IDENTIFICATION DE PLANTES EPURATRICES LOCALES ET LEUR UTILISATION DANS L’EPURATION DES EAUX USEES DE LA REGION D’EL OUED

Abstract

The objective of this study is to highlight the treatment performance of plants :Phragmite australs, Typha latifolia and Juncus effesus vis-a-vis wastewater treatment in a subsurface horizontal flow. This studyincluded a comparison between planted basins, as each basin contains a sample of plants, and a non-planted basin taken as a witness. The study was conducted through an experimental model in the treatment of urbansewage area at the national office of sanitation of EL oued wilaya of EL oued in Algeria which is considered as a semi arid zone. This model consists of circular basins 80L of capacity filled from the bottom up by a 45 cm thick gravel (15/25) mm , 20 cm of sand,and 5cm of mud.The basin wasfeeded by urban wastewater is performed after preliminary treatment (physicaltherapy) at 30L/day and once/week. The water obtained in the basin after a period of 5 days is collected througha container placed under the basin where the study lasted one year (January to December 2014). Wearrived to remove pollutants by the following rates: The COD : (76,08% for Phragmite australs, 74, 97% for Juncus effusus and 73,8% for Typha latifolia). The BOD5 : (91,3% Phragmite australs for Juncus effusus, 92,2% and 95,3% for Typha latifolia). The TSS : (97,17% for Typha latifolia, for Juncus effusus, 95,13% Phragmite australs and for 93,05%).NH4 + :It was average 99% for three plants. NO2 - : content was decreasedat a rate of 87,57for Typha latifolia89,13% for Juncus effusus and89,13% for Phragmite australs. NO3 - : 86, 7%for Typha latifolia 81,5 for Juncus effusus, and 87,20% for Phragmite australs . PO4 3- :Was foundit deband between (78.88%-83.81% -%80.69). We also found that the plants are able to remove organic pollutants (bacteriological) by 99%. The plant Typha latifolia has given better results compared to the other two plants on its power to remove organic pollutants and orthophosphates PO4 -3. In conclusion we can infer that the decrease of pollutants and harmful baciles allows us to focus on reusingtreated wastewater in agriculture and industry.