Which treatment method is characterized by low maintenance and operational costs?

Slow sand filters are characterized by low maintenance and operational costs primarily due to their simple design and effectiveness in removing contaminants without the need for extensive mechanical processes or frequent chemical dosing.

These filters operate on the principle of natural biological filtration, where a layer of biological material, known as a schmutzdecke, forms on the surface of the sand as microorganisms proliferate. This layer helps in effectively trapping particles and microorganisms, while also contributing to the degradation of organic matter.

The simplicity of slow sand filters means that they require less energy and fewer materials than more complex systems, such as rapid sand filters or ultrafiltration. Additionally, they have lower operational oversight requirements, allowing facilities to benefit from reduced labor costs. Maintenance typically involves periodic cleaning of the filter and replacing sand, which can be done less frequently compared to other treatment methods that require constant monitoring and intervention to maintain optimal performance.

This combination of low operational and maintenance needs makes slow sand filters an attractive option for drinking water treatment, particularly in small or rural water systems where resources may be limited.