A sewage ejector pump and a grinder pump are both types of sewer pumps, but they work in slightly different ways. A sewage ejector pump moves solid waste and wastewater from toilets and drains to the main sewer line. A grinder pump is designed for homes or businesses where the sewer is located too far away from the building for gravity to do the work. It grinds up solid waste and pumps it through pipes to the main sewer line.