The Bochum-based engineering firm KM GmbH für Straßenbau und Umwelttechnik has presented a scientific study in cooperation with the Institute for Soil Science at the University of Hamburg and the Öko-Institut e.V. in Darmstadt. In this study, the possibilities for recycling HMV ash from the Hanseatische Schlackenkontor in road construction and earthworks are investigated, taking into account construction and environmental aspects. The result is very positive. The Hamburg situation is described as “exemplary” and “groundbreaking for the whole of Germany”.
The study first points out that incineration is an important recycling route for waste in Germany. The importance of thermal waste treatment as a recycling route for waste increased with the entry into force of the most important requirement of the Waste Disposal Ordinance, namely the final ban on the disposal of untreated municipal waste in landfills since 1 June 2005. Finally, the implementation of the “Concept 2020” of the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU) is expected to lead to a further increase in interest in waste incineration, as according to this concept, pre-treated municipal waste will no longer be landfilled in the future.
Therefore, the study comes to the general conclusion that “HMV ash from waste incineration will play an increasingly important role in the future”. It also states: “Germany will increasingly be called upon, not only in terms of recycling management, but also as a result of European constraints, to continue to deal intensively with the recycling of HMV ash, especially in view of the expected future – higher – quantities of HMV ash”.
With regard to the properties of HMV ash, the authors are of the opinion that “ash is a secondary building material which has already undergone extensive testing. This applies both to the structural properties and to the environmental compatibility”.
For Hamburg, the study emphasises that the MVB and MVR waste incineration plants, in particular, achieve a significant reduction in the mobilisation of chlorides from the HMV ashes by means of integrated slag washing. In addition the treatment technology exhibits a high standard, so that structural engineering and also from view of the environmental compatibility the reservations on the part of the users should be eliminated.
The authors describe the overall situation in Hamburg as “exemplary”: “In addition to the above-average quality of the ashes, their quality is checked by means of elaborate and well-functioning quality monitoring. In addition, intensive coordination between all the authorities involved in the project in the City of Hamburg ensures that the ashes (= HMV ash, editor’s note) are only used in construction measures that are suitable for this purpose.
It is also emphasized that Hamburg, in comparison to other federal states, has for many years kept an installation register with the recording of all relevant characteristic values. “Furthermore, the Hanseatische Schlackenkontor undertakes to take back the HMV ash in the event of a possible dismantling (take-back obligation)”.
Dr. Joachim Greinert, CEO of Hanseatisches Schlackenkontor GmbH: “The installation register and the take-back obligation have proven themselves as confidence-building measures. Last but not least, our demanding quality standards have resulted in a very high recycling rate for HMV ash in Hamburg compared to the federal average. We will continue to do everything we can in the future to meet these standards and improve them further”.
In Hamburg, HMV ash is marketed under the name “emvau-schlacke“. The main areas of application are construction types beneath water-impermeable surface layers (mainly asphalt in road construction, concrete in commercial/industrial areas) but also under partially permeable surface layers (pavement / slabs).
The 25-page study and the preface are available here.