Evaluation of the Efficiency of a UV Plant for Drinking Water Disinfection

Abstract

The effective UV-dose in a UV-reactor depends on the transmission and the flow rate of the water being irradiated as well as on the design of the plant and the hydraulic behavior. Since there is no possibility for a direct and simple dose measurement in such a system, it is necessary to develop a testing procedure which estimates the hygienic safety of such a plant. B. subtilis (ATCC 6633) spores were suspended in potable water and irradiated in a commercially available drinking water UV plant with varying flows (0.5 to 7.5 m3/h) and transmission (3 to 80 %; thickness 10 cm). Sodium thiosulfate and adenosine were used as transmission reducing substances. Because of the known UV sensitivity of the spores it was possible to calculate the effective dose in the reactor as space radiant exposure for each test. The data resulted in an individual diagram of efficiency. It was shown that this testing procedure is suitable for the evaluation of the disinfection capacity of UV plants and the estimation of the field of application depending upon transmission and flow rate of the water being irradiated.

Inactivation of E. coli, B. subtilis spores, and MS2, T4, and T7 phage using UV/H2O2 advanced oxidation

“…Bacteria: (a) B. subtilis spores (ATCC 6633) were produced by a liquid cultivation technique and obtained freeze-dried [10]. Working solution was prepared by resuspending the spores in water.…”

“…Working solution was prepared by resuspending the spores in water. Spores were enumerated by pour plate technique with PC-Agar (Oxoid CM 325), at 37 • C for two days, as colony forming units (CFU) per ml [10]. (b) E. coli B (ATCC 11303) was cultivated using the recommended tryptone based broth in incubator at 37 • C shaking for 4 h till the concentration was 10 8 cells/ml.…”

Disinfection of Drinking Water by UV Irradiation: Basic Principles - Specific Requirements - International Implementations

“…This has been carried out by three international organizations: The use of biodosimetry to evaluate the disinfection capacity of commercial UV disinfection plants is common to all three UV disinfection standards and testing protocols. Biodosimetry is included in a validation test, which is performed as a full scale test of a (commercial) UV disinfection plant either at a test stand or on site in the water work (Sommer et al, 1993).…”

Die Typprüfung Von Anlagen Zur Desinfektion Von Trinkwasser Mittels Uv-Strahlung

“…Mehrere Parameter beeinflussen die Desinfektionswirksamkeit der Anlagen, die wichtigsten sind: Die Strahlungsleistung des Strahlers bei 253,7 nm, der Durchfluss des Wassers, die UV-Durchlässigkeit des Wassers, die hydraulischen Verhältnisse innerhalb der Desinfektionsanlage, die Reflexion der UV-Strahlung an den Innenwänden des Reaktors usw. und Sommer et al, 1997 (Sommer and Cabaj, 1993;Qualls and Johnson, 1983), also von bezüglich ihrer UV-Empfindlichkeit kalibrierten Mikroorganismen, als die einzige mögliche Methode. Die Überlebensfunktion g(Ho) von Mikroorganismen deren Inaktivierungskurven bei niedrigen Fluenzen einen flachen Verlauf zeigen (Schulter) läßt sich mit Hilfe der Funktion …”