A Global Overview of Traditional Biological Treatment Technologies

Trace organic contaminants like pharmaceuticals, pesticides, surfactants, and phenolic compounds impose a threat to human health as well as aquatic plants and animals. A significant source of these contaminants entering the aquatic ecosystem is through the discharge of sewage from households, veterinary, agricultural runoff, pharmaceutical industries, and others. Besides, biological treatments are cost-effective and environmentally friendly technologies for wastewater treatment. Thus, it is essential to discuss and compare the traditional biological technologies that effectively treat trace organics from sewage. Different microbes present in the biological setups might break these organics into more environmentally liable and non-toxic compounds. However, further development of efficacious biological technologies is crucial for future full-scale application and commercialization. Therefore, this chapter deals with the technologies, such as activated sludge process, trickling filter, up-flow anaerobic sludge blanket reactor, stabilization ponds, and others used to remove organics present in the wastewater. The factors impacting the removal efficiency, like organic loading rate, and hydraulic retention time have also been elucidated. In addition, the mechanism of removal of organics in traditional biological technologies is comprehensively discussed. Lastly, the need for hybrid treatment technologies for remediation of organic pollutants has been discussed.