They are important research foci at our institute. In particular, we focus on the question: How can we reduce food waste? This is one of our heartfelt topics. Circular waste management is another important area of work. Here we deal with the analysis and optimisation of collection systems and recycling options. In addition, landfilling is still an indispensable element of waste management. Therefore, we participate in the research and development of technologies for low-emission, environmentally sound landfilling of residues and residual materials and their monitoring. We measure with innovative methods and develop them further. To give an example: With open-path laser measurement devices and dispersion modelling, we conduct research to quantify greenhouse-relevant methane emissions from waste treatment plants and landfills.

Opportunity: Let’s stay with the topic of food for a moment: Current crises are leading to a disruption of supply chains, sharply rising prices are doing the rest to bring food back into the public’s focus. Is the topic of waste really relevant?

Professor Marion Huber-Humer: The impact of this waste on the climate and nature is enormous and also unnecessary. You know, food waste has been an important research area at our institute for almost twenty years and our results show that we need solutions especially for private households. Much more food is wasted at the household level than at any other stage of the value chain. Therefore, we see our task primarily in pointing out solutions – in addition to method development and comprehensive data collection. We develop very concrete guidelines for action for production, trade and consumers. Raising awareness plays a special role for the latter. That is why we also work intensively with schools and training centres in the tourism sector and participate in various practice-relevant projects.

Opportunity: Thank you very much, Professor Huber-Humer. To follow up on that, a question for her colleague, graduate engineer Erwin Binner. Mr Binner, even when acting responsibly, food waste is produced. They can be reused as biowaste, e.g. through composting. You have contributed significantly to the fact that the Austrian composting industry has a very good reputation today. Where do you see the cornerstones of the last few years?

Erwin Binner: As in many other countries, waste composting started in Austria a few decades ago. But very quickly it became clear that waste composts can contain high levels of pollutants. Therefore, in the late 1980s, quality criteria for waste composts were defined for the first time in ÖNORM S2022. At the same time, standards for testing methods and application guidelines were developed. In order to further improve the quality of composts, tests were carried out on the separate collection of biowaste from households. This was the case, for example, in Klosterneuburg, Graz and Vienna.

The first major progress was then made in 1992 with the ordinance on the “Separate Collection of Biogenic Waste”. It made waste separation obligatory as of 1995. Almost at the same time, in 1993, Ö-NORM S2200 was completed, which defined “quality criteria for composts from biogenic waste”. Together with accompanying standards, it defined significantly stricter limits than its predecessor, ÖNORM S2022.

The Austrian Compost Ordinance in 2001 was a next milestone: Austria was thus the first country in Europe to have an “end-of-waste ordinance”. If compost is produced according to this ordinance, it loses its waste character with the declaration and has product status! The ordinance largely adopted the testing parameters of S2200 and the testing methods of S2023, and the limit values – where necessary – were adjusted accordingly. Since then, we have been producing compost products of quality class A+ for use in organic farming and quality class A for use in conventional farming in Austria. We at ABF-BOKU have accompanied these processes scientifically. Above all, methods were developed here to map the quality and positive properties of composts. These include, for example, the maturity or stability of the organic compost substance. In addition, a model was developed here with which the humic substance content of composts can be determined. The humic substance content is an important quality characteristic for composts and is measured here based on an infrared spectroscopy method. Another highly topical area of research for us is microplastic contamination in composts.

Opportunity: Indeed, a pressing issue. What problems need to be solved here?

Erwin Binner: Residual waste analyses show that despite the Bio-Waste Ordinance – which has stipulated the separate collection of biogenic waste in Austria since 1995 – considerable amounts of recyclable bio-waste end up in the residual waste bin. It must be our goal to generate this for recycling in the future. This also includes accompanying measures to improve the quality of the collected biogenic waste.

Many composting plant operators complain about high levels of contaminants in the biowaste they receive. They have to remove the contaminants and this drives up their costs. To improve their situation, we need measures that start with the collection system. It is conceivable to encourage consumers to separate waste strictly through public relations work, or to use a contaminant scanner, or perhaps to distribute a kind of “red card” if someone does not adhere to the guidelines. Among other things, this is taken into account by the “Compost Ordinance NEW”. whose draft is expected soon. For the first time, the ordinance will define limits for contaminants in the delivered waste. Two percent by mass in relation to the wet mass are being discussed. Plant operators are to be allowed to accept collected waste with an impurity content of up to five percent by mass if technical measures are taken in advance to ensure that the incoming rotting material is below the two-percent value.

Opportunity: You have just returned from a congress in Lima. What challenges in waste management do emerging countries like Peru face? Is it possible to transfer our experience?

