received by the International Bureau on 21 September 2015 (21.09.15).

1. A process of dewatering of sugarcane juice through forward osmosis (FO) employing wasted salt bittern (mother liquor after separation of common salt) as draw solution wherein the said process comprising the steps of:

(i) evaporating pure sea bittern in solar pan to obtain draw solution wherein the bittern may be of natural origin or derived from sea-, lake- or sub-soil brine and having density in the range of 28-38 °Be with viscosity (η) in the range of 3-1 13 cP and osmotic coefficient in the range of 1.4-3.3;

(ii) clarifying freshly expelled raw sugarcane juice as feed solution through treatment with 2-3 % charcoal;

(iii) maintaining the volume ratio of draw solution to feed solution from 1 :5 to 20: 1 ;

(iv) circulating the juice as feed solution and bittern as draw solution through a forward osmosis (FO) stack fitted with high flux thin film composite polyamide membrane for a period in the range of 3-5h having temperature in the range of 15 °C to 45 °C to obtain dewatered feed;

(v) Subjecting the draw solution after FO for chilling at a temperature in the range of 2-8°C to crystallize out Epsom salt.

2. The process as claimed in Claim 1 , wherein selective permeation of water during forward osmosis was effected using a thin film composite polyamide membrane with active membrane surface area 0.005-0.006 m , which when operated in reverse osmosis mode for desalination of 2000-3000 ppm feed solution gave a flux of 25-30 L/(m h) and salt rejection of 93-96% at 5-8 bar operating pressure and flow rate of the pump 1.6-1.9 LPM.

3. The process as claimed in Claim 1 , wherein the temperature of feed solution was in the range of 15-45 °C and the inlet pressure at the feed side was 0.5-2.0 bar.

4. The process as claimed in Claim 1 , wherein the sugarcane juice had an initial concentration of sucrose in the range of 8-12% (w/v) and a final concentration of 15-60%) (w/v) after forward osmosis.

5. The process as claimed in Claim 1 , wherein the average flux during forward osmosis was in the range of 5- 15 L/(m²h).

6. The process as claimed in Claim 1 , wherein, in comparison to concentration through multiple effect evaporation, an energy saving of 97%> was computed for four-fold concentration of sugarcane juice by forward osmosis with 33.5 °Be sea bittern as draw solution, and 8: 1 volume ratio of draw solution to sugarcane juice in 3-5 h with both feed and draw solutions under constant recirculation.

7. The process as claimed in Claim 6, wherein the loss of sucrose from feed solution to draw solution was 1 -3 % (w/v).

8. The process as claimed in Claims 1 , wherein back diffusion of inorganic mineral constituents from bittern draw solution into sugarcane juice was insignificant.

9. The process as claimed in Claims 1 , wherein simple water washing of the membranes after forward osmosis helps their regeneration with < 5%> reduction of initial flux.

10. The process as claimed in Claims 1 , wherein use of sea bittern of 32.5-33.5 °Be as draw solution, and its dilution by 9- 1 1 % in the course of forward osmosis, permits the recovery of Epsom salt (MgS04.7H₂0)in 95-99% purity upon chilling to 5 °C, compared to a purity level of 80-85%) obtained with the undiluted bittern as such.