ECN publication
Methaanemissie van de deponie Nauerna : november 1999
Published by: Publication date:
ECN 1-4-2000
ECN report number: Document type:
ECN-C--00-056 ECN publication
Number of pages: Full text:
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Methane concentrations in plumes resulting from emissions from a landfillat Nauerna, west of Amsterdam, Netherlands, were measured in November 1999. This was the third experiment of its kind at the Nauerna landfill. The total methane emission of the landfill was estimated using measurements of the methane concentration in the plume downwind of the landfill. These measurements were performed using a tunable diode laser, mounted in a van. A set of 10 plume measurements was obtained. The emission was estimated by fitting the calculated methane concentrations obtained with a gaussian plume model with the actually observed concentrations along the measurement path. The emission estimated from the plume measurements at Nauerna amounted to 109 #+# 33 g CH4 s"-"1. This is equivalent to an annual emission level of 3.4 kton CH4/y. The standard deviation of the 10 different estimates is significantly larger compared to the levels obtained in 1997 and 1998. This is due to the fact that the measurement path had to be changed. Part of the measurement path used in the last two years could not be used anymore because of the development of a new harbour. As a result, a part of the measurement path is not perpendicular but parallel to the plume axis. Variations in wind direction have a more pronounced effect on the concentrations on this part of the path which caused the variation in the subsequent emission estimates. The emission levels in 1999 were significantly higher than obtained in 1997 and 1998. Also the main source area on the landfill changed from the south east to the middle on the south side compared to the previous years. There are three possible reasons that can explain the high emission level : (1) The fresh waste that is deposited on the landfill shows a relatively high emission; (2) The air pressure showed a minimum of 1000 mbar the day before measurements. This might have lead to enhanced venting of the landfill; and (3) The average temperature was only 2C (compared to about 8-9C during the campaigns in 1997 and 1998). Low temperatures inhibit methane oxidation activity in the topsoil of the landfill. 9 refs.

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