NOVELTY - Use of a water flooded screw (WFS) type compressor (5) in a water scrubbing system for upgrading hydrocarbon gases and/or biogas, is claimed.    USE - The WFS type compressor is useful: in a water scrubbing system for upgrading hydrocarbon gases and/or biogas; gas treatment system; in a process for raising the methane concentration in a methane including gas; and in a compressing/water scrubbing/flashing/recovery (CSFR) (e.g. of methane) gas type upgrading system (e.g. Greenlane (RTM: CSFR system)) (all claimed).    ADVANTAGE - The support system for water treatment normally required for the WFS compressor is already intrinsic in the retained parts of the combined Greenlane (RTM: CSFR system) and is thus utilized, eliminating much complexity. The single stage WFS compressor: replaces the old two stage compressor, as the single stage WFS compressor do the job that previously needed two stages is because the cold water injected with the inlet gas on the WFS compressor provides lubrication, sealing and cooling of the compressor internals, where the cooling benefit permits a single stage and the injected water cools the gas during the compression process, which allows a much higher compression ratio to be used without over-heating of the compressor; requires no lubrication oil, which avoids contamination of the water scrubbing system and saves the cost of oil, which was previously a total loss system and thus wasted, and costs of contaminated oil disposal are avoided; eliminates inter-stage cooling and liquid separation equipment; requires no gas inlet separation, this was needed in old system to remove water mist and droplets that are naturally present in the water-saturated biogas, to prevent damage to the oil lubricated compressor, as the WFS compressor is water lubricated (and cooled) the water delivered with the biogas is beneficial; and requires no liquid separation of the gas after compression, because the water is separated and re-processed by the downstream system. Cooling of the gas after the single stage WFS compressor is optional, because this can be accomplished by the injected water. In WFS: partial scrubbing of the biogas will take place during compression due to the agitated close contact with the cold water that is injected into the WFS compressor, this reduces the required size and/or increases the available capacity of the new process system; and the water fed to the compressor for sealing and lubrication (10-30% of recycled water flow and chilled to 0.5-5 degrees C) is further used as process water in the scrubber to upgrade the raw biogas.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) a gas treatment system, or their plant and/or the process, comprising: either a WFS type compressor (5) to receive and discharge both water and the gas being treated, a scrubber (6) to receive at least the gas discharge from the compressor (directly or indirectly) and to receive scrubbing water, a stripper and/or flasher to receive the water and included gas output of the scrubber and to recycle water for use by one or both the compressor and scrubber, and a recovery system (8) for the gas from the scrubber; or a compressor to receive and compress a gas being treated in an at least substantially oil free environment which includes water, a scrubber to receive the compressed gas from the compressor and to scrub that gas with water, a recovery system for the water and at least some of die included gas of the water from the scrubber and to recycle at least part of that recovered water for use by the scrubber and/or compressor, and a recovery system for the gas from die scrubber;    (2) a process for raising the methane concentration in a methane including gas, comprising or including harvesting the gas (optionally with hydrogen sulfide removal) after water scrubbing after infeed gas pressurization in a water cooled and/or lubricated and/or sealed compressor;    (3) a WFS type compressor of a gas treatment system or used in the process; and    (4) gas treated by a system.    DESCRIPTION OF DRAWING(S) - The figure shows an improved system incorporating a WFS type compressor.    Motor (4)    WFS twin screw gas compressor (5)    Scrubber (6)    Recovery apparatus (8)    Water chiller (9)