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The Road to MBT Technology
| | An extraordinary increase of the waste volume in the 1980s and detectable environmental damages caused from the storage of not pre-treated urban wastes, as well as polluted leachate and the greenhouse-effective methane gas emissions led for search of better disposal concepts. Waste experts recognised - besides the requirement for a more intensified waste recovery - the need for pre-treatment of the waste prior to the storage in landfills.
By Thomas Grundmann, Chairman, and Michael Balhar, Branch Manager of the German ASA e. V. Arbeitsgemeinschaft Stoffspezifische Abfallbehandlung
In 1993 the Federal Council of Germany stipulated in the Technical Instructions for Urban Waste (TASi) the pre-treatment for biologically degradable wastes with waste incineration as the only accepted alternative option. The TASi granted the public waste disposal authorities a transitional period of 12 years to reorganise and restructure their plants.
The political stipulation on waste incineration plants as the only technology was among experts at that time contradictorily discussed and often couldn't be realised and get a majority in the municipalities. The public opinion showed resistance against waste incineration plants because of expectations of air pollutions (e.g. dioxins, heavy metals). A great many planning projects for waste incineration plants failed and country-wide planning projects and search for sites were withdrawn.
Foto: Archiv
The transitional situation delayed the planning of waste management companies
A transition period of 12 years seemed to be generously calculated, on account of external circumstances yet only little usage was made for real planning efforts and for the construction of new treatment capacities. One reason for that was that the planning happened during a period of reorganisation of the municipal waste management sector in Germany where serious chances of the waste management frame conditions happened.
Not before the eighties and in the beginnings of nineties the public waste disposal authorities planned, realised and financed new landfill capacities in a considerable quantity after having been pressured by the Federal States and the competent authorities to fulfil their tasks for a sufficient disposal capacity and safety.
Following the enforcement of the Packaging Ordinance and the establishing of the Dual Waste Collection System (“DSD”/Green dot) in the beginnings of nineties, in 1996 the Closed Loop and Waste Management Act (“KrW-/AbfG”) was enacted. This realigned waste management towards to closed loop management and producers responsibility; in addition parts of the waste management have been liberalised.
All these new developments caused public law disposal contractors to become uncertain about their future tasks and about the quantity of the future waste amounts to be disposed of. Not appropriate waste forecasts would have led to over capacities or disposal bottlenecks. This was underlined by heavy political discussions about the suitable method of pre-treatment and partly compelling reports and developments of new treatment technologies (e.g. pyrolysis, smouldingcombustion-process, thermoselect process) which later proved to be not suitable in practice.
Attempt for alternatives to Waste Incineration in States and Municipalities
Despite of the stipulation on waste incineration in the TASi, an administrative instruction having not been legally binding as statutory order, in some states and municipalities attempt to look for alternatives to incineration. This focuses in the question whether also mechanically-biologically pre-treated materials could be stored in an environmentally friendly manner and would this be an alternative to incineration.
The Mechanical Biological waste Treatment (MBT) technology is based on the idea that in the first instance waste has to be source separated, than recyclables and disturbing impurities selected and finally the biodegradable residues have to biologically treated with defined processes (composting/digestion) - ranging from open landfills to completely encapsulated systems with exhaust air treatment.
Lower Saxony initiated the development already before the TASi instructions had been legalised. The State of Lower Saxony supported research work for the fundamentals of the MBT technology already as of 1989/90 and later three large-scale demonstration plants with different technological concepts under scientific guidance. These plants realised a new, technically higher-level standard of the MBT accompanied by heavy criticism from the representatives of the low-tech technologies like decomposition piles, a system using chimney aeration effects etc.
In 1998 the State North Rhine-Westphalia issued a MBT guideline as legal adviser for their competent authorities with the help of which MBT could and was built instead of waste incineration plants by means of demonstration of the evidence of equivalence of the performance. At these times the State of Brandenburg increasingly introduced the MBT technology.
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