Leachate/domestic wastewater aerobic co-treatment: A pilot-scale study using multivariate analysis

Area of Science:

• Environmental Engineering
• Wastewater Treatment
• Bioreactor Technology

Background:

• Landfill leachate poses challenges for wastewater treatment due to its complex composition.
• Activated sludge (AS) processes are widely used but require optimization for recalcitrant pollutants.

Purpose of the Study:

• To evaluate the impact of landfill leachate addition on pilot-scale activated sludge reactor performance.
• To identify key variables affecting treatment efficiency using multivariate analysis.

Main Methods:

• Activated sludge reactors were fed domestic wastewater with varying volumetric ratios (0%, 2%, 5%) of pre-treated landfill leachate.
• Performance metrics included removal efficiencies for TSS, SCOD, DOC, and SBOM.
• Fourier transform infrared (FTIR) spectroscopy, principal component analysis (PCA), and partial least squares (PLS) were employed.

Main Results:

• A 2% leachate ratio yielded optimal removal efficiencies: 70% for TSS, 70% for SCOD, 70% for DOC, and 51% for SBOM.
• Nitrification remained high (~80%) at the 2% leachate ratio, with no significant heavy metal accumulation.
• PCA and PLS identified TAN, SCOD, DOC, and nitrification efficiency as critical performance variables.

Conclusions:

• Partial biodegradation effectively removed slowly biodegradable organic matter from leachate.
• Activated sludge treatment is feasible for leachate-containing wastewater at optimal leachate ratios (2%).
• Multivariate analysis effectively identified key factors influencing reactor performance.