Performance Evaluation of Mentha longifolia Plant for Domestic Waste water Treatment under arid climate conditions (Tamanrasset region, Algeria)

Abstract

The objective of this work is to highlight the purification performance of the Mentha longifolia plant for wastewater under a horizontal flow regime and a hot and dry (arid) climate. In this research, we made a comparison between a planted bed of Mentha longifolia and a non-planted bed (control) as well as the study of the performance of the Mentha longifolia to purify the wastewater. The study is carried out according to an experimental pilot in the urban wastewater treatment zone within the National Sanitation Office (NSO) in Tamanghasset. The experimental pilot consists of pots of capacity 130 liters filled from bottom to top on a thickness of 45 cm of gravel (15 / 25mm) of 10 cm of sand. The pot is planted with young stems of Mentha longifolia (36 stems / m2) and the other non-planted pot is taken as a control. The pots are fed by urban wastewater (18 liters / day), once a week. The water obtained after 5 days is collected in a container located under the pot. The performance information shown is for the periods from the month of January - April 2021.After four months of follow –up, we obtained the pollutant removal results with the following percentages: COD (77.74%), BOD5 (72.47%), MES (87.78%), NO3-(63.40%), NO2- (62.03%), PO43- (62.77%), E. coli (99.43%). The existence of the plant Mentha longifolia in planted beds maintains a sufficient porosity that prevents clogging. The significant reduction of pollutants and pathogenic microorganisms allows us to consider the reuse of treated water in agriculture and industry.