USFilter Wallace & Tiernan Products has introduced a new ultraviolet (UV) system for drinking water applications. Ideally suited for small- and medium-sized community drinking water systems, the Barrier M UV system offers a cost-effective alternative to chemical disinfection without forming harmful disinfection by-products (DBPs). The addition of the Barrier M UV system to other disinfection processes provides a multi-barrier approach, ensuring complete inactivation of all waterborne pathogens, including protozoa such as Cryptosporidium and Giardia.
The technology on which the Barrier M is based has been successfully used worldwide for years, with over 50 systems operating for various applications including swimming pools, wastewater, and fish hatcheries.
Depending on the water quality, the Barrier M systems are certified to deliver a dose of 40 mJ/cm2 (measured at the end of lamp life) for flows ranging from 40 gallons per minute (gpm) to 2 million gallons per day (mgd).
Each of the three Models - Barrier M 275, 525 and 900 - features a closed-vessel, cylindrical reaction chamber that is independently certified according to industry-leading DVGW W 294 protocol. Under this protocol, each system has been validated under a worst-case hydraulic scenario, with elbows immediately ahead and after the chamber. The compact, in-line design of the chamber minimizes piping restrictions (no curve or elbow are required), and enables flexible installation, especially in retrofit situations where space is limited. The in-line design also minimizes head loss throughout the chamber. The reaction chamber is made of stainless steel (SS) 316 Ti, which is more corrosion-resistant than standard SS such as 316 L.
Each reaction chamber is equipped with one to four medium-pressure lamps, WTL 2000, each with a nominal power of 2.3 kW. Such powerful lamps reduce the number of lamps required, minimizing footprint, head loss throughout the chamber, and lowering lamp replacement costs. Each lamp is positioned horizontally and perpendicular to the flow. To the contrary of low-pressure UV lamps, the output of medium-pressure lamps is independent of the water temperature. The doped quartz sleeves used to protect the lamps are designed to prevent the formation of nitrite ion by cutting off all emission below 240 nm.
Each reaction chamber includes an automatic mechanical cleaning system for the cleaning of the lamps’ quartz sleeves and UV sensor windows. The system consists of a Viton wiper, enclosed in a Teflon holder and supported by stainless steel plates. The system is equipped with an optical rotation detection system, which eliminates the wear and tear associated with limit switches.
The control system consists of a proprietary, specialized HPC II microcontroller. The controller is complemented by a proprietary UV-MultiSens controller for systems with multiple UV fluence rate sensors. For such systems, the UV-MultiSens controller records all individual sensor values and supplies the HPC II Controller with the lowest value.
As a standard feature, the control panel optimizes the disinfection process by automatically controlling the output of the UV lamps. By using multi-tap ballast technology, four power levels are available for running the lamps. The UV sensors, mounted in the reactor chamber, continuously monitor the UV fluence rate. Certified by the DVGW 294 Protocol, these integral sensors have been calibrated under the most stringent conditions. If the fluence rate should decrease below a level that is 3% higher than the low UV alarm level, the automatic cleaning function is activated. If, following cleaning, the fluence rate is not increased to greater than 3% above the UV alarm level, then the lamp power control function is activated and the power is increased to the next level. By adjusting the lamp output, the lamp power control feature increases the lamp life up to 9,000 hours, and minimizes power consumption.
For additional information on the Barrier M UV Disinfection System, visit www.usfwt.com/barrierM.htm. or call 800-628-0897. WW
