Abstract: A method of controlling the recovery of landfill gas from a sanitary landfill and apparatus for performing the method. Landfill gas, which mainly consists of methane and carbon dioxide, is formed by anaerobic decomposition of the organic content of the refuse. This process develops a very small amount of heat. If more gas is drawn from the sanitary landfill than is formed by the anaerobic decomposition, air is drawn into the landfill. The decomposition thereby becomes aerobic, developing large quantities of heat and increasing the content of carbon dioxide and nitrogen in the gas. According to the disclosed method, the temperature of the gas from each gas well is measured, thereby providing information for controlling the flow of gas from the corresponding wells. The apparatus disclosed by the invention comprises a control chamber connected to one or more gas wells on the one hand and to a gas furnace over a gas fan on the other hand.

Abstract: A method of purifying flue gases from refuse incineration by cooling and of recovering heat energy as well as an arrangement for performing the method. According to the method the flue gases are cooled in three stages, with the most beneficial structural material with regard to the temperature range, process conditions, and economy being selected in each cooling stage among the materials glass, plastic or alloyed steel. The sizes of the various cooling surfaces are determined such, that the temperatures of the flue gases immediately before the last cooling stage lie closely above the water dew point. The arrangement disclosed by the invention comprises a first cooling member, a second cooling member connected thereto, and a third cooling member connected to the latter and having its outlet connected to a droplet separator which is followed by a flue gas fan which in turn is connected to a chimney.