Biochar amendment as a remediation strategy for surface soils impacted by crude oil

Area of Science:

• Environmental Science
• Soil Science
• Bioremediation

Background:

• Petroleum hydrocarbon contamination poses significant environmental risks.
• Effective bioremediation strategies are crucial for restoring impacted soils.
• Organic amendments can influence microbial activity and pollutant degradation.

Purpose of the Study:

• To evaluate the impact of biochar as an organic bulking agent on petroleum hydrocarbon biodegradation.
• To compare the efficacy of different biochar types (walnut shell vs. ponderosa pine) in crude oil-contaminated soils.
• To assess the influence of biochar on total petroleum hydrocarbons (TPH) degradation rates.

Main Methods:

• Batch laboratory experiments were conducted using crude oil-impacted soils.
• Soils were amended with fertilizer and biochars derived from walnut shells or ponderosa pine wood.
• Incubation at 25°C with consistent moisture levels (75% MWHC) and regular stirring.
• Total petroleum hydrocarbons (TPH) were measured over time to determine biodegradation rates.

Main Results:

• Addition of fertilizer and biochar generally increased TPH biodegradation rates.
• Ponderosa pine wood biochar significantly enhanced TPH biodegradation.
• Walnut shell biochar exhibited inhibitory effects on TPH biodegradation.
• The positive impact of biochar was more significant in soils with lighter hydrocarbons.

Conclusions:

• Certain biochars, particularly ponderosa pine, can enhance bioremediation of petroleum-contaminated soils when combined with fertilizer.
• Biochar type is critical, as some can be inhibitory (e.g., walnut shell).
• This approach offers a potentially low-technology, eco-friendly strategy for soil remediation.