الفهرس 
ACKNOWLEDGMENTOnly 14 pages are availabe for public view
 |  | from | 143 |  |  |
| | | from | 143 | | |
Abstract
Heavy metals are toxic substrates that cause many human diseases. Their removal is required before reuse of treated wastewater in agricultural. Constructed wetlands become known systems that use different types of plants to extract contaminants from the environment because they are affordable, reliable, simple in design and operation, and offer an environmental-friendly approach. This study aims to remove heavy metals and nutrients from secondary treated wastewater using aquatic plants.
Batch experiments using two types of aquatic plants namedEchinochloa pyramidalis, Ludwigia stolonifera planted in association and individually. Reference experiments without aquatic plants were carried out.All experiments werefor 10 days retention time for the removal of cadmium (Cd), nickel (Ni) and lead (Pb) from secondary treated wastewater. Higher removal efficiency of Cd, and Pb (75.53% and 98.31%) at concentration of 5mg/l when planted together than that of individual growth was obtained, while L.stoloniferaplant showed the highest removal efficiency of Ni (49.40%) at concentration of 20mg/l. A positive relationship was observed between detention time and heavy metals removalefficiency. L.stoloniferaplant showed a greater absorption capability than E. pyramidalisplantfor all tested heavy metal types except for Pb. Electrical conductivity (EC), pH values, total dissolved solids (TDS), nitrite – nitrogen (NO2 – N), nitrate – nitrogen (NO3 – N), orthophosphate (PO4 – P), and total phosphorus (TP) were measured at the beginning and end of experiments to assess the effect ofE. pyramidalis and L. stolonifera plants in treating wastewater. E. pyramidalis showed the higher removal efficiency than L. stolonifera for all measured nutrients except (NO2 – N). It is concluded that both E. pyramidalis and L. stolonifera have high capabilities to remove heavy metals and nutrients (N and P) directly from treated wastewater. It is concluded also that the maximum removal efficiency of heavy metal was at a plant density of 100% (75.53% for Cd, 36.44% for Ni, and 98.31% for Pb), while the minimum was at a plant density of 20% (36.53% for Cd, 14.13% for Ni, and 86.96% for Pb). Some sewage treatment plants in Sohag Governorate, such as west Sohag, El-cola, and west Gerga were evaluated.