Microwave UV Comes to Texas?

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™ UV System. Before including the MicroDynamics™ 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™ 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™ 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.