Which principle does the leach field operate on?

The leach field, also known as a drain field, operates primarily on the principles of gravity and soil absorption. When wastewater is released from a septic tank into the leach field, it flow by gravity through a network of perforated pipes. The soil in the leach field plays a crucial role in treating the wastewater through natural processes.

The gravity-driven flow allows the effluent to distribute evenly throughout the leach field, and the soil surrounding the pipes absorbs the water. This soil acts as a filter, removing contaminants through processes such as adsorption and biological treatment. Microorganisms present in the soil also break down harmful pathogens and nutrients, further purifying the water before it eventually percolates down into the groundwater.

While other options mention processes that play roles in wastewater treatment, they do not specifically describe how leach fields function. For instance, while mechanical filtration and oxidation may occur in certain specialized treatment systems, they are not the primary mechanisms of action in a traditional leach field. Similarly, running water and chemical treatments suggest a more complex system where chemicals are used to manage wastewater, which differs from the natural and straightforward method employed in leach fields. Lastly, evaporation and condensation pertain more to the water cycle and do not relate to the