Final answer:
Biotechnology in wastewater treatment leverages microorganisms to eliminate organic matter, nutrients, and contaminants through processes like aerobic bacterial decomposition and bioremediation, which can include advanced tertiary treatments like sand and carbon filtration.
Step-by-step explanation:
Biotechnology in wastewater treatment utilizes microorganisms for various purposes, including the removal of organic matter, degradation of nutrients, purification of water, and treatment of contaminants. These microorganisms, often selected or genetically engineered, carry out processes such as aerobic bacterial decomposition and enhanced biological phosphorus removal. They are instrumental in tertiary treatment steps and in bioremediation technologies, which are used for the cleanup of both soil and water, and can degrade xenobiotics and other environmental contaminants.
During secondary treatment, aerobic bacteria are cultivated in either fixed film or suspended growth systems, where they break down organic pollutants. In tertiary treatment, further filtration may be employed, like sand filtration and carbon filtration. These processes contribute to the four key purposes of wastewater treatment: to remove solid and organic matter, reduce pollution, kill harmful bacteria, and sometimes, make the water clean enough for reuse in non-drinking applications.