Abstract: The invention relates to an electrodialysis device for the desalination of water for oil and gas applications comprising: a membrane stack comprising alternating cation- and anion-exchange membranes (2.1, 2.3) and; a plurality of spacers (2.2, 2.4), each spacer being arranged between two successive membranes; wherein at least one of the spacers (2.2, 2.4) comprises a recessed area (3.2) and a non-recessed area (3.3), the non-recessed area (3.3) surrounding the recessed area (3.2), and wherein: the spacer (2.2, 2.4) comprises a central opening (3.1) within the recessed area (3.2); the spacer (2.2, 2.4) is provided with at least four orifices (3.4, 3.5) within the non-recessed area (3.3); the spacer (2.2, 2.4) is provided with respective channels (3.6) which connect at least two of the orifices (3.4) with the central opening (3.1); and one cation-exchange or anion-exchange membrane (2.1, 2.3) is accommodated in the recessed area (3.2).

Abstract: The underwater process comprises the following steps, carried out underwater, at the bottom of a body of water: providing a base fluid (38) comprising at least a viscosifying compound, obtaining a concentrated viscosifying solution (34) from the base fluid (38), providing a processed water of controlled salinity (36), diluting the concentrated viscosifying solution (34) with the processed water of controlled salinity (36) to form the viscosified water (32).

Abstract: A method for treating and disposal of fluid fine tailings utilizes two stages of thickening prior to disposal of the thickened tailings. The fluid fine tailings are adjusted to a sand-to-fines ratio of 0.5 to 1.3 using hydrocyclones or centrifuges in required. In a first stage of thickening a first flocculant is added to the fluid fine tailings which are fed to one or more conventional thickeners to produce a pumpable thickened tailings underflow having a solids content of between about 20 wt % to 40 wt %. The pumpable thickened tailings underflow is centrifugally pumped through a pipeline towards a disposal area. Adjacent the disposal area a second flocculant is added to the pumpable tailings underflow in a second stage of thickening to flocculate the tailings sufficient to produce a secondary thickened tailings underflow which when deposited has a solids content of about 50 wt % or higher at least one day after disposal.

Abstract: A composition, comprising an azo compound in the form of granules having a diameter size of between 200 &mgr;m and 10 mm, the cumulative pore volume of said granules being between about 0.2 and about 2 ml per gram of composition. A process for preparing the composition is also provided, which comprises providing a wetted powder comprising the azo compound, effecting granulation by passing the wetted powder under mechanical stress, through a die, and then drying the granules so obtained at a temperature of at or less than about 45° C.