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CALMIM (California Landfill Methane Inventory Model) is a field-validated 1-dimensional transport and oxidation model that calculates annual site-specific landfill methane emissions based on the major processes that control emissions:

The driving force for emissions is the methane concentration gradient through each cover type coupled with typical annual soil moisture and temperature variability which control methane transport and microbial methane oxidation over an annual cycle. 

The climate-related factors (meteorology and soil microclimate) are automatically accessed based on the site location and physical properties of the cover materials.   This model is intended to be user friendly with a series of input boxes where the user enters basic information on the areas and properties of daily, intermediate, and final cover materials, as well as the % surface area of each cover type with engineered gas recovery (either vertical wells or horizontal collectors).

CALMIM calculates daily emissions for each cover type which are summed to provide an annual total for the site (both in units of g methane /square meter/day and for the site as a whole). 

Taking into consideration recent literature which indicates that first order kinetic models for theoretical methane generation cannot match field measurements for landfill methane emissions, CALMIM is the first landfill methane emissions model which does not rely on a first order model for methane generation based on the mass of waste in place. 

CALMIM was developed with field validation and supporting laboratory studies during 2007-2010 under the auspices of the California Energy Commission PIER (Public Interest Energy Research) Program.  CALMIM is JAVA-based, freely available to users, and is intended to be the first step in the development of improved science-based models which have been field-validated and can be internationally applied to landfill methane emissions inclusive of seasonal methane oxidation.



The USDA-ARS makes no warranties as to the merchantability or fitness of CALMIM for any particular purpose, or any other warranties expressed or implied. Since some portions of CALMIM have been validated with only limited data sets, it should not be used to make operational management decisions. The USDA-ARS is not liable for any damages resulting from the use or misuse of CALMIM, its output and its accompanying documentation. 

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