Optimization of Arsenic Phytoremediation by Ludwigia octovalvis in Pilot Reed Bed System using Response Surface Methodology

Abstract

The optimization of Arsenic (As) phytoremediation by L. octovalvis was conducted in reed bed system. Factors for optimization were As loading (5, 22 and 39 mg/kg), retention time (14, 28 and 42 day) and flow of aeration (0, 1 and 2 L/min). Performance evaluation was based upon six observations; As in L. octovalvis, TF, percentages of translocation, As uptake effectiveness by L. octovalvis, bioavailable As and total extractable As removal in As-spiked sand. Based on the response surface methodology using Box-Behnken design, the optimization condition for As phytoremediation occurred at As concentration of 39 mg/kg on Day 42 with 0.22 L/min flow of aeration. The optimum condition model gives the removal of bioavailable and total extractable As at 94.8 and 72.6 % respectively. The other responses were As in L. octovalvis (1157.87 mg/kg), TF (1.62), percentages of translocation (46 %) and effectiveness of uptake As by L. octovalvis (17.1 %). By comparing the model with a validation run, the optimization condition error for all responses was below 10 %. Factor such as As loading, retention time and flow of aeration could affect the performance of As phytoremediation by L. octovalvis.