Landfillmining Zuienkerke

Enhanced Landfill mining & management (ELFM²) as a concept focuses on the valorisation of materials and energy out of landfills. The valorization must be as sustainable as possible, having a high recycling rate and high energetic profitability when incineration is applied. Thanks to Flanders’ optimal separated waste collection, it is possible to make the best suitable choices with these criteria in mind.

Since 2012, OVAM experiments with different waste separation techniques or combinations of these techniques to improve output. Separation was investigated during projects on landfills in Hasselt (Limburg province) and Evergem (East Flanders province).

Sieving installation and windshifter on the closed Zuienkerke landfill

Taking this idea to the next level, OVAM created a special assignment for this Enhanced Landfill Mining concept to test on a third site in Zuienkerke (West Flanders province) in which the innovative separation techniques were linked to different waste streams when applied on excavated landfills, thus determining the yield of each type of waste. Five companies participated in the project.

Meanwhile, OVAM launched a second assignment specifying the technical and economic proceedings of the applied separation techniques. The core of this second assignment can be summarized into five questions:

  • Which fraction is obtained with which separation technique and how much?
  • The purity of each fraction?
  • What are the possibilities in terms of valorization?
  • What is the degree of mobility for the applied technologies (s.h. how easy are the machines translocated)?
  • What is the overall profitability?

Each contractor had access to one hundred tonnes of frenchly excavated municipal solid waste. The material was primarily deposited during the sixties. The contractors separated the waste with the only goal being a maximum recuperation of materials and/or energy. Combinations of separation techniques included: sieving, belt magnets, hydrocyclones, belt press, windshifting, eddy current separator, optical separation, aqua motor and ballistic separation. Based on this test, OVAM showed that a great amount of waste can be recuperated as waste-to-materials and only a small part as waste-to-energy. Additionally, efforts were made on-site to separate the different sorts of plastic waste by combining different sieving methods and windshifting.

Based on the results of the Zuienkerke project and the feedback of the contractors, new propositions were made for further innovative research on waste separation.      

Sieving installation and windshifter on the closed Zuienkerke landfill
Remediation Terracotta first LFM project in 1998

The landfill mining project of OVAM occurred before the concept of ELFM and DLM existed. On site of a landfill containing household and industrial waste, a recycling and processing plant was built where the inert materials were recycled. In this way significant reductions in landfill costs and related environmental taxes were realised. The cleaned and recycled materials found a beneficial reuse. The residual fraction was redeposited at a landfill site close by.

OVAM's ELFM program

Enhanced Landfill Mining (ELFM) was a strategic project by OVAM that ran from 2011 to 2015. It was at that time a brand new concept developed by the ELFM consortium in Flanders, of which OVAM is a member.

The concept of Enhanced Landfill Mining (ELFM) was introduced and defined by Jones et al. as:

“the safe conditioning, excavation and integrated valorisation of landfilled waste streams as both materials and energy, using innovative transformation technologies and respecting the most stringent social and ecological criteria”.

All departments at OVAM are involved, because ELFM covers the waste, materials and soil policy areas. An ELFM project team defined this ELFM concept in more formal terms.

At the same time OVAM developed a strategy in which its main lines were the inventory, valorisation, communication and legal framework. Based on this information and knowledge, ELFM was seen as a form of sustainable stock management.

During the planning period, OVAM set up various subprojects to collect specific data about the research areas. This involved both its own databases and the support of third parties. From this point of view, landfills were no longer considered as a final and static situation but as a dynamic part of the materials cycle. The potential valorisation of the disposed waste is an important aspect in the assessment of the environmental impact of landfills.

Project implementation

Within OVAM a project structure was set up in which the three departments are represented and take on specific tasks. It is controlled by the board of directors. For each segment (surveying, mapping, mining) practical examples were sought and implemented. This approach supported a firm basis for the ELFM policy and adjusted it where necessary. Every subtask needed to contribute to the final goal, i.e. the ISO 2015 certification, the standard for stock management at landfill sites. The general principles of a project-based approach were defined into 15 subtasks with milestones, in the period 2012-2015.

Knowledge gathering

ELFM is not only a relatively new concept but is also still little explored and elaborated. In international terms, too, knowledge is limited and, as a result, OVAM has defined a concrete research programme. The ELFM concept is described as a form of stock management, and this management has 3 pillars: an inventory of the landfill sites, a description of the landfill sites and the mining of landfill sites. For every pillar research projects are set up and supported. Because only fragmented knowledge is present, OVAM is systematically looking for partners and opportunities to improve knowledge gathering. This explains the attention for scaling up the ELFM consortium to EU level and frequent English communication around this topic.