Asymmetric integrally skinned capillary tubes were produced from the polymers PEI (polyetherimide) and PVP (polyvinylpyrrolidone) for vapour permeation modules which were applied for the separation of water from organic compounds and gases. Water treatment and recovery of desirable organic compounds was achieved. The capillary tubes had intrinsic permeability coefficients of 7.5 x 10(-7) mol/m(2).sPa for water and 1.6 x 10(-9) mol/m(2).s-Pa for 1-propanol for a 1:1 mass ratio vapour feed mixture under pyrolysis conditions. The vapour was fed at the interior of the capillary tubes with total pressure of 30 kPa; the permeate total pressure was 14 kPa, and the temperature was 86 degrees C. Modules, with surface areas up to 1.0 m(2), were constructed and tested with feed flow rates as high as 4 kg/h with a process development unit. Tests were performed with the vapours from wood chips and contaminated soils subjected to vacuum pyrolysis.