Soluble substrate concentrations in leachate from field scale MSW test cells.

Area of Science:

• Environmental Engineering
• Waste Management
• Water Treatment

Background:

• Landfill leachate contains non-biodegradable soluble chemical oxygen demand (COD).
• Leachate recirculation is a landfill operation strategy with potential impacts on leachate characteristics.

Purpose of the Study:

• To monitor and model the non-biodegradable soluble COD in landfill leachates.
• To compare leachate characteristics from cells operated with and without leachate recirculation.
• To evaluate the effectiveness of different mathematical models in predicting leachate composition changes.

Main Methods:

• Monitoring of non-biodegradable soluble COD in leachates from two landfill test cells (C1: no recirculation, C2: recirculation) over 1080 days.
• Fitting various mathematical models (Logistic, Gompertz) to experimental data using statistical evaluation (SSE, R-square, RMSE).
• Estimation and discussion of pollution loads and BOD/COD ratios based on fitted model parameters.

Main Results:

• The inert soluble COD fraction (f(non)) increased significantly in both cells, reaching a maximum of 0.4 by day 600 due to anaerobic conditions.
• The Logistic model provided the best fit for the control cell (C1), while the Gompertz model best described the recirculation cell (C2).
• Pollution loads and BOD/COD ratios differed between the two cells, with implications for treatment.

Conclusions:

• Leachate recirculation influences the evolution of non-biodegradable soluble COD in landfill leachates.
• Selected mathematical models can accurately predict leachate composition changes over time.
• The findings support the use of predictive models for optimizing leachate treatment processes and improving effluent quality.