Clogged drains are a common home kitchen problem. Grease and food debris stick together as the water cools father down the drain, forming clumps that often need chemical or mechanical dissolution. Simply preventing these grease clogs from occurring can be much cheaper than repairing the damage after the fact. By converting a 55-galllon plastic water barrel, you can easily build a grease trap for a house.
Draw a straight line all the way around the drum six inches from the top. Cut the top off of the barrel with the hand saw, carefully following the drawn line. Set the removed top aside. This portion will serve as the removable lid, allowing easy access for cleaning.
Measure the outside diameter of your sink's outtake pipe at the point where you are going to install the trap. Draw circles as wide as the pipe on two opposite sides (east and west) of the barrel, 6 inches from the open rim of the drum. Then cut around the outside of the outlines with the razor pen - the holes left in the barrel should be just slightly larger than the pipe.
Measure both the height and width of the inside of the barrel. Cut the plastic sheet to the barrel's inside width, and a height six inches shorter than the barrel. Position the sheet in the barrel so that it hangs straight down the middle of the space between the intake and outtake holes and the top edge is flush with the rim of the barrel. Seal its side edges to the inner sides of the barrel with plumbing sealant.
Set the barrel in its install point, as close to the sink as possible. Reroute the pipe from the sink to the intake (west) side and from the soil line to the outtake (east) side and insert the pipes into the holes in the trap. Use plumbing sealant to seal any open space between the holes and the pipes.
Attach an elbow joint to the end of outtake pipe inside the trap, with the opening of the joint facing the bottom of the barrel. Add a 6-inch length of pipe to open end of the joint. Place the top onto the barrel and close.