NOVELTY - Apparatus for recovering water from a source water, comprises a forward osmosis unit configured to be supplied with the source water and a draw solution, the forward osmosis unit configured to osmotically transfer water from source water into draw solution, where output from forward osmosis unit comprises diluted draw solution and concentrated source water; and a draw solution concentration unit comprising nanofiltration unit configured to be supplied with a diluted solution obtained downstream of forward osmosis unit and to concentrate the diluted solution, thus producing water.    USE - The apparatus and methods are useful for recovering water from source water; and for producing biogas from source water (all claimed).    ADVANTAGE - The apparatus or methods provide low energy consumption, less membrane fouling and requiring very limited feed water pre-treatment.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are:    (1) a method of recovering water from a source water comprising: (a) supplying the source water and a draw solution to a forward osmosis unit; (b) osmotically transferring water from the source water into the draw solution in the forward osmosis unit; (c) outputting diluted draw solution and concentrated source water from the forward osmosis unit; (d) supplying a diluted solution obtained downstream of the forward osmosis unit to a draw solution concentration unit; and (e) concentrating the diluted solution in the draw solution concentration unit, thus producing water;    (2) an apparatus for producing a biogas from a source water, comprising a forward osmosis unit configured to osmotically transfer water from the source water into a draw solution, output from the forward osmosis unit comprising diluted draw solution and concentrated source water; and a bioreactor configured to produce the biogas from the concentrated source water; and    (3) a method of producing a biogas from a source water, comprising: (a) supplying the source water and a draw solution to a forward osmosis unit; (b) osmotically transferring water from the source water into the draw solution in the forward osmosis unit; (c) outputting diluted draw solution and concentrated source water from the forward osmosis unit; and (d) producing the biogas by bioreacting the concentrated source water in a bioreactor.