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Low Cost and Low Energy Forward Osmosis for Wastewater Treatment

Technology Overview

The rapid evolution of forward osmosis (FO) within the last decade has led to the commercial implementation of the technology in the power generation sector and will address the desalination markets and the re-use needs for industrial need. Unlike reverse osmosis which uses the application of high applied pressures, FO involves the energy free and spontaneous transfer of water through a semi-permeable membrane from a “contaminated” wastewater stream to a draw solution of higher ionic strength. Conventional draw solutions are challenging because the salt cannot be easily removed from the used or saturated draw solution following FO presenting a barrier to commercial implementation. The proposed technology has addressed this challenge through a proprietary FO process using “switchable” draw salt (mixture of trimethylamine and CO2) as the draw solution. During FO, the draw solution is diluted by fresh water flowing across the membrane. The application of moderate heating (~70 degC) to the diluted draw solution “switches” the salt into the two commodity gases that can be readily removed leaving behind clean water as the final process product. The gases are recovered and recycled to regenerate the concentrated draw solution in a continuous closed loop process. The technology provider has designed, built, and tested the full process at pilot scale using fully scalable off-the-shelf equipment and has completed a 1st order design basis to 250 m3/day scale and can project scalability to thousands of cubic metres per day. 

The technology provider is seeking for a technology adaptor either as a partner or licensee.

Technology Features & Specifications

The key feature of this technology is the ability to remove clean water form highly contaminated, high mineral content waste streams using low energy inputs. Typically, these waste streams are thermally evaporated using energy intensive methods that are costly and produce large amounts of greenhouse gases. The FO approach can remove water which is suitable for re-use and potentially potable needs can be achieved from incoming feeds having TDS levels above 6% wt which is the upper limit of reverse osmosis to well beyond 20% wt TDS (60,000 to 200,000 ppm respectively). It achieves 40% lower energy consumption than closest in-class FO technology. The process is capable of extracting up to 80% of the original waste volume as clean fresh re-usable water.

Potential Applications

All sectors requiring the treatment of high dissolved mineral and salt content waste water streams would have potential interest in this technology. This includes

  • Oil and gas production
  • Zero liquid discharge (ZLD)
  • Wastewater treatment
  • Desalination
  • Boiler and cooler waste water
  • Flue gas water treatment
  • Food and beverage production. 

Market Trends and Opportunities

Low cost high efficiency solutions that produce fresh water from unusable water sources are in high global demand. Water scarcity and clean water acquisition costs have led to the rapid expansion of desalination or demineralization capacities for the generation of clean water. The demand for continuous improvement of these facilities provides Forward Water with an opportunity to supply a better solution than the existing thermal processes. Desalination and the global Oil and Gas industries are the two largest markets that require fresh water for operations and the need for water treatment. Global Water Intelligence (GWI) predicts that salt removal and wastewater recycling technologies are expected to become an essential ingredient in operational strategy, growing by 11.4% over the next five years to reach a total market value of almost $12 Billion by 2025 for industrial desalination alone. In addition, the seawater desalination market is expected to grow from $11.7 to $19.1 Billion by 2019 (Frost & Sullivan). By partnering with companies having global scope and operational capabilities, This company is addressing this specific growing opportunity.

Customer Benefits

The FO system delivers a compact, modular, low fouling, and robust water treatment solution to the wastewater management market with the following benefits over conventional treatment:

  • Low energy requirements (including solar thermal)
  • Utilises low grade waste heat
  • Treats TDS levels far beyond the reach of RO
  • Mobile design solution
  • Easily integrated with and extends the capabilities of existing treatment platforms
  • Applicable to multiple sectors.

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