Abstract

Polycyclic aromatic hydrocarbons (PAHs) are hazardous organic pollutants commonly found in sewage sludge, posing risks to the environment and human health. Ex-situ bioremediation techniques provide a promising solution for the removal and degradation of PAHs in sewage sludge. This abstract presents a summary of the methods and challenges associated with ex-situ bioremediation of PAHs in sewage sludge.

Various ex-situ bioremediation techniques, including composting, landfarming, bioreactors, and phytoremediation, have been employed to treat PAH-contaminated sewage sludge. Composting utilizes microorganisms to degrade PAHs during the natural decomposition of organic matter, while landfarming relies on indigenous microorganisms in soil to facilitate PAH degradation. Bioreactors offer controlled environments for the biodegradation of PAHs, with different types suitable for aerobic, anaerobic, or hybrid processes. Phytoremediation involves the use of plants to uptake and break down PAHs in sewage sludge. However, several challenges must be addressed for effective exsitu bioremediation. The complexity of PAH mixtures, variations in sludge characteristics, and inhibitory substances can impact degradation rates. Optimization of environmental factors, microbial consortia selection, and the use of genetically engineered microorganisms hold promise for improving PAH removal efficiency. Integration of different bioremediation techniques and monitoring the fate and transport of PAHs post-treatment are crucial for long-term effectiveness and risk mitigation.