Leachate recirculation in a landfill: a simple 1-D model

Leachate is the liquid phase present in the pore spaces of the solid waste material in a landfill. The leachate arises from the liquid content of the waste when it is placed in the landfill, and from rainfall infiltration of water through the upper surface of the landfill. Leachate may be collected from the waste using wells or drains. It can then either be treated and disposed of, or reintroduced into the waste material through an artificial recharge system. This latter process is known as leachate recirculation; managing the leachate in this way may be used to optimise both gas generation and leachate treatment systems.In this paper, a simple numerical model of the concept of landfill leachate recirculation is developed and used to gain some insight into the basic mechanics of the process by identifying the underlying relationships between the key parameters involved. The analytical approach used in the model is then validated with reference to real data from the landfill at Beddington, Croydon (UK)