FO/RO system can treat difficult wastes

A method of combining forward osmosis (FO) with reverse osmosis (RO) desalination to treat difficult effluents has been developed by Catalyx, a product development company based in California.

In the TWO (Two Way Osmosis) system, sterile sodium chloride is recirculated past the FO membrane, allowing the pure water from the waste stream to be drawn to it due to the osmotic pressure difference, thus diluting it. The dilute solution is then run through a standard RO desalination system to recover pure water and reuse the brine to extract more water from the waste stream.

Catalyx says that these systems have been pilot-tested for the following applications:

  • Slaughterhouse waste: waste containing high BOD/COD levels from slaughterhouses is very difficult to treat, let alone recycle. The TWO systems have successfully dewatered this waste, to recycle the water back to process, and, at the same time, concentrate the waste into a very small volume suitable for anaerobic treatment for biogas generation.
  • Landfill leachate: water collected by the liners at landfills is a mixture of organics, heavy metals and a myriad of other contaminants. The TWO system has successfully reduced this waste by 80% in volume, to be disposed of or used in boilers as energy.
  • Ion-exchange regeneration waste: sulfuric acid is commonly used for regeneration in ion-exchange systems. The TWO system can concentrate this waste by a minimum of 50%. In areas where disposal of regenerant waste is by trucks or deep injection wells, the cost savings can be very high.
  • Textile and carpet-mill dyeing wastes: this type of wastewater is very difficult to treat without customized pretreatment systems. The TWO system can be designed in a “standard” configuration, which can be applicable to all different types of dyeing chemistry.
  • Concentration of sewage and animal farm wastewater to generate biogas: these wastes are typically very dilute, making biogas generation marginal from an economic perspective. The TWO system provides a simple, benign way to reduce the water volume, while increasing the COD concentration for enhanced biogas recovery.
  • Other applications for the TWO system include:

  • Tannery wastes
  • Oilfield-produced water
  • Cheese and dairy product wastes
  • Black liquor from paper production
  • Tailings from mining operations.
  • For more information, contact: Catalyx, 1200 N. Van Buren Suite A · Anaheim, CA 92807, USA.
    Tel: +1 714 630 2124
    Fax: +1 714-630-6928
    Email: [email protected]