Phytopurifying activity of Salvia officinalis L. from Tunisia

The sage (Salvia officinalis L.) is an annual and biennial plant of Mediterranean origin from the Lamiaceae family. It's a valuable medicinal plant, which is widely used in traditional medicine in world and in Tunisia; this species is very rich in active biological compounds. The objective of this study was to determine the phyto-purifying activity of sage essential, fixed oil and ethanolic extracts in an extensive wastewater purification system of Tunisian national sanitation office. We have measured the physico-chemical parameters of wastewater treated with sage oils and extracts. Then, we have carried out a bacteriological analysis of this wastewater. Our results showed that pH values measured following treatment with sage essential oil gave a pH close to neutral. Therefore, this water can be used for irrigation. In addition, the sage leaves and stems have a considerable effect on the salinity and caused a very remarkable increase in electrical conductivity of the wastewater, the measure of elimination rate demonstrated the effectiveness of sage extracts in eliminating all the microorganisms existing in wastewater. In fact, sage essential oil has the greatest effectiveness in reducing the chemical oxygen demand of the wastewater and we have noticed that a decrease in chemical oxygen demand of microorganisms existing in the wastewater was necessarily accompanied by a decrease in biological oxygen demand. Therefore, sage leaves and stems were more effective in reducing suspended matter existing in wastewater.