Systematic literature review of solar-powered landfill leachate sanitation: Challenges and research directions over the past decade

Researchers have documented the negative effects of refractory chemicals and emergent pollutants in landfill leachate (LL) that cannot be degraded using conventional methods. The propagation, invasion, and deleterious effects of several LL hazards affect aquatic species, the environment, and food outlets, causing significant safety issues. These include cancer risks, chronic exposure, and reproductive consequences. Alternatively, solar energy is a sustainable solution for treating landfill leachate to benefit humans and the environment. In this work, a thorough bibliometric and systematic analysis of studies that employed solar energy for landfill leachate remediation over the past decade was conducted in order to determine trends, and future research areas. In addition to the energy demand, the economic aspect and the advantages of using solar power to treat landfill leachate were discussed. Additionally, the study gives specific suggestions for future research purposes and important problems. The reviewed literature revealed that combining solar-based physical-chemical and biological processes has proven to be the most efficient method for landfill leachate degradation. It also appears from the bibliometric study that more collaboration and contribution are needed to develop solar-based landfill leachate treatment. This study concludes that solar-powered landfill leachate remediation techniques would considerably increase the effectiveness of treated leachate reutilization, advancing the cause of environmental sustainability.