EFFICIENCY OF SOME PLANTS IN REMOVING HEAVY METALS FROM WETLAND EFFLUENT

Abstract

Reuse properly treated wastewater for irrigation is compulsory option, particularly in arid and semi-arid areas, as it represents an additional, reliable source of water needed for agriculture. Constructed wetland was established (30 x 34m) as a research wastewater treatment and reuse in cultivating different plant species, at Sadat City, Egypt (90km in the western desert of Egypt). Different water reads were cultivated as biological filters (Phragmites australis, Cyperus papyrus, Typhe Sp., Cana indica). Plant samples were collected twice a year, then dried and sent for analyses with special reference to heavy metals content. All plants grown in gravel wetland were harvested, bio-mass production of each plant was determined as fresh weight. The aim of this study is to investigate the efficiency of these plants in heavy metal removal from the treated wastewater. Heavy metals considered the most hazardous problem in the wastewater beside the toxic organic molecules particularly when industrial wastewater is involved. The obtained results indicated that, most successful plants are Cattails, Papyrus and Phragmites. The bio-mass production was 21.4, 19.9 and 3.7 kg/m2 of gravel surface respectively, meanwhile the uptake of these plants from heavy metals were quite significant. Cattails was the most effective plant in both bio-mass production and heavy metals up take, however papyrus produced good amounts of bio-mass and removed much less heavy metals while phragmited produced less bio-mass but removed more iron and medium amounts of cobalt, lead, zinc, copper and manganese. Bio-mass of these plants can be of economic value in market opportunities. Usage of the above mentioned plants will be discussed.