title: Blended fertilizers as draw solutions for fertilizer-drawn forward osmosis desalination.
abstract: In fertilizer-drawn forward osmosis (FDFO) desalination, the final nutrient concentration (nitrogen, phosphorus, potassium (NPK)) in the product water is essential for direct fertigation and to avoid over fertilization. Our study with 11 selected fertilizers indicate that blending of two or more single fertilizers as draw solution (DS) can achieve significantly lower nutrient concentration in the FDFO product water rather than using single fertilizer alone. For example, blending KCl and NH(4)H(2)PO(4) as DS can result in 0.61/1.35/1.70 g/L of N/P/K, which is comparatively lower than using them individually as DS. The nutrient composition and concentration in the final FDFO product water can also be adjusted by selecting low nutrient fertilizers containing complementary nutrients and in different ratios to produce prescription mixtures. However, blending fertilizers generally resulted in slightly reduced bulk osmotic pressure and water flux in comparison to the sum of the osmotic pressures and water fluxes of the two individual DSs as used alone. The performance ratio or PR (ratio of actual water flux to theoretical water flux) of blended fertilizer DS was observed to be between the PR of the two fertilizer solutions tested individually. In some cases, such as urea, blending also resulted in significant reduction in N nutrient loss by reverse diffusion in presence of other fertilizer species.
authors.affiliation: School of Civil and Environmental Engineering, University of Technology, Sydney (UTS), Post Box 129, Broadway, NSW 2007, Australia.
authors.forename: Sherub
authors.initials: S
authors.lastname: Phuntsho
authors.forename: Ho Kyong
authors.initials: HK
authors.lastname: Shon
authors.forename: Tahir
authors.initials: T
authors.lastname: Majeed
authors.forename: Ibrahim
authors.initials: I
authors.lastname: El Saliby
authors.forename: Saravanamuthu
authors.initials: S
authors.lastname: Vigneswaran
authors.forename: Jaya
authors.initials: J
authors.lastname: Kandasamy
authors.forename: Seungkwan
authors.initials: S
authors.lastname: Hong
authors.forename: Sangyoup
authors.initials: S
authors.lastname: Lee
mesh_terms: D005308:Fertilizers / Q000032:analysis*; D009584:Nitrogen / Q000032:analysis*; D009995:Osmosis; D010758:Phosphorus / Q000032:analysis*; D011188:Potassium / Q000032:analysis*; D054712:Salinity; D018508:Water Purification / Q000379:methods*
chemical_list: D005308:Fertilizers; D010758:Phosphorus; D009584:Nitrogen; D011188:Potassium