Comparing the effect of applying different types of amendments on carbon emissions and kinetics of degrading total petroleum hydrocarbons in artificial petroleum-contaminated soil.

Contamination by spent engine oil represents a significant global environmental challenge as it poses a major hazard to human health, animals, plants, microorganisms, the soil ecosystem, and aquatic ecosystems. This study assumes that some amendments differ significantly in their ability to degrade petroleum hydrocarbons. Therefore, this incubation study was conducted to investigate the effect of different types of inorganic and organic amendments (zeolite, bone char, banana leaves biochar, and wood chips biochar) on carbon emissions (CO₂-C) and the kinetics of total petroleum hydrocarbons (TPHC) degradation in artificial petroleum-contaminated soil. These amendments were added to the soil under study at a dose of 3% (w/w). At the end of the incubation period, applying zeolite, bone char, banana leaves biochar, and wood chips biochar to artificial petroleum-contaminated soil significantly reduced cumulative CO₂-C emissions compared to the control. The banana leaves biochar significantly decreased TPHC concentrations in artificial petroleum-contaminated soil compared to the control treatment. At the end of the incubation period, adding banana leaves biochar to the soil showed high degradation efficiencies of TPHC which was 36% higher than soil before incubation. The effectiveness of applying amendments used in this experiment on the degradation of TPHC increase was in the order of banana leaves biochar > bone char > wood chips biochar > control > zeolite. The second-order model described the kinetics of total petroleum hydrocarbons better than the first-order model. Banana leaves biochar added to the soil resulted in a significant increase in the degradation rate constant of total petroleum hydrocarbons (k₂) compared with the control. A higher k₂ value indicates that TPHC degrades more rapidly. The half-life of TPHC degradation in the soil was decreased significantly by adding banana leaves biochar. According to the second-order equation, the half-lives of control, zeolite, bone char, banana leaves biochar, and wood chips biochar were 4.0, 5.3, 2.7, 1.0, and 3.6 years, respectively. The banana leaves biochar amendment might be cheaper and more environmentally friendly than other organic amendments because it has the high potential for carbon sequestration and remediate petroleum-contaminated soil, which would increase the sustainable use of petroleum-contaminated soil leading to preserving the environment.