Long-term behavior of passively aerated compost methanotrophic biofilter columns.
The methane oxidation potential of several types of compost methanotrophic biofilter columns were compared in the laboratory over a period of 220 days. The results indicate an increase in methanotrophic activity over a period of about 100 days, up to a maximum of 400 g m(-2) day(-1), and a gradual decline to about 100 g m(-2) day(-1) within the next 120 days. High methane oxidation rates appear to be restricted to a small area of the column, 10-15 cm thick. Based on the laboratory investigations carried out to determine the cause for the decline in methane oxidation rate, it was concluded that the formation of exopolymeric substances (EPS), at the zones of maximum methane oxidation, was responsible for this decline. In monitoring methane oxidation in a column for up to 600 days, it was observed that mixing of the medium after formation of EPS enabled the column to temporarily recover high performance. The results suggest that stable, homogenous compost, with a low C/N and low ammonium content, mixed on a regular basis, could achieve and maintain high methane oxidation efficiencies.
Department of Civil Engineering, University of Calgary, 2500 University Drive N.W., Calgary, Alta., Canada T2N 1N4.
J H
JH
Wilshusen
J P A
JP
Hettiaratchi
V B
VB
Stein
D000397:Air Pollution / Q000517:prevention & control; D001419:Bacteria; D001673:Biodegradation, Environmental; D005285:Fermentation; D005374:Filtration; D017752:Greenhouse Effect; D008697:Methane / Q000737:chemistry*; D010084:Oxidation-Reduction; D012037:Refuse Disposal
D008697:Methane