What does the term "nutrient recovery" refer to in sewage treatment?

The term "nutrient recovery" in sewage treatment specifically refers to the process of recovering and recycling essential nutrients, such as nitrogen and phosphorus, from wastewater. This practice is increasingly important in sustainable wastewater management as it not only helps to reduce environmental impact by minimizing nutrient pollution in water bodies but also enables the reuse of valuable nutrients that can be used in agriculture and other applications.

Recovering nutrients from sewage can help in mitigating issues such as eutrophication, where excess nutrients lead to algal blooms and other ecological disturbances in receiving waters. In addition to environmental benefits, nutrient recovery can contribute to a circular economy by turning waste into resources, thus promoting sustainable practices in the treatment of wastewater.

The other options describe different aspects of wastewater treatment but do not accurately capture the essence of nutrient recovery. For instance, filtering solids pertains to physical treatment processes, increasing sewage flow efficiency relates to hydraulic management, and chemical addition for pollutant neutralization concerns chemical treatment rather than the recovery of nutrients.