Model bacteria, microbial populations, and soil habitats have all been shown to be adversely affected by carbon nanotubes (CNTs) in biological systems. Their presence may cause microbial populations and microbial diversity to be reduced in biological wastewater treatment procedures using activated sludge. In wastewater treatment systems, they do not completely disintegrate. They pose a significant risk to the health of microorganisms and the water quality in receiving water due to their shock loads and unexpected system-operating events during biological treatment. However, there is not enough data to say how they currently affect biological wastewater treatment systems. This chapter examined the state-of-the-art understanding of the dynamic effects of CNTs in wastewater treatment systems related to, but not limited to, their characteristics and severity of exposure to the treatment systems of its contaminants� degree of damage, mode of application and treatment effectiveness, and toxicants biodegradation. Additionally, the advantages and disadvantages of CNTs, their limitations and potential difficulties in their widespread application, as well as possible routes to achieving sustainable and secure CNT utilization in wastewater treatment, were explored along with the most recent research findings and perspectives. This chapter will aid in developing ideas for fresh methods to watch over and lessen the harmful effects of CNTs in future uses. © 2024 Elsevier Inc. All rights reserved.