Aprovechamiento de la composta para la oxidación de metano

Abstract

Methane is a greenhouse gas and wastes are among its main anthropogenic sources. Methane biological oxidation is a mechanism through natural systems and soils, especially those with high organic content, eliminate this gas. Mature compost can be a suitable substrate for methanotrophs, the micro organisms responsible of methane oxidation in soils; therefore, compost can be used as a cover layer in solid waste disposal sites in order to avoid methane emissions. The aim of this work was to analyze the methane oxidation capacity of composts obtained from common organic wastes in Yucatan. Nine PVC columns were designed and constructed with a diameter of 20 cm and height of 90 cm. Groups of 3 columns were filled with different composts (municipal solid waste 1 and 2 -RM1, RM2- and green waste). Each group had 3 different compost heights: 20, 40 and 60 cm. A mixture of CH4-CO2 (70-30) gas was fed through the bottom of each column. Methane concentration was measured at the feeding point, inside the columns at every 10 cm, and at the top of the column. Prior to the experiment, the composts physical and chemical characteristics were determined, according to standard laboratory methods for composts. A GEM-500 gas analyzer was used for determining gas composition. Best results for methane oxidation were obtained in the height of 20 cm of RM1 compost. This column removed 100% of methane during all the experiment, nevertheless, due to poor gas flow rate control, results were not concluding, therefore, it is necessary to confirm these results controlling the gas injection efficiently.