Phytoremediation by mangrove trees: Experimental studies and model development

[Display omitted] •A phytoremediation system for extraction of Cr by mangrove trees was constructed.•The operation of the system depends on soil type, Cr load and fertilizer.•A mathematical model was developed capturing the nonlinear dynamics of the system.•Suitable operation modes were derived both from experiments and simulations. Phytoremediation studies were performed for the removal of chromium by young mangrove species Rhizophora apiculata. A pilot remediation system was constructed in a greenhouse consisting of aquaria with mangrove trees, which were flooded twice a day to simulate natural conditions of mangrove swamps. The effects of chromium loads, soil environment and fertilizer on the remediation process were studied in a three factorial experiment. From the obtained data, a mathematical model was derived capable of simulating the operation of a phytoremediation system in dependence on the control variables including number and size of the trees, soil type and chromium load. The model was applied to assess the performance of the system under different operation modes. The results obtained both by the experiments and simulation studies show that bioextraction of chromium using young mangrove trees is feasible. The inhibition of plant growth at high chromium concentrations causes a complex dynamic behavior of the system. Therefore, a careful choice of the control variables is necessary to ensure optimal performance of the system.