The sustainable landfill bioreactor - A flexible approach to solid waste management

According to the EC environmental policies, the disposal of municipal solid waste to landfill is the method of last resort European legislation requires both that solid waste be diverted away from landfills and that improved environmental controls on landfilling are implemented. In particular, the Landfill Directive of 1999 requires strict control of landfill management practices, including a sharp reduction in the proportion of biodegradable waste disposed to landfill. Currently landfilling is still the most widely used disposal route in Europe and it will continue to be an important waste management option for many years to come, particularly in the states of the former Eastern Bloc, even though rising environmental standards will cause landfill disposal costs to rise. Given this reality, a multi-disciplinary approach to landfill management involving geochemists, geotechnical engineers, civil engineers and microbiologists, has lead to a rapid development of the concept of landfilling as a sustainable technology. The traditional model of a landfill as a permanent waste deposit in which decomposition processes are minimised has given way to the concept of a controlled decomposition process managed as a large-scale bioreactor. The fundamental aim of the sustainable landfill is to optimise the natural degradation processes in the waste and to contain the products of degradation to prevent pollution of the environment. This controlled bioreactor landfill is seen as a flexible, cost-effective, and sustainable approach to current waste disposal problems, particularly when combined with material recovery either before or after the biological treatment step. Indeed, it may no longer be necessary to view landfilling as a disposal system at all, but rather as a method of large-scale processing of waste to be combined with recovery and recycling processes. This paper discusses both the legal and technical aspects driving the development of the sustainable targe-scale bioreactor concept of landfilling.