A zero-discharge landfill process is disclosed herein. The process described in the present invention recycles the exhaust gases from a combustion engine which reheats the landfill and provides moisture. Additionally, the CO2 from the exhaust gases releases additional methane. Methane production in landfills can thus be enhanced by the method of the present invention. Furthermore, a portion of the exhaust gas can be used to cultivate algae in a cultivation tank. The cultivation of the algal species is enhanced in the presence of water, CO2, CO, and the elevated temperatures. Optionally, a first portion of the cultivated algae can be passed through the landfill to increase methane production in the landfill and a second portion of the cultivated algae can be transferred to a biodiesel production tank, for the conversion of the one or more algal oils and lipids to a biodiesel or a biofuel by a transesterification reaction.