CEC Projects

In 1997, the CEC research group discovered the efficacy of UV light for Cryptosporidium inactivation, and has been a leader in the continued effort to study and promote the use of UV for drinking water disinfection worldwide. Research completed over the past decade by CEC was instrumental in convincing the drinking water industry of UV's effectiveness at inactivating Cryptosporidium. Prior research looked only at high UV doses (1000 to 8000 mJ/cm²), or used insensitive analytical tools to measure the effect of UV on Cryptosporidium. It was accepted that UV was ineffective for killing cysts and oocysts. However, by using a mouse infectivity bioassay method instead of traditional oocyst excystation methods, Clancy and coworkers demonstrated that much lower UV doses (<10 mJ⋅cm^-2) were sufficient to achieve at least 4-log₁₀ inactivation of Cryptosporidium. Other researchers confirmed these results, and found similar results for Giardia inactivation. The USEPA added UV treatment to the toolbox for control of Cryptosporidium in drinking water derived from surface water sources in the Long Term 2 Enhanced Surface Water Treatment Rule. The USEPA UV Disinfection Guidance Manual (UVDGM) used the UV dose-response data developed by CEC to establish dose requirements for Cryptosporidium inactivation for drinking water disinfection applications.

Safe Water Solutions (SWS) L.L.C. CEC conducted performance evaluations of the SWS Cryptosporidium UV inactivation device in full-scale operation at two locations.

Aquionics, Corp. CEC conducted disinfection trials demonstrating that the UVP 61, a medium pressure UV system, was able to achieve at least 4-log inactivation of Cryptosporidium parvum oocysts in recreational (swimming pool) water.

WaterHealth International. CEC conducted disinfection trials demonstrating that the UVW Waterworks, a low pressure system designed for small systems (10 gpm), was able to achieve 6-log Cryptosporidium parvum oocyst inactivation.

Calgon Carbon Corporation. CEC conducted bench scale collimating beam studies to develop standard curves for low and medium pressure UV inactivation of Cryptosporidium parvum oocysts in water.

National Sanitation Foundation (NSF). CEC assisted in developing the "NSF Equipment Verification Testing Plan for Microorganisms Contaminant Inactivation by Ultraviolet Based Technology Used in Packaged and/or Modular Drinking Water Treatment Systems for Small Public or Private Water Supplies."

National Sanitation Foundation. Under the Environmental Technology Verification program, developed in partnership by the U.S. Environmental Protection Agency and the National Science Foundation, CEC conducted a demonstration scale study showing that Cryptosporidium oocysts were inactivated using medium pressure UV in a 200-gpm system. (Bukhari et al, JAWWA, September 2000)

Associated Engineering. CEC assisted the Regional Municipality of Waterloo in gaining approval of first UV system for surface water disinfection in Ontario.

Portland, Oregon, UV Reactor Validation Center. CEC is part of a team with Carollo Engineers that developed a full-scale North American test site for validation of UV reactors. UV reactors can be tested at this location at flow rates up to 50 mgd, using criteria established by the U.S. Environmental Protection Agency in the guidance manual for the Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR).

Seattle, Washington. CEC provided third party oversight of the bioassay validation program for a 180 MGD UV system at Seattle's Cedar water treatment plant.

Hazen and Sawyer. CEC conducted bench scale studies on the feasibility of UV disinfection of the New York City Catskill-Delaware supply.

ITT - Wedeco. CEC conducted full-scale UV reactor validations of drinking water and wastewater using coliphage T1, which has a dose response similar to Cryptosporidium, reducing the reduction equivalent dose (RED) bias thus allowing better characterization of the reactors.