Evaluation of Biochar Efficiency on Absorption and Degradation of Crude Oil in Contaminated Wetland Soils.

Biochar, a pyrolysis product of biomass wastes, has been used to enhance soil fertility and carbon sequestration. It is also regarded as an ecofriendly absorbent for its porous structure. The objective of the present study is to assess the effect of four different types of biochars on remediation of oil contaminated coastal wetland soils. Different treatments of biochars produced from biomass wastes of sugarcane residues, pine wood, rice straws, and chicken litter were incubated with crude oil-contaminated wetland soils of two different organic carbon contents and under sufficient N levels in a series of microcosm experiments. Gas concentration in headspace of incubator jars was monitored periodically to assess the respiration of treated oil-contaminated soils. At selected time intervals, the biochar-treated oil-contaminated soils were extracted and analyzed for total petroleum hydrocarbons (TPH) using gas chromatography/mass spectroscopy following solvent extraction with dichloromethane and hexane. Preliminary data indicates significant differences of oil degradation between low and high carbon soils. Different biochars showed varying efficiency in reducing the presence of TPH. The results suggest that biochar can be used for remediation of oil contaminated wetland soils.