Which of the following is a common source of nitrogen in wastewater?

Human waste is a common source of nitrogen in wastewater because it contains significant amounts of nitrogenous compounds such as urea and ammonia. These compounds originate from the breakdown of proteins in the human body. When human waste is introduced into wastewater systems, it contributes to the overall nitrogen load that must be managed and treated to prevent environmental issues, such as eutrophication in water bodies.

The presence of nitrogen in wastewater is of particular concern, as high nitrogen levels can lead to excessive growth of algae in aquatic environments, ultimately harming water quality and aquatic life. Hence, treatment processes in wastewater management systems must address this nitrogen content effectively. In contrast, industrial chemicals, plastic waste, and metal scraps do not typically contain nitrogen in significant amounts, making them less relevant as direct sources of nitrogen in wastewater.