What slope must be maintained for the bottom of the pit in an intermittent sand filter system?

The correct slope for the bottom of the pit in an intermittent sand filter system is 1 inch of fall per 1 foot of run. This specific slope is crucial for ensuring proper drainage and distribution of effluent throughout the sand filter media. A 1:1 slope maintains a balance that allows for optimal percolation of water through the sand, preventing pooling and ensuring that the filtration process functions effectively.

Proper slope helps facilitate gravity flow, which is essential in these systems. If the slope is too steep, it may lead to rapid runoff, causing inadequate filtration and potential bypass of contaminants. Conversely, if the slope is too shallow, it could result in stagnant water, leading to clogs or inefficient treatment of wastewater.

In contrast, other proposed slopes could cause either an overly rapid movement of effluent through the filter material, reducing treatment effectiveness, or hinder proper drainage, leading to system failure. The specified 1 inch per foot ensures a conducive environment for the aerobic bacterial processes that occur in the sand filter, enhancing the overall performance of the septic system.