Effect of Ludwigia octovalvis biomass ratio on hydrocarbon phytotoxicity

Phytoremediation, an environmentally friendly approach that uses plants to break down and remove contaminants from the environment, as a viable treatment for the removal of hydrocarbons. It has the potential to be more efficient, less expensive, and more ecologically friendly than the conventional treatment. This study aimed to determine the phytoremediation capability of native plant, Ludwigia octovalvis, by varying the biomass of plants to 100 % petroleum sludge with 33,368 mg/kg total petroleum hydrocarbon (TPH). After 30 days of treatment, a different biomass of L. octovalvis (0.106 g of plants/g of TPH, 0.159 g of plants/g of TPH and 0.212 g of plants/g of TPH) was exposed to 30 kg petroleum sludge. Two treatments with and without plants were tested to investigate if there is an effect of plant number on the removal of TPH in sludge. Results revealed that exposure to real petroleum sludge had removal efficiencies of 45.2 % (106.2 g biomass of plants), 30.1 % (159.3 g biomass of plants) and 40.0 % (212.4 g biomass of plants). Relative growth rate (RGR) analysis showed that as the biomass of plants increased, the concentration of pollutant decreased. Scanning electron microscopic analysis showed that plant root had increasing C percentage in the root part compared to stem. The plant biomass of 106.2 g had the highest TPH removal efficiency in 30 kg petroleum sludge, and the ratio of plant biomass to TPH mass was 0.106 g/g. The results could be used as a basis for other research on scaling up phytoremediation.