The study looked at how clogging affects the drainage systems in landfills over time. They found that both chemical and biological clogging can build up in different parts of the system. The geotextile layer got clogged the most due to biological factors, while chemical clogging was more common in the gravel layers and pipes. Chemical clogging decreased at the bottom gravel layer over time. The balance between biological and chemical clogging changed as time passed. Understanding these patterns can help improve the design of drainage systems in landfills and develop better ways to prevent clogging.