The primary purpose of a sand filter in wastewater treatment is to?

The primary purpose of a sand filter in wastewater treatment is to remove bacteria and suspended solids. Sand filters function by utilizing the physical properties of sand to trap particles and microorganisms present in the wastewater. As the wastewater flows through the layers of sand, suspended solids are captured, effectively filtering out larger particles. Additionally, the surface of the sand grains provides a habitat for biofilm formation, where bacteria can attach and grow. These bacteria help to break down organic matter and further reduce pathogens, thereby improving the overall quality of the treated water before it is discharged or used for irrigation.

In this context, while other options mention processes that may occur in wastewater treatment systems, they do not capture the primary function specifically associated with sand filters. Heavy metal removal is typically accomplished through different types of filtration and chemical treatments. Increasing pH levels is generally not a primary function of sand filters, as they focus more on physical filtration. Enhancing nutrient removal often involves additional processes such as biological treatment or chemical methods, rather than the physical mechanism of a sand filter.