Experimental Investigation of Phytodesalination Rate of Duckweed (Lemna Minor) in Brackish Water

Abstract

Freshwater in most communities along estuaries such as the Niger Delta region of Nigeria is difficult to access as both the
surface and groundwater around it has a higher salinity than acceptable standards. Desalination plants are on the other hand,
are energy-consuming and costly method to run. The researchers of this paper conducted an experimental investigation on
phytodesalination rate of duckweed in brackish water. Approximately 100 g of morning glory were placed in a plastic trough
containing 10 liters of brackish water (salinity 7.69 ppt) in three replicates and studied daily for 6 days. The experiment was
conducted to measure the treatment parameters of electrical conductivity (EC), pH, total dissolved solids (TDS) and salinity.
Results showed that maximum reductions of most of the water parameters were observed after 3 days of the research. The
recorded phytodesalination rates were +0.072 ppt/g/day for EC, +47.8 ppt/g/day for TDS and +0.053 ppt/g/day for salinity. Also,
the percentage reduction for EC, TDS and salinity were 16. 4 %, 16.3 % and 20.7 % respectively. The water hyacinth started
showing signs of nutrient starvation and a reduced rate of desalination after 3 days. Analysis of variance show that there was no significant difference between the control and duckweed treatment means at 95 percent confidence level of the water parameters
except for EC. This research can be optimized by continuously removing the spent duckweed and re-introducing fresh ones in 3
days intervals until salinity is within the safe threshold