The New York State Center for Clean Water Technology Granted a United States Patent for a Novel, Nitrogen-Removing Onsite Wastewater Treatment System
April 15, 2024 - The New York State Center for Clean Water Technology (CCWT) at Stony Brook University was recently awarded a US Patent for its FlexTreat Biofilter™ wastewater treatment system. FlexTreat™ is a prefabricated, plug-and-play, continuous-flow nitrogen-removing onsite wastewater treatment system that uses inexpensive and readily available filtration media and woodchips to convert ammonia to harmless nitrogen gas. Its flexible and scalable design will be essential in replacing existing archaic residential cesspools that do not remove nitrogen that can harm public health, groundwater, and surface waters.
FlexTreat™ was designed by Mr. Frank M. Russo, P.E., Associate Director for Wastewater Initiatives at the Center. CCWT and the Research Foundation for SUNY’s Intellectual Property Partners jointly applied for and received the US patent. The system design features a variety of flexible, operator-friendly controls to adjust various process parameters to ensure nitrogen reduction continues under varying wastewater strength and flow that can significantly differ from home to home.
FlexTreat™ was first tested in a pilot configuration by CCWT members Dr. Xinwei Mao and doctoral candidate Mr. Siwei Chen, together with Mr. Russo at the Center’s Wastewater Research and Innovation Facility (WRIF) that receives raw sewage from Suffolk County Sewer District No. 10. The pilot design
consisted of a series of column-size tanks at the WRIF (See Photograph No. 1). Three-years
of testing and refining of the design demonstrated that the FlexTreat™ process could
consistently generate effluent with a total nitrogen concentration of 5 mg/L. Results
from the three-year study were published in two international peer-reviewed articles
published in Chemosphere and the Journal of Water and led by Mr. Chen (Chen et al.,
2022, 2024).
Concurrent with the performance testing of the pilot system at the WRIF, a full-size
FlexTreat™ prototype was precast by Roman Stone Construction and delivered, built,
and installed in the ground at the WRIF. The system was brought online in late 2022 and has shown the ability to achieve less than 10 mg/L of total nitrogen based
on direct and continuous measurements made by a patented nitrogen sensor invented
by Dr. Qingzhi Zhu, a CCWT scientist.
The Center’s scientists and engineers continue to evaluate the performance of FlexTreat™, refining design elements to lower costs and simplify operations. CCWT staff member Mr. Thomas Varley, a 40-year veteran of wastewater systems, has worked closely with Mr. Russo to make several system modifications that have decreased required maintenance and improved functionality. Testing will also involve stressing the system with higher flows and higher nitrogen influent to determine the maximum loading rate and to optimize the cost-effective performance point. In the near term, the Center will enter FlexTreat™ into the SCDHS Article 19 process for approval while concurrently exploring NSF 245 requirements to enter the system into the global market.
Related Publications
Chen, S., Wang, M., Russo
, F.M., Gobler, C., Mao, X. (2022). Efficient nitrogen removal from onsite wastewater by a novel continuous flow biofilter. Chemosphere,300, 134642.
Chen, S., Wang, M., Lin, D., Russo, F. M., Gobler, C. J., & Mao, X. (2024). Biofiltration matrix optimization for efficient nitrogen removal from domestic onsite wastewater. Journal of Water Process Engineering, 60, 105208.
Update May 2, 2024 - On Thursday, May 2nd, Center Associate Director, Frank M. Russo, P.E., was presented with a plaque for his patent related to FlexTreat Biofilter at the Annual Meeting of the SBU Chapter of the National Academy of Inventors.