Novel Continuous Treatment of Wastewater by the Addition of Recyclable Propane Gas


Wastewater management is an issue that is increasingly requiring more immediate attention as the freshwater crisis expands globally. The current processes implemented in the U.S. account for 2% of total U.S. electricity. Publicly owned treatment works (POTWs) operations resulted in energy-related emissions which then led to a total emission of 15.5 million metric tonnes of carbon dioxide in 2000. Additionally, in 2012 the U.S. spent 102 billion dollars to build and update wastewater treatment plants; analysis shows this number to increase to over 74 billion dollars by 2040. The commercial technology used today revolves around a multi-step process. First, the non-food components are separated from the wastewater. Then disinfection treatments in the form of chlorination and ultraviolet are used, which both have substantial energy consumption, in the wastewater. Finally, coagulation and sedimentation processes are enhanced by the chemical addition of ferric salts and lime which consequently results in improved removal of solids and toxic pollutants. These steps are often coupled with CH4 recovery which facilitates microbial degradation of organic matter, but unfortunately also accounts for up to 60% of the energy use in waste water treatment plants. Also, the pumping systems involved in these processes add another 10-15% of energy cost. The conventional processes are also becoming more and more difficult to continue as the leachate management in landfills (water that entered a landfill and extracted constituents from it) steadily cost more to control. The constituents in the leachate also can interfere with commercial waste water processes. Ultimately a non-chemical, economical, energy-efficient, and reusable approach is needed to separate water and dissolved organics and inorganics from waste water streams.


This process involves using a physical phase change of propane gas, which is recycled after, to separate the impurities from waste water. When the propane gas is added to the waste water at mild pressure and low temperature, it forms clathrate propane hydrates. This procedure yields a solid phase containing the concentrated inorganic and organic compounds and also propane hydrates due to the liquid water encapsulating the propane gas. Subsequently, the ambient conditions cause the water to separate from the propane. Finally, the separated water is passed through biochar to remove any remaining contaminants and then discharged to the environment. The solid phase that was formed in this process can also be further treated for methane extraction.


- No chemicals required - The process is catalytic unlike all other waste water treatments - Only propane gas is needed for this procedure - After the separation is done, the clathrate automatically decomposes once warmed above 10 degrees Celsius - The propane gas is recovered and recycled, so no gas is consumed in the process - This method and apparatus is novel and completely green


-Used to separate contaminants and impurities from waste water streams -The solid phase formed in this method can be further processed for methane extraction, so a potential energy source also lies in this procedure.

Patent Status

Provisional patent

Stage Of Development

Serial Number: 62/856,437

Licensing Potential

Development partner,Commercial partner,Licensing

Licensing Status

Available for Licensing

Additional Info Please note, header image is purely illustrative. Source:, unsplash license
Patent Information:
Case ID: R050-9043
For Information, Contact:
Donna Tumminello
Assistant Director
State University of New York at Stony Brook
Devinder Mahajan