ABSTRACT
The removal of a considerable amount of biological oxygen demand, chemical oxygen demand, and suspended solids are one of the important outcomes of the secondary treatment of wastewater. In addition, biological treatment is responsible for removing trace levels of phosphorus, heavy metals, and nitrogen. Tertiary treatment is performed after secondary treatment to further improve the treated effluent’s quality. The term “advanced wastewater treatment” refers to a further treatment process that is carried out to reduce the amounts of organic substances, turbidity, nitrogen, phosphorus, metals, and pathogens present in wastewater after it has been subjected to secondary treatment. If nitrogen and phosphorus are found in the effluent produced by secondary treatment operations, the discharge of that effluent has the potential to cause eutrophication in the body of water that it is introduced to. Before the treated effluent may be considered for reuse, the dissolved, suspended, and colloidal particles need to be removed. Therefore, tertiary treatment is required in order to meet the norms for discharge and reuse. In this context, the different tertiary treatments, such as chemical precipitation, filtration, adsorption, and disinfection, have been discussed in this chapter.
