The forward osmosis system was originally developed by NASA for use as a spacecraft or planetary base water recycling system. Winery Wastewater Recycling Systems (WWRS) has recently completed a one-year demonstration project of a forward osmosis (FO) water recycling system at a Napa Valley winery. Results of this test demonstrated the viability of FO for the treatment of winery wastewater. FO was shown to be capable of achieving high water recovery ratios with high solids feeds and producing high purity product water suitable for industrial reuse at a low cost. A report on the tests is available by clicking the Downloads menu.
- Forward osmosis (FO) is based on generating an osmotic potential across a water permeable membrane.
- It is the same process used in the root zones of plants to extract water from soil and in the digestive systems of animals.
- The flow of water across the FO is driven by osmotic forces rather than pressure.
- As a result FO process are ideal for treating high solids feeds that have a tendency to precipitate solids as they are concentrated.
- The FO system is run in a batch mode where the feed tank is concentrated during a run.
- At the end of the run the high organic and inorganic residual concentrate in the feed tank must be disposed of at the East Bay Municipal Utility District Wastewater Treatment Plant or dried on site for disposal as a solid waste. WWRS offers brine drying technologies.
- Technology is currently being developed by the Army and NASA as the next generation water recycling system.
Forward Osmosis Water Recycling System Process Flow Diagram
- In this process the feed tank is filled and then recirculated through feed side of forward osmosis module.
- A high salt solution, called the osmotic agent (OA), is circulated through the Draw Loop and passes the opposing side of the forward osmosis module.
- Water then flows across a membrane from the feed into the OA.
- The diluted OA is then passed through a reverse osmosis (RO) or distillation module where purified water is produced and the OA is re-concentrated and returned to the forward osmosis module.