SEWAGE DEPARTMENT TRAINING PROGRAM
How to Build a Free Access Gravity Sandfilter
Next, install the delivery pipe. The delivery pipe is constructed from PVC pipe at least 3 inches in diameter. The pipe is perforated by a line of 1/2 inch holes with a solid section where it enters the tank. The end of the pipe is capped and the holes are turned slightly to the side. This allows the effluent to fill the pipe and dribble out all of the holes.
End view of the delivery pipe. By rotating the holes to a 45% angle from the bottom, the effluent will fill the pipe before dripping out.
