Microwave UV Comes to Texas?

Abstract

The North Texas Municipal Water District (NTMWD) is looking to install ultraviolet light (UV) disinfection at the Floyd Branch Regional Wastewater Treatment Plant (Floyd Branch). Treatment plant staff is intrigued by the performance and ingenuity of the latest microwave UV reactor manufactured by Severn Trent Water Purification (Severn Trent), the MicroDynamics TM UV System. Before including the MicroDynamics TM UV System as one of several qualified bidders for their project, and because the technology is relatively new in the marketplace, the NTMWD required that Severn Trent provide and test a pilot at no cost to the NTMWD. As a result, Severn Trent contracted Carollo Engineers, P.C. to oversee pilot testing at Floyd Branch. NTMWD agreed to assist with daily monitoring, including field inspections and laboratory work (UV transmittance and E. coli monitoring).There is an important secondary goal to this pilot testing. Previously, the consulting firm Hytecon conducted a detailed bioassay of the MicroDynamics TM UV System at the Downingtown Wastewater Treatment Plant. This detailed bioassay examined the disinfection of T1 coliphage, a surrogate for coliform. Carollo has analyzed the data from the Downingtown testing and compared those results to the results at Floyd Branch. The goal of the comparison is to determine the accuracy and appropriateness for designing a MicroDynamics TM UV System based upon the more expansive and detailed Downingtown testing. The important underlying question is whether detailed pilot scale testing at one site can be repeated at other locations.The testing included concentrated short term testing of performance as well as longer term monitoring over a period in excess of 2 months. Testing also included an analysis of performance of the automatic physical wiping system to maintain sleeve transmittance. DISINFECTION TESTING AT FLOYD BRANCH Collimated Beam TestingTwo benchtop UV collimated beam tests were performed on E. coli during the first day of pilot testing. The two samples for E. coli collimated beam analysis were sent to BioVir Laboratories in Benicia, CA. The test samples were analyzed at UV dose values of 0, 5, 10, 15, and 25 WEFTEC 2010

Disinfection and Antimicrobial Processes

“…Virgadamo et al (2010) presented a case study that showed different procurement processes and assumptions made resulted in significantly different maintenance costs for UV systems at a treatment plant. A pilot-scale study was conducted and reported for a microwave UV system in Texas (Victor et al, 2010).…”