Effect of purified wastewater from the city of Settat (Morocco) on the quality of Lippia citriodora essential oil and infusion

Lippia citriodora is an aromatic plant largely consumed in Morocco and throughout the world. It is well-known for its use in the field of food, medicine and aroma therapy. The production of this plant is for its local uses and for export. The therapeutic activity of L. citriodora or itsextracts mainly depends on the quality of finished products. In this study, we aimed to evaluate the effect of irrigation with urban wastewater from Settat (Morocco) treated by lagoons on the composition of the essential oil, essential oil yield and physico-chemical composition infusion of L. citriodora. The soil used for the implantation is characterized. Physico-chemical analyses of well water and wastewater used for irrigation are analyzed. From the results obtained we found changes in the composition of the essential oil of a large number of constituents. After irrigation of L. citriodora by wastewater we observe changes in major compounds in the essential oil: decreased neral (from 15.29% to 14.34%) and geranial (from 15.63% to 14.75%) and increased limonene (from 23.39% to 25.86%). We deduce that wastewater has a beneficial effect in increasing the yield of essential oil. The infusion of L. citriodora prepared by the fresh and dried leaves irrigated with wastewater contains a high concentration of NH4+, Ca2+, Mg2+, and the concentration of NO2–N (mg/L) exceeds 100% of the concentration of waste water