Abstract:
Background: Water scarcity is a global issue and finding alternative way to meet water needs within
available resources is becoming increasingly important. Recycling grey water for non- potable uses
such as irrigation, car washing helps to decrease the demand for drinking this combats scarcity. This
study investigates the treatment of grey water using phytoremediation focusing on effect of water
hyacinth plant density and hydraulic retention time. RSM-CCD was used to optimize theses
parameters.
Methods: water hyacinth was used in this method. Its application as an excellent adsorbent for
pollutants. Removal of pollutants was also demonstrated using response surface methodology (RSM)
using Central composite design (CCD). The effects of two independent variables; plant density (0.22.3kg/m2) and hydraulic retention time (2.7-32.3 days) on the pollutant removal (PH, DO, COD, BOB,
TDS) efficiency were investigated and the process was optimized using RSM. Using central composite design (CCD), 13 experiments were carried out and the process response was modeled using a
quadratic equation as function of the variables. Results: The optimum values of the variables were found to be 2kg/mii
2 and 7 days for plant density and retention time respectively. Using RSM-CCD approach, a quadratic regression model wasgenerated to demonstrate the relationship between removal efficiency (RE) and factors of plant
density(A) and hydraulic retention time(B).
Conclusions: The significance of each of the model term was evaluated using the probability of error
value (P values) and R-sq. P-values less than 0.050 showed that the terms were significant. The model
was adequate with R2> 0.7 and P-value less than 0.050. The study concludes that phytoremediation
using water hyacinth can be a viable option for greywater recycling and reuse, effectively addressing
water scarcity.
