Abstract:
Severe contamination of water resources including groundwater with iron (Fe) due to various
anthropogenic activities has been a major environmental problem in the industrial areas of Sri Lanka. At
present Fe rich industrial' wastewaters are mostly treated with chemical precipitation. Moreover this
technique is generally costly, depends on many intrinsic environmental parameters and requires intensive
management and long-term maintenance. Hence the use of the obnoxious weed water hyacinth
(Eichhornia crassipes (Mart.) Solms) in constructed wetlands to phytoremediate Fe rich wastewaters
seems to be an appealing option. Although several studies have documented that hyacinths are good metal
accumulating plants none of these studies have documented the effects of the nutritional status of the
plants on the phytoremediation of metal rich industrial wastewaters. Hence in this paper we report the
possible Fe removal efficiencies under different nutritional conditions of water hyacinth in batch type
constructed wetlands. This study was conducted for 15 weeks by culturing water hyacinth in 590 I
capacity fiberglass tanks under different nutrient concentrations of 2-fold (56 TN mg/l and 15.4 TP mg/l),
l-fold, 112-fold, 114-fold and lI8-fold with Fe rich industrial wastewaters containing 9.27 Fe mg/l. A
control set-up of hyacinths containing only Fe as a heavy metal but without any nutrients was also
studied. A mass balance was conducted to investigate the phytoremediation efficiencies and to determine
the different mechanisms governing Fe removal from the wastewaters
