Site Specific Testing of UV Disinfection at a Trickling Filter Plant

The St. Joseph WPCP currently has no existing disinfection facilities. With the Missouri Department of Natural Resources (MDNR) moving toward requiring all National Pollutant Discharge Elimination System (NPDES) permit holders to disinfect plant effluent. The e Coli permit limit indicated in a proposed permit received by the City on February 26, 2009 is anticipated to be a 30 day mean of 206 E. coli colonies per 100 ml with no single sample maximum. Both bench scale and demonstration testing were conducted for both:UV Low Pressure - High Intensity UVBulk Sodium HypochloriteAdditional water quality data was also collected during the testing to help establish the design parameters for the UV systems. UV demonstration study was completed comparing the Trojan 3000+ and WEDECO TAK 55 from May 21, 2009 to August 31, 2008. This technical memorandum provides a summary of the results of both the bench and demonstration scale testing. Results of this study indicate that UV can be effectively used to achieve the disinfection requirements at this plant.