Which of the following does an ultrafiltration system remove from wastewater?

An ultrafiltration system is particularly effective at removing suspended solids from wastewater. This process utilizes a membrane that allows water to pass through while blocking larger particles, including suspended solids such as sediment, silt, and larger colloidal material.

By focusing on the size exclusion principle, ultrafiltration separates small dissolved substances and contaminants from the larger particles in the wastewater. This capability is crucial in wastewater treatment, as suspended solids can contribute to turbidity and negatively impact the quality of the effluent, as well as affect subsequent treatment processes.

While nutrients, pathogens, and gases are important elements in wastewater treatment, they are either not effectively removed by ultrafiltration or fall outside its primary function. Nutrients like nitrogen and phosphorus might require different treatment processes like biological treatment to reduce their concentrations. Pathogens may also require additional disinfection methods, such as chlorination or UV treatment, to ensure their complete removal. Gases are generally not a concern for ultrafiltration as they do not have a physical form that would be filtered out through membranes designed to separate based on size.

Thus, the primary role of ultrafiltration in wastewater treatment centers on the removal of suspended solids, making this the correct answer.