Municipal waste management has become a huge challenge, especially in urban areas due to rapid population growth, industrialization, and changing consumption patterns. Conventional waste disposal methods, such as landfilling and incineration are not sustainable anymore. These methods significantly contribute to environmental degradation and biodiversity loss. Microorganisms could offer sustainable and eco-friendly solutions to current waste management issues. Due to their huge metabolic diversity, microorganisms are capable of degrading various waste materials, detoxify hazardous compounds, and recover valuable resources from waste. This chapter explores microbial processes involved in waste degradation, including aerobic and anaerobic digestion, bioremediation, and wastewater treatment. Furthermore, the chapter also discusses about the applications of microbiome engineering, omics technologies, and CRISPR-associated gene-editing tools in waste treatment processes. Challenges that prevent large-scale implementation of microbial-driven waste treatment technologies are also discussed in this chapter.