Patent ID: 8221629

Claim:
A process for removing water from a first solution, said process comprising: i) providing a first solution comprising seawater, brackish water or waste water; ii) forming a second solution having a higher osmotic potential than the first solution by dissolving a water soluble solute in water, the second solution substantially free of components that cause membrane fouling or scaling; iii) directly adding into the second solution an additive selected from the group consisting of an anti-scaling agent, an anti-fouling agent, and combinations thereof; a) positioning a first membrane between the first solution and the second solution, such that water from the first solution passes across the first membrane to dilute the second solution by direct osmosis, and b) passing the diluted second solution through a second membrane, wherein the second solution contains solute species too large to pass through the pores of the first selective membrane and the second membrane.