2025 Volume 37 Issue 2 Pages 11-32
Leachate recirculation is a process in which leachate is returned to the disposal surface, generally to enhance the biological degradation of the disposed waste by applying moisture and reducing the leachate concentration to an acceptable level before discharge. On the other hand, the authors apply leachate recirculation to minimize leachate discharge in semi-arid areas, where evapotranspiration is relatively high in the research area. This paper aims to describe the water balance mechanism by examining the climatic conditions and the waste received at the Baruni landfill. The analysis addresses an improvement measure for a semi-aerobic disposal system that was rehabilitated in 2016 and is not complying with operational guidelines and includes a small open pond causing leachate overflow. Factors such as external surface water inflow and runoff, recirculation, underground water intrusion, and evapotranspiration were considered. Meteorological data and information, along with solid waste data from the study area, were collected and analyzed to establish the pond's holding capacity and potential recirculation volume, after outlining the landfill's water balance. The developed model included a simulation of a series of landfill cells and ponds. It describes how leachate is generated and reduced by incorporating external inflows and outflows. In the case study, the model was simplified to a single cell and a single pond model for quantification purposes. This paper further introduces a methodology to identify alternative measures through the design of proper capacities in pond size and pump capacity for recirculation purposes. The authors referred to this as the “vector and contour method”. It aims to enhance evapotranspiration to decrease the overflow amount and duration. This method is a critical metric for understanding the dynamics of leachate management. It outlines the extent of leachate overflow and specifies the conditions under which effective prevention and reduction can be achieved. Specific focus was placed on the relationship between leachate recirculation practices and the determination of pond size for optimal leachate management. Among the proposed alternative solutions regarding pond size and pump capacity to store leachate volumes in the leachate pond, the economical aspect was also considered for operating a leachate recirculation pump. This approach offers landfill operators a practical tool for predicting and managing leachate volumes across varying climatic conditions.
