Assessment of Phytoremediation in removing selected heavy metals from wet market wastewater

Abstract

In Malaysia, wet market wastewaters are discharged directly into receiving water without any treatment. The contaminated wastewater may affect both of human and aquatic life if not treated properly. Thus, this study was conducted to assess the potential of phytoremediation in removing the heavy metals, which is one of contaminants in wet market wastewater by using two species of floating plants, Eichhornia crassipes (water hyacinth) and Lemna minor (duckweed). The wastewater source for this study was collected from Pasar Borong Kangar. The characteristics of wet market wastewater were determined. The pH, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solid (TSS), zinc (Zn) and iron (Fe) values of the wastewater are 6.6, 96 mg/L, 475 mg/L, 119 mg/L, 0.726 mg/L and 1.528 mg/L, respectively. In this study, three containers were filled up by 3L of wastewater, the first and second container was planted by water hyacinth and duckweed, respectively while, the third container was served as control. The wastewater sample was collected from each containers on 0th, 2nd, 4th, 6th, 8th and 10th day of treatment for heavy metals analysis. At the end of experiment, all of plants were harvested, dried and digested to determine the heavy metals uptake by plants. Based on experimental results, 99.57% of Zn and 97.91% of Fe were removed by duckweed while, 98.34% of Zn and 97.05% of Fe were removed by water hyacinth. The relative growth of duckweed and water hyacinth recorded are 1.05 and 0.73, respectively. Bioconcentration Factor of Zn and Fe for duckweed are 100 and 98, respectively while for water hyacinth are 98 and 97, respectively. Translocation Factor of Zn and Fe for duckweed are 0.06 and 0.02, respectively while for water hyacinth are 0.17 and 0.41, respectively. Overall, duckweed is as a better floating plant in removing Zn and Fe from wet market wastewater compared to water hyacinth.