Which of the following best describes the function of a drain field?

The function of a drain field is to treat and disperse effluent from the septic tank, making this the most accurate description. Once wastewater leaves the septic tank, it contains both liquid effluent and solid waste. The drain field, also known as a leach field, is designed to handle the liquids by allowing them to seep into the surrounding soil. Here, beneficial bacteria in the soil break down contaminants, effectively treating the effluent before it reenters the groundwater system.

This process is critical for ensuring that harmful substances do not enter the water table, thus protecting both public health and the environment. The drain field's layout, including the perforated pipes and surrounding soil, plays a vital role in promoting this natural filtration process. Overall, the drain field is an essential part of a septic system that enhances the treatment of wastewater, so its primary function is indeed to treat and disperse effluent from the septic tank.