In order to conceive of an efficient way to manage a landfill, we conducted an exemplary study of the Sudokwon Landfill Site in South Korea, with particular regard to the influence of energy recovery from waste. As a result of the BMP test, biogas production of demolition waste was much lower than household waste even in the same waste type. Gas production from the residual substance of energy recovery from waste (ash), waste soil, and the sludge landfill cover material was almost zero, but the solidified sludge showed 4.1 times greater than digested sludge due to the fewer pozzolanic reactions. Lysimeter test results show that the total amount of landfill gas was reduced to about 1/27 when combustible waste is buried after the recovery of energy, but, in order to be able to completely eliminate the landfill gas collecting system in a newly managed landfill, solidified sludge should not be disposed of in the landfill site. In addition, the maximum concentration of hydrogen sulfide was 60.9×10³ ppm, when total waste was mixed and landfilled. However, the concentration of hydrogen sulfide decreased to about 1/6 and the total load largely decreased to about 0.9% when applied to landfill waste after energy recovery.