Landfilling

Development of a bio-filter process for the breakdown of methane, malodorous substances and trace gases created by active landfill gas extraction

It was demonstrated that effective oxidation of methane in bio-filters is feasible using technical active gas extraction systems. During this process, other organic trace gas components were also co-metabolically broken down and the malodorous substances in the landfill gas were effectively reduced.

 

Summary

At German landfill sites, bio-filters have to date mainly been used to eliminate smells and break down organic pollutants. Methane oxidation is a new technical area of application for bio-filtration and could in future be used at old landfills to reduce methane emissions that are harmful to the climate. 

In this sub-assignment, which is part of a joint project, bio-filters were used at the Drage landfill site in the Harburg region. Percolation was achieved by technical gas transport with pumps or fans. The gas to be treated was mixed with air before entering the bio-filters. This ensured that the entire bio-filter volume contained sufficient oxygen for microbial methane oxidation. 

Tests on a pilot-plant and container scale provided operating experience and reliable dimensioning data for large-scale implementation of the method. 

Results: 

  • The optimum filter material was found to be a mixture of compost, peat and wood fibre. It showed stable degradation rates. 
  • The bio-filter volume required for a flow equivalent to the lower limit for operating a flare (50 m³/h raw gas with a content of 20% methane by volume and a plant efficiency of 90%) was determined to be 800 m³. 
  • Several tensiometers should be used to achieve an even distribution of humidity. 
  • The system can be built as a closed design. It is particularly suitable when little space is available. 

More Project Informations

Project title:  Microbial reduction of methane emissions: development of a bio-filter process for the breakdown of methane, malodorous substances and trace gases created by active landfill gas extraction (Part 1)

Project number:  0330252

Project period:  1999 - 2003

Project region:  Germany (Hamburg)

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Source: German National Library of Science and Technology Hannover (TIB)