Mature landfill leachate utilization using a cost-effective hybrid method

Area of Science:

• Environmental Engineering
• Waste Management
• Biotechnology

Background:

• Mature landfill leachate poses significant environmental challenges due to its complex composition.
• Effective treatment methods are crucial for sustainable waste management and resource recovery.
• Hydrodynamic cavitation is an emerging pretreatment technology for recalcitrant wastewater.

Purpose of the Study:

• To evaluate the co-digestion of sewage sludge and hydrodynamically cavitated mature landfill leachate.
• To assess the impact of this combined treatment on organic removal, biogas yield, kinetics, and digestate quality.
• To determine the energy efficiency and safety of the proposed two-stage treatment process.

Main Methods:

• Co-digestion experiments were conducted using sewage sludge and pretreated landfill leachate (5% v/v) at a 20-day hydraulic retention time.
• Process efficiency was analyzed through measurements of organic removal, biogas production, and digestate characteristics.
• Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) was employed to identify potential toxic byproducts.

Main Results:

• Co-digestion significantly improved process kinetics and increased biogas production and yields compared to control groups.
• The digestate quality was enhanced, indicating better stabilization and nutrient availability.
• FTIR-PAS analysis suggested that no new toxic compounds were generated during the co-digestion process.

Conclusions:

• The two-stage treatment involving hydrodynamic cavitation pretreatment of leachate followed by co-digestion with sewage sludge is highly effective.
• This method offers a safe, cost-effective, and environmentally sound approach for managing mature landfill leachate and sewage sludge.
• The process promotes resource recovery through enhanced biogas generation and improved digestate quality.