Where must the outlet pipe in a grease interceptor originate?

The outlet pipe in a grease interceptor is typically required to be positioned a specific distance from the tank bottom in order to effectively separate the grease and solid waste. The correct placement, which is 8 inches from the tank bottom, ensures that the interceptor can perform efficiently by allowing heavier solids to remain settled at the bottom of the tank while enabling the lighter grease to flow out through the outlet. This configuration helps maintain proper functioning by minimizing the chances of solids exiting the tank along with the grease, thus preventing clogs in later sewer lines and protecting wastewater treatment systems.

The specified distance ensures that the separation process is optimized and helps in better management of the waste components contained within the interceptor. Other options suggest different distances, which may not support the effective operation and could disrupt the intended design for waste management.