Improved Bioremediation of Diesel-Contaminated Soils Using Stabilized Poultry Manure

The increase in environmental pollution caused by inadequate anthropogenic practices is emerging as a global threat to human health and ecosystems. Addressing this issue is crucial, and bioremediation stands out as a sustainable solution for remediating contaminated soils. This study evaluates the feasibility of bioremediation to mitigate soil contamination by petroleum hydrocarbons using laying hen manure as a biostimulating agent, in the forms of manure stabilized by simple drying and compost from fresh manure. The specific objectives included analyzing the interaction between manure and contaminants, evaluating the influence of physicochemical and microbiological variables, comparing the efficiency of different manure proportions, and assessing contaminant reduction rates. Physicochemical and biological monitoring and statistical analysis were conducted. The results indicate that the treatment with stabilized manure significantly differed from the control sample, achieving up to 98% reduction in total petroleum hydrocarbons concentrations within 60 days and microorganism populations of around 10⁷ CFU/mL. In contrast, the treatment with compost did not show significant differences from the control. Furthermore, while both treatments increased microbial populations, only the compost treatments maintained non-toxic conditions for soybean seed germination and root elongation, highlighting its potential for agricultural applications post-remediation. Stabilized poultry manure, though effective in total petroleum hydrocarbons degradation, resulted in soil toxicity due to high salinity and potassium levels, necessitating careful management. Its combined application with sawdust is recommended to improve soil structure and counteract compaction. These findings underscore the effectiveness of stabilized manure in accelerating bioremediation and the potential of compost to enhance soil health, suggesting tailored applications depending on specific remediation goals.