Various embodiments of the present invention are directed to waste disposal methods and systems. In one embodiment of the present invention, a waste disposal system is positioned under a sink in a building connected to a septic system for disposal of food waste and wastewater. The waste disposal system includes a grinding chamber, a centrifugal-pump chamber, and a straining chamber for separating food waste from wastewater. The straining chamber includes a filtration basket, and an outlet pipe.