Bioremediation of total petroleum hydrocarbons in oil sludge-polluted soil using active carbon remediator

Abstract

In this study, the effect of different sizes and weights of active carbon as a remediator was evaluated on reduction or removal of petroleum hydrocarbons of a soil polluted by petroleum sludge. The present pilot study was conducted as a split plot in time experiment based on a completely randomized design with three replicates under laboratory conditions for period of 60 days. The experimental treatments included active carbon weights and sizes of 100 g and 0.3 mm (W100S0.3), 100 g and 1.5 mm (W100S1.5), 100 g and 4 mm (W100S4), 150 g and 0.3 mm (W150S0.3), 150 g and 1.5 mm (W150S1.5), 150 g and 4 mm (W150S4) and control (C). Total petroleum hydrocarbon (TPH) and microbial respiration were measured each ten days. The results showed that concentration of TPH decreased with increasing active carbon weight and size. The highest and lowest TPH concentration at all 10-day intervals was associated with control and W150S0.3 treatments. Decreased TPH was accompanied by increased microbial respiration. In general, TPH biodegradation constant (K) increased and half-life times (T1/2) decreased by increasing active carbon application with smaller sizes. The lowest value for TPH biodegradation percentage was associated with W100S4 and W100S1.5 treatments. Active carbon treatments of W150S0.3 and W150S1.5 led the best TPH biodegradation in petroleum sludge-polluted soil. Therefore, active carbon remediator may be applied as a low-cost, efficient and environment-friendly strategy for remediation of petroleum pollution in soil.