Where the drainage system cannot drain by gravity to the sewer, an automatic pump or ejector can be used to discharge the soil and waste. The cover for the pump should be tightly sealed (gas-tight). Sumps, other than pneumatic ejectors, should be vented with a minimum 1-1/4-inch diameter vent pipe. Pumps use mechanical methods to discharge, and pneumatic ejectors use air pressure. Grinder pumps and ejectors pulverize solids to a near-liquid state and pump the slurry to the drainage system.