Articles
THE USE OF CATTAILS (TYPHA) AND COMPOST FOR REMOVING HEAVY METALS FROM SIMULATED WASTEWATER
If the reclaimed water is going to be used for irrigation of crops, it is important that the concentration of heavy metals is kept as low as possible.
This paper describes a preliminary effort to determine the role of compost as the growing media (in this case produced from chicken waste and paper pulp sludge), and one of the most common plants in wetlands the cattail (Typha) in removing heavy metals from simulated wastewater.
Six solutions were used, with three different concentrations of five heavy metals (Cd, Cu, Ni, Pb and Zn) at two different pH values (5.5 and 7.0). For each of the six treatments and the control (blank), which was irrigated with tap water, six plants were used.
The metals were added as a nitrate compound thought to be easily accumulated by the plants.
Plants were grown in individual 2.5 l pots in a greenhouse (10 hours lighting, 12°C minimum). The irrigation with the metal solutions lasted for four weeks.
At the end of this period the plants were harvested dried and weighed.
Metals were extracted from the plants with nitric acid and quantified using an atomic absorption spectrophotometer.
The results obtained suggest that the plants have a minor part in the removal of heavy metals.