Enhancing Oil Spill Phytoremediation: A Comparative Study of Biochar, Compost and Organic Manure on Barnyard Grass Efficiency

Abstract

Crude oil spills remain a significant environmental hazard associated with petroleum exploration and transportation. Conventional cleanup methods including the use of dispersants and other chemicals, though effective in reducing oil concentration, often leave lasting negative impacts on soil and aquatic ecosystems. In contrast, phytoremediation offers a sustainable, eco- friendly, and cost-effective solution. It involves using specific plants to degrade, absorb, or contain contaminants in soil or water. This study focuses on enhancing the phytoremediation capacity of barnyard grass (Echinochloa crus-galli), a plant known for its resilience in crude oil-contaminated environments. The research investigates the comparative impact of three organic soil amendments which are biochar, compost, and organic manure on the efficiency of barnyard grass in remediating oil- polluted soil. The specific parameters monitored included soil pH, electrical conductivity, resistivity, total dissolved solids (TDS), and salinity which are factors that reflect the extent of soil contamination and recovery. A total of four treatment groups were established under controlled conditions: one untreated control and three experimental groups each amended with 2% by weight of either biochar, compost, or manure into 15 kg of crude oil-contaminated soil. Each treatment was planted with barnyard grass and observed over an 8-week period. Soil analyses were conducted weekly using consistent measurement procedures to track changes in soil properties indicative of remediation progress. The results demonstrated clear trends in phytoremediation performance across the different treatments. Compost-amended soils showed the most rapid and sustained improvements in all measured parameters, suggesting a more effective breakdown of hydrocarbons and enhancement of plant-microbe interactions. Biochar and manure also supported remediation, though their effects were less consistent and exhibited slower response times. Overall, the study highlights the superior performance of compost in aiding barnyard grass phytoremediation and underscores its promise as a cost-effective, sustainable approach to crude oil remediation in polluted environments.