InSinkErator Bio-Charge Cartridge Replacement fits Septic Disposer and lasts 3 to 4 months with average use. Bio-Charge cartridge equals 4 bottles of other septic treatments. And Bio-Charge contains a citrus scent to help control odors from the sink and drain. There's also a surfactant to help break down soap and grease film that accumulates in drainpipes.