NOVELTY - The system comprises a construct with a cylindrical conduit (101) configured for air access, a layer of mineralized waste (103) configured to surround the cylindrical conduit, a divider (105a, 105b) surrounding the layer of mineralized waste, a separation layer (102) present between the conduit and the layer of mineralized waste, and a second separation layer placed outside of the layer of mineralized waste. The mineralized waste: is aged for 5-30 years; has water content of 10-30%, a nutrient solution and a mineralized sludge; and is sifted by 2-4cm sieves.    USE - The system is useful in a solid waste landfill site for oxidizing methane (claimed) to produce substances such as formaldehyde, formic acid, carbon dioxide and water.    ADVANTAGE - The system is capable of effectively, safely and economically oxidizing the methane thus producing the formaldehyde like substances with high oxidation efficiency.    DETAILED DESCRIPTION - The system comprises a construct with a cylindrical conduit (101) configured for air access, a layer of mineralized waste (103) configured to surround the cylindrical conduit, a divider (105a, 105b) surrounding the layer of mineralized waste, a separation layer (102) present between the conduit and the layer of mineralized waste, and a second separation layer placed outside of the layer of mineralized waste. The mineralized waste: is aged for 5-30 years; has water content of 10-30%, a nutrient solution and a mineralized sludge; and is sifted by 2-4 cm sieves. A thickness of the layer of mineralized waste is 0.4-2 m. The cylindrical conduit is perforated at a lower two-thirds portion, and has a diameter of 40-100 mm. The separation layer has a thickness of 100-500 mm, and is composed of gravels. The gravels have a diameter of 50-150 mm, and are arranged with the larger sized gravels close to a center of the conduit. The layer of gravels has a thickness of 100-500 mm. The divider is placed between the separation layer and the layer of mineralized waste, between the conduit and the layer of mineralized waste and between the layer of mineralized waste and the separation layer, and is a porous net. An INDEPENDENT CLAIM is included for a method for oxidizing methane.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a system for oxidizing methane.    Conduit (101)    Separation layer (102)    Layer of mineralized waste (103)    Divider. (105a, 105b)