title: [Use of UV rays for the disinfection of water. II. Microbiological studies of surface water].
abstract: Untreated surface water of a total bacterial count of approximately 10(4) cfu/ml was contaminated additionally with suspensions of E. coli and S. faecium, which contained about 10(6) cfu/ml. At flow rates of 7.2 m3/h, 4.0 m3/h and 2.0 m3/h the survival of bacteria as a function of exposure to radiation was measured with two different U.V.-disinfection units. In surface water, -without an additional contamination -minimum doses of radiation up to 74 mWs/cm2 were necessary to cause a reduction of 99.99% for total bacterial counts and counts of lactose-positive colonies. When suspensions of E. coli or S. faecium were added, a reduction of 99.99% for total bacterial count was attainable with minimum doses up to 71 mWs/cm2. To reduce the number of lactose-positive colonies or the number of D-streptococci to 99.99% a minimum dose up 56 mWs/cm2 or 18 mWs/cm2 was necessary.
mesh_terms: D001419:Bacteria / Q000254:growth & development / Q000528:radiation effects*; D015169:Colony Count, Microbial; D004203:Disinfection / Q000379:methods*; D004307:Dose-Response Relationship, Radiation; D004926:Escherichia coli / Q000254:growth & development / Q000528:radiation effects; D005618:Fresh Water; D013242:Sterilization / Q000379:methods*; D013291:Streptococcus / Q000254:growth & development / Q000528:radiation effects; D014466:Ultraviolet Rays; D014871:Water Microbiology
vernacular_title: Anwendung von UV-Strahlen zur Desinfektion von Wasser. II. Mitteilung: Mikrobiologische Untersuchungen in Oberflächenwasser.