Review on polycyclic aromatic hydrocarbons (PAHs) migration from wastewater

Area of Science:

• Environmental Science
• Chemical Engineering
• Water Treatment Technologies

Background:

• Growing global population and industrialization increase wastewater volumes, necessitating advanced treatment for contaminants like polycyclic aromatic hydrocarbons (PAHs).
• PAHs are highly carcinogenic and pose significant risks to human health and aquatic ecosystems, demanding effective removal strategies from wastewater.

Purpose of the Study:

• To review and assess various available treatment methods for polycyclic aromatic hydrocarbons (PAHs) in wastewater.
• To explain the principles, remediation mechanisms, and recent advancements in PAHs removal practices.
• To provide comprehensive information on PAHs, including sources, toxicity, and treatment effectiveness.

Main Methods:

• Review of existing literature on PAHs sources, properties, toxicity, and conventional treatment procedures.
• Detailed assessment of advanced oxidation processes (AOPs) and catalytic oxidation processes for PAHs removal.
• Performance evaluation of different techniques, focusing on removal efficiencies for various PAH ring structures.

Main Results:

• Advanced oxidation processes (AOPs) coupled with catalysts demonstrate high efficiency, achieving up to 99% reduction for 5- or 6-ring PAHs and 79% for 3-ring PAHs with a titanium catalyst.
• Conventional secondary treatment in municipal wastewater treatment plants (MWTPs) shows removal efficiencies between 81.1-92.9%.
• AOPs offer a broad removal range (32-99.3%) and are particularly effective when enhanced with catalysts, suitable for both low and high ring PAHs.

Conclusions:

• Advanced oxidation processes (AOPs) and catalytic oxidation processes are the most promising techniques for effective PAHs removal from wastewater.
• Combining AOPs with catalysts presents a highly competent design for treating PAHs in wastewater, offering superior removal rates and broader applicability.
• Effective PAHs treatment is crucial for mitigating environmental pollution and protecting public health and aquatic ecosystems.