Controlling coliform bacteria by using ultraviolet light

The objective of this study was to determine the possibility of killing contaminating bacteria by use of ultraviolet light over coliforme fecal population present in water. Calibration of the equipment was achieved by means of using in vitro contaminated water with known concentrations. The relationship between applied UV doses and number of faeces coliformes present in water after treatments were analysed. Water samples at three points of Chillan River, Chile, Fl Saque, Nebuco, and Vista Bella bridges were taken. The highest amount of microorganism was found in samples at the Vista Bella bridge and the lowest in samples at El Saque bridge. The samples were treated with three ultraviolet light doses: 0.155, 0.224, 0.376 J.cm(-2). With highest microorganism population decline, but the differences in the result of the treatment was not significant. Consequently the best dose fbr water disinfecting for further use in irrigation of vegetable and fruits grow level of soil is 0.155 J.cm(-2).