Effective wastewater treatment is essential to ensure environmental and public health. Recent decades have seen the development of processes that harness the power of biological systems to remove excess chemicals, nutrients, pollutants, and pathogens from wastewater originating from industrial, agricultural, and urban sources. Bioremediation and biotreatment techniques employ bacteria, algae, fungi, plants, and even animals, to naturally absorb, accumulate, and degrade target contaminants. Biological wastewater remediation and treatment are often more cost-effective, scalable, easier to maintain, and, ultimately, sustainable than conventional physicochemical methods.