Potential of Duckweed (Lemna minor) for the Phytoremediation of Landfill Leachate

Abstract

Phytoextraction of zinc, copper, lead, iron, and nickel from landfill leachate by duckweed (L. minor) was investigated every 3 days over a period of 2 weeks. Bioconcentration factor and removal efficiency were also calculated. Results of this study proved that L. minor significantly reduced the concentration of heavy metals in landfill leachate. Removal efficiency of L. minor, for all the metals, from landfill leachate was more than 70% with the maximum value for copper (91%). Reduction in chemical oxygen demand (COD) and biological oxygen demand (BOD) was observed by 39% and 47%, respectively. However, other physiochemical parameters like pH, total suspended solids, (TSS) and total dissolved solids (TDS) were reduced by 13%, 33%, and 41%, respectively. The value of bioconcentration factor (BCF) was less than 1 with the maximum figure for copper (0.84) and lead (0.81), showing that the plant is a moderate accumulator for these heavy metals. Duckweed (L. minor) appeared as a sustainable alternative candidate and is recommended for the treatment of landfill leachate waste water contaminants.

Application of Floating Aquatic Plants in Phytoremediation of Heavy Metals Polluted Water: A Review

“…These are the plants with floating leaves and submerged roots. Some of the free-floating aquatic plants are well recognized for their capability to eliminate the metals from the contaminated environment: water hyacinth (Eichhornia crassipes) [128], water ferns (Salvinia minima) [129], duckweeds (Lemna minor, Spirodelaintermedia), [130,131], water lettuce (Pistiastratoites), [132], water cress (Nasturtium officinale) [133]. The potential of these free floating aquatic plant for the elimination of heavy metals is comprehensively studied in different studies [99,134,135].…”

“…The capability of duckweed plant to develop in polluted site with tremendous variation in pH, temperature, nutrient level makes them effective for use in phytoremediation [207]. Duckweed can eliminate a vast variety of different heavy metals, inorganic and organic contaminants, pesticides, nutrients arise from agricultural runoff, sewage, industrial and domestic wastewater [131,138,208]. Duckweed can easily inhibit the growth of algae and fungi in different ponds because it has the ability to cover the ponds due to its widespread high growth rate.…”

“…Removal of the nutrient with the application of duckweed biomass will help to upgrade the quality of water and degradation of water ecology. Duckweed shows higher removal aptitude for chemical oxygen demand (COD), biological oxygen demand (BOD), total nitrogen (TN), total suspended solid (TSS) and NH 3 -N from wastewater under favorable environmental circumstances [131,207]. Much higher elimination of different HMs such as As, Cr, Cu, Zn, Ag, Hg, Pb and Cd has been done through different species of duck weed including L. minor, L. Trisulca and L. gibba from wastewater [4,210,211] S. polyrhiza, L. gibba and L. minor examined for their remediation efficiency of boron, arsenic, and uranium.…”

Hybrid Phytoremediation: an Ultimate Bio-Solution for Leachate

“…Additionally, further purification was assured by the assimilation of duckweed. Mackenzie et al, 2003;Daud et al, 2018 have researched and reported the potential of the aforementioned species individually can reduce the total metal concentration levels up to 70% associated with a BOD, COD, pH, TSS, and TDS removal of around 45%, 40%, 15%, 35%, and 40% respectively through the phytoremediation mechanism, which is good enough to stand alone. Despite, the present research work has recorded a significantly lower level of efficacy (i.e.…”

“…The same mechanism is replicated by the duckweed as well. The harvesting technique is also quite simple and inexpensive in the case of smaller constructed wetland system (Mackenzie et al, 2003;Daud et al, 2018). Approximately 70% of the atmospheric oxygen gets generated due to the autotrophic activity of the microalgae.…”