A Fiber Optic Sensor Integrated with Fuzzy Similarity Analysis to Evaluate Hydrocarbon Pollutant in Water

One of the main environmental problem is related to amount and quality of water at our disposal. Water is a natural resource, not industrially reproducible, and the quality issue is a theme absolutely important especially for foodstu®s production and for resulting environmental impacts. Many developed countries have adopted law that call for constant monitoring of water quality. These procedures impose controls both in terms of quality | the possible presence of contaminants | and quantitative | how much they are present (percentage). Monitoring is an essential step in order to implement procedure for puri¯cation from contaminants. A possible tool of detection is constituted by employment of optical ¯bers. Their building features | do not contain electronic part and are geometrically versatile versatility so ¯ber sensor can be con¯gured in arbitrary shapes | allow an optimal use in liquid environments [2]. By means of a sensor, principally formed of a transmitter and a receiver both in optical ¯ber, a sample containing water with micro particles of pollutant is put through a light source; the receiver is used to evaluate the absorption of light at di®erent frequencies. This research proposes a new methodology designed to detect and classify micro particles of hydrocarbons, type C14 C40, in water. In particular, the obtained signals are subjected to a fuzzy similarity analysis [3] in order to detect the presence of micro pollution and classify the percentage. A sensor integrated with fuzzy similarity analysis represent an useful tool: easy to use and without implementation of complex procedure. Any technological production would also allow an "in situ" analysis.