Landfills represent complex ecosystems where numerous chemical processes significantly impact environmental dynamics and human health. Understanding the chemistry of landfills is crucial for analyzing the composition of waste, which includes inorganic and organic substances. Each substance undergoes specific chemical processes, resulting in the creation of leachate full of pollutants and gases such as carbon dioxide and methane. Interactions between microbial activities during biodegradation at landfills are essential for the decomposition of complex organic compounds. Pollutants, including organic chemicals, microorganisms, and heavy metals, are present in these aqueous solutions, which can pose a serious threat to ecosystems and human health. Therefore, effective gas collection and management systems are necessary to reduce the negative impacts of landfills on the environment. Innovative remediation strategies, such as enhanced oxidation processes and biodegradation, are vital for the purification of contaminated groundwater and soil, promoting environmentally friendly waste management. Future research is directed toward a deeper understanding of the complex chemistry of landfills and the development of environmentally sustainable waste management approaches, which will contribute to a healthier planet. Special attention is given to the development of new technologies for detecting and neutralizing pollutants and the implementation of better regulations and waste management policies. This paper investigates the chemical processes in landfills, analyzes the impact of microbial activity on waste decomposition, and considers innovative remediation and gas management methods to mitigate negative effects on the environment and human health. The conclusions of this research emphasize the importance of an interdisciplinary approach to addressing landfill-related issues, including the collaboration of scientists, engineers, and policymakers in creating sustainable solutions.