Erwin Binner: BOKU signed a partnership agreement with the Universidad Nacional Agraria La Molina back in 1990. This agricultural university has similar research areas as BOKU. Together we developed training programmes, seminars and congresses. In spring, for example, an international composting course took place, and a few weeks ago the seminar “Prevention, Recycling, Treatment and Landfilling of Waste”. There, 190 participants from South and Central America and Mexico exchanged their research results.

I consider such events and the open exchange of ideas extremely important. Only in this way can those responsible assess the advantages and disadvantages of the approach in Europe, develop adapted techniques for their own countries and, above all, learn from our mistakes. The good news is that the first successes can be seen. For example, the number of so-called “sanitary landfills” in Peru has increased in recent years. These are landfills that have a certain technical standard and a corresponding barrier effect. Emissions thus do not escape completely uncontrolled as before. Composting has been recognised as essential for agriculture as well as for waste management. Many municipalities and agricultural enterprises maintain composting plants – similar to the small-scale structure in Austria. There are already isolated approaches to the separate collection of recycling fractions and biogenic waste.

Opportunity: Professor Huber-Humer, you mentioned circular waste management at the beginning. Europe is doing its homework, even if a lot still needs to be done. But how can suitable solutions for this also be found in less prosperous countries?

Professor Marion Huber-Humer: In my view, interdisciplinary research and international cooperation between a wide range of stakeholders are key factors in advancing global waste management towards a circular economy. At our institute we work on these issues by systematically looking at material flows and processes. In doing so, we always try to consider and evaluate the entire life cycle.

Here, too, we follow the waste management premises from prevention, collection and recycling to the lowest possible emission and environmentally neutral disposal. From this, adapted procedures and technologies as well as optimised systems in this respect can be designed for countries where less money is available for waste management. For a country, one often starts with smaller, manageable projects in order to gain initial experience. These pilot projects can be scaled up step by step. It is important to recognise the local structures already in place in each country and to involve them at an early stage. These can be active, committed people on the ground – the so-called informal sector, which already takes care of the collection and recycling of certain waste streams. Or it can be existing formal organisations and educational institutions up to universities that offer waste management education and training programmes.

Opportunity: Can you give us an example?

Professor Marion Huber-Humer: I’d be happy to give you several, because we have carried out many very different projects in recent years. We have always found that knowledge transfer and training are essential aspects. A good example is a Tempus project, funded by the OeAD, the Austrian Agency for Education and Internationalisation. There, we developed waste management study programmes together with students and colleagues from the Technical University of Dresden and universities from Ukraine and Belarus. In the course of this, regional waste management plans were developed in cooperation with student groups and local stakeholders.

In another project, we worked with partners in Ethiopia to implement separate collection of organic waste in a district of the capital Addis Ababa. This waste was then composted in a decentralised plant and the end product was a locally available fertiliser. We are currently involved in several projects to deal with waste electrical equipment in the Caribbean and Laos. The insularity of the small Caribbean countries, for example, is a specific regional challenge. Other project examples in recent years include ship recycling and the handling of hazardous waste types in China and the treatment of plastic waste in Vietnam. With regard to the modernisation of the municipal waste management system, we were active in Kazakhstan and Russia. There, the main focus was on monitoring landfills as well as measures and technologies to minimise emissions.

Opportunity: In many countries, mixed household waste is the largest fraction in terms of volume. Can its mechanical-biological treatment be a contribution to sustainable waste management?

Professor Marion Huber-Humer: Yes, definitely. In many of the foreign projects just mentioned, we have experienced that rapid implementation of technologies that are as simple and robust as possible already significantly improves the environmental situation. The mechanical-biological treatment of municipal waste is suitable for economically weak countries as a “low-tech” measure. It functions there as a kind of bridging technology, as was the case in Austria twenty or thirty years ago. At that time there were not enough thermal treatment capacities here.

In the mechanical stage, recyclable materials such as metals or thermally usable fractions can be obtained. If necessary, they can be used as substitutes for primary energy sources in industrial plants in the region. But the major benefit for the environment lies above all in the significant reduction of greenhouse-relevant methane emissions: If mixed household waste is mechanically-biologically processed before it is landfilled, the remaining waste organic matter stabilises and is no longer as easily degradable. If this stabilised material ends up uncompacted in a landfill, it also promotes the process of biological methane oxidation. This means that methane, which is produced and emitted in the deeper landfill areas with untreated waste, can be degraded by methane-oxidising microorganisms. These organisms preferentially settle in the pre-treated material and convert the methane into water and carbon dioxide. And carbon dioxide has a much lower greenhouse effect compared to methane. The result is thus a multiple win for the environment in countries where currently, due to often lacking legal and weak institutional as well as economic framework conditions, largely uncontrolled landfilling is still the primary waste treatment route.

For more information, please visit: