Evoqua United States - Canada - EN

UV Disinfection Offers a Safe and Efficient Replacement for Old Process

Scottsburg, IN makes the switch from open channel to closed vessel ultraviolet disinfection

‚ÄčThe City of Scottsburg is located in Indiana between Louisville, Cincinnati, and Indianapolis. Scottsburg maintains a healthy balance between commercial, industrial and residential community with a celebrated history and bright future. Scottsburg has put a large emphasis on "quality of life" and it shows in their beautiful parks and lively downtown square.

Challenge

The Scottsburg Indiana WWTP had been using open channel ultraviolet (UV) disinfection to treat wastewater before it was discharged. This configuration of placing UV lamps in an open channel has historically been the industry standard. The industry went with this original configuration largely because early municipal adopters of UV disinfection retrofitted chlorine contact basins in this manner. Even yet today, when new plants are constructed, the norm is to install open channel UV systems because they are familiar to engineers and operators. These open, gravity flow channels suffer from many disadvantages; poor hydraulic mixing, very large footprint, expensive to build, difficult to maintain and are vulnerable to fluctuation in flowrate.Discharged wastewater from communities often becomes drinking and recreational water for downstream communities. Chlorine can react with naturally occurring compounds in the water to produce disinfection byproducts (DBPs). DBPs have shown evidence to be a human carcinogen. Unlike chlorine, with UV disinfection, there is no transportation, storage or the risk of handling of toxic or corrosive materials. In addition, microorganisms, such as Cryptosporidium and Giardia, are exhibiting a growing tolerance to chlorine. Removing these dangers supports public health, nature and aquatic species.


Solution

The City selected a more efficient approach by containing the waste stream in a pipe to disinfect the water within a closed vessel. Closed vessel ETS-UV™ disinfection systems are easy to install within existing pipework and new construction does not require the large footprint of concrete channels. Disinfection into a closed pipe will ensure optimized hydraulics and prevent the operator for exposure to the wastewater and UV light.

ETS-UV systems are designed by utilizing Computational Fluid Dynamics (CFD) modeling to design and optimize how the systems will perform. More importantly, this allows systems to be designed to deliver the highest performance for the least power and headloss.

Two ETS-UV SW-835-14 systems were chosen. The UV chamber is fabricated from 316L stainless steel and contains an automated wiper to keep the quartz free from fouling. The chamber also features an access hatch which makes routine maintenance much easier and convenient for operators. Each chamber contains medium pressure lamps, which can be removed with effluent in the chamber. The lamps use a Twist-Lok lamp connector for a safe and easy connection. Municipal plants like Scottsburg that only disinfect seasonally can often achieve a two year lamp life.

" We have been impressed with the ease of use of the closed vessel UV system. The automatic wipers keep the quartz sleeves clean without constant manual cleaning and overall, the installation is cleaner and much more compact. The units are installed in a building with climate control making it easy to service the unit or change lamps in a matter of minutes, keeping our employees safe and out of the weather. Water level control issues have been designed out and we appreciated the improved safety that these modern systems provide to the plant staff. "

Jason Combs, Facility Manager