What is the expected treatment performance level of a properly installed intermittent sand filter system?

A properly installed intermittent sand filter system is designed to achieve a Treatment Level B performance. This classification indicates that the system is capable of effectively treating wastewater to a degree that removes significant amounts of biochemical oxygen demand (BOD), suspended solids, and pathogens, which are critical parameters in wastewater treatment.

Intermittent sand filters operate by allowing wastewater to flow through a bed of sand, which acts as a natural filter. The design and operation of these systems facilitate aerobic conditions that promote the growth of beneficial microorganisms. These microorganisms break down organic matter in the wastewater, thus enhancing the treatment process.

Treatment Level B specifically refers to the system's ability to reduce pollutants to levels that are suitable for further treatment or disposal. As such, systems achieving this level of performance are often suitable for use in groundwater recharge or discharge to surface water with less risk of environmental impact.

In contrast, levels A, C, and D indicate varying degrees of treatment effectiveness. Level A would exceed Treatment Level B, possibly incorporating advanced treatment technologies, while Level C and D would reflect reduced treatment performance and likely higher levels of remaining contaminants in the effluent. Overall, the classification of intermittent sand filters as achieving Treatment Level B reinforces their role as effective, natural wastewater treatment solutions.