• It is achieved by creating suitable microorganisms and environmental conditions in biological wastewater generated as a result of domestic or industrial use.
• The wastewater generated by the rapid increase in population and industrialization has exceeded the amount that nature can absorb and has exposed the receiving environments to the danger of pollution. In order to prevent this situation, which may negatively affect the natural ecological balance and prevent other beneficial uses, the necessity of treating wastewater before disposal has come to the fore.
• The most effective method for removing organic pollutants is "biological treatment". It can be said that it is. Biological treatment is the process of breaking down suspended or dissolved organic substances in wastewater with the help of bacteria and transforming them into fixed inorganic compounds that remain in liquid or escape to the atmosphere in gaseous form with collapsible biological flocs.
• Biological treatment systems can be classified in different ways. These systems, which are classified as airy (aerobic) and airless (anaerobic) according to the presence of oxygen in the environment, can also be called suspended and fixed film (biofilm) processes, depending on the state of the microorganisms used in the system.