A process for the landfill gas treatment and separation of methane gas and carbon dioxide gas and for producing liquid natural gas, carbon dioxide and compressed natural gas products comprises: (a) gathering a landfill gas stream from a solids waste treatment landfill site with a vacuum collection system and pressurizing the collected gas stream to above atmospheric pressure; (b) cleaning the landfill gas stream to remove condensed water vapour and trace sulphur and hydrocarbon compounds; (c) conducting the cleaned landfill gas into a four-stage gas compressor; (d) increasing the pressure and simultaneously cooling the landfill gas stream at each compression stage, the first stage increasing the gas pressure from atmospheric to 70 psig, the second stage increasing the gas pressure to 240 psig, the third stage increasing the pressure to 630 psig and the fourth stage increasing the pressure to above 180 psig; (e) intercooling the compressed landfill gas stream between each stage to maintain a near ambient temperature to effect cooling, condensing and removing water vapours and heavy hydrocarbon vapours; (f) cooling the compressed landfill gas stream from the fourth compression stage to around 20 F to condense most of the carbon dioxide vapour; (g) separating liquid carbon dioxide from a methane rich gas stream; (h) scrubbing the methane rich gas stream with a solvent fluid injected at 50 F and 1800 psig into a contactor vessel to absorb most of the remaining carbon dioxide to form a carbon dioxide-rich solvent stream and a purified compressed methane gas stream; (i) conducting the carbon dioxide-rich solvent fluid into a first flash vessel to decrease the pressure to 630 psig; (j) recycling a gas mixture stream released from the first flash vessel at 630 psig to the suction of the fourth stage compression; (k) conducting the carbon dioxide-rich solvent stream from the first flash vessel to a second flash vessel to decrease the pressure to 240 psig; (l) recycling a second gas stream from the second flash vessel at 240 psig. to the suction of the third stage compression; (m) conducting the carbon dioxide-rich solvent from the second flash vessel to a third flash vessel to decrease the pressure to 70 psig; (n) recycling a third gas mixture stream at 70 psig to the suction of the second stage compression; (o) heating and spraying the heated carbon dioxide-rich solvent into a regenerator vessel at near atmospheric pressure to release most of the remaining carbon dioxide; (p) recycling the gas mixture stream from the regenerator vessel to the suction of the first stage compression; (q) pumping a carbon dioxide-lean solvent fluid from the regenerator to increase its pressure to above 1800 psig; (r) conducting the pressurised solvent fluid into a reverse heat exchanger where the carbon dioxide-rich solvent stream from the third solvent flash vessel is heated and the carbon dioxide-lean solvent stream from the regenerator vessel is cooled; (s) further cooling the carbon dioxide-lean solvent stream flowing from the heat exchanger to below 50 F before entering the contactor vessel to repeat the scrubbing of the methane-rich gas stream flowing from the carbon dioxide condensing step; (t) transporting and storing the purified methane gas flowing from the gas contactor vessel to a high-pressure gas storage vessel; (u) treating the carbon dioxide liquid stream from the fourth compression stage to remove most of the dissolved hydrocarbon contaminants by expansion in a flash vessel at above 1800 psig to 200 psig and by physical adsorption of gases in an activated carbon bed; and (v) transporting and storing the purified liquid carbon dioxide into a liquid carbon dioxide storage vessel.    USE -   For treating solids waste landfill gas with separation of methane and carbon dioxide.    ADVANTAGE -   Economically produces methane and carbon dioxide gas and high quality liquefied natural gas, liquefied carbon dioxide and compressed natural gas liquids. Reduces emissions from landfills and provides alternative energy-saving process for the production of carbon dioxide.