Factors Affecting the Leachate Water Volume from Landfills

In landfills, there are two main sources of leachate generation: external and internal factors. External factors include groundwater infiltration, rainfall, and surface runoff, while internal factors involve the moisture originally present in the waste, which is released due to compaction, and the water produced from the anaerobic decomposition of organic components in the waste. Therefore, the leachate production rate varies significantly and is influenced by factors such as rainfall, seasons, exposed land area, and the method of landfilling.

Generally, the highest leachate production occurs in summer, accounting for about 50% of the annual total, because of abundant rainfall, with leachate primarily coming from the infiltration of rainwater into solid waste. Landfills with a surface stacking layout tend to have a much larger exposed area compared to deep pit-type landfills, leading to a significant increase in leachate production. This causes the leachate treatment equipment to operate under high load during the rainy season and remain idle during dry periods, resulting in intermittent operation and potential strain on the equipment.

Where:

Q = Leachate production rate (m³/d)

I = Average daily rainfall over multiple years (mm/d)

A₁ = Area of the operational unit watershed (m²)

C₁ = Leachate runoff coefficient for the operational unit, generally taken as 0.5–0.8

A₂ = Area of the intermediate cover unit watershed (m²)

C₂ = Leachate runoff coefficient for the intermediate cover unit, generally taken as 0.4–0.6

A₃ = Area of the final cover unit watershed (m²)

C₃ = Leachate runoff coefficient for the final cover unit, generally taken as 0.1–0.2

Recommended Reading: Scheme for Garbage Leachate Treatment Process