BIBLIOMETRIC ANALYSIS ON RESEARCH TRENDS IN LANDFILL LEACHATE TREATMENT TECHNOLOGIES

Abstract

Landfill leachate treatment remains as one of global environmental challenges due to the complex composition of leachate which contains high concentrations of organic matter, ammoniacal nitrogen, heavy metals and refractory pollutants that threaten water quality and ecological systems. Despite the growing number of studies addressing this issue, a comprehensive understanding of the research landscape is limited, making it necessary to systematically map trends, influential contributions and emerging themes. This study conducts a bibliometric analysis of leachate treatment technologies to identify scientific progress and intellectual structures shaping the field. Data were collected using the Scopus database through an advanced search with the keywords “landfill leachate” and “leachate treatment,” yielding 784 final records published between 2000 and 2025. The dataset was cleaned and harmonized using OpenRefine, statistical trends were analyzed with the Scopus analyzer, and knowledge structures were visualized using VOSviewer software. The results reveal a steady increase in publications with a notable surge after 2015, indicating growing global attention to leachate management. China leads research output, followed by Malaysia, Iran, and India, reflecting country priorities where landfilling remains the dominant waste disposal method.  Citation analysis highlights highly influential works focusing on electrochemical oxidation, advanced oxidation processes, adsorption, and biological technologies, while keyword co-occurrence mapping identifies emerging themes in electro-Fenton processes, membrane bioreactors, microbial community dynamics, and integrated treatment approaches. Collaboration patterns suggest increasing international partnerships, particularly among Asian and European countries. Hence, this study contributes to the body of knowledge by providing a holistic overview of research trends, influential publications and thematic clusters offering valuable insights for policymakers, landfill practitioners and researchers to advance sustainable solutions in landfill leachate treatment.