A methane purification system includes one or more components that cool and compress an input methane-containing gaseous mixture stream to form a first methane-containing gaseous mixture stream. A filter-separator in fluid communication with the one or more components receives the first methane-containing gaseous mixture stream removing water therefrom to form a second methane-containing gaseous mixture stream. An activated carbon station receives the second methane-containing gaseous mixture stream removing hydrogen sulfide therefrom to form a third methane-containing gaseous mixture stream. A methanol scrubber that receives the third methane-containing gaseous mixture stream or an expanded stream therefrom, removing carbon dioxide to form a fourth methane-containing gaseous mixture stream. A final stage separator produces a purified methane stream from the fourth methane-containing gaseous mixture stream or an expanded stream therefrom.