Pilot-scale nanofiltration system as post-treatment for fertilizer-drawn forward osmosis desalination for direct fertigation

Abstract

The integration of the fertilizer-drawn forward osmosis with nanofiltration (NF) has been investigated to evaluate the performance of NF process as a post-treatment. The primary objective of this study is to optimize the operating conditions such as feed flow rate and feed concentration, while producing fresh water including low nutrient (N) concentration can be directly used for irrigation. Investigation of operating parameters at the pilot-scale level focused on specific water flux and ammonium sulphate rejection. Results from this study showed that NF process applied as the post-treatment can effectively reject the N concentration more than 90%. Although other factors such as the applied pressure and the cross-flow rates played a certain role in the performance of the pilot-scale NF process, the influence of the feed concentration was more significant on the specific water flux and N rejection.

Keywords:

• Desalination
• Fertilizer draw solution
• Forward osmosis (FO)
• Nanofiltration (NF)
• Fertigation
• Nutrient concentration

Acknowledgments

The National Centre of Excellence in Desalination Australia (NCEDA) supports this study. We are thankful to HTI, Inc. USA for supplying the FO membrane and Woongjin Chemical Korea for supplying the NF membrane.

Notes

Presented at The Fifth Desalination Workshop (IDW 2012), October 28–31, 2012, Jeju, Korea