Mars Transit Vehicle Trash Ejector

On the way to and from Mars, the astronauts are going to be eating food, replacing broken hardware and using the toilet. As you might imagine, there are many reasons why they would like to get rid of their trash instead of keeping it with them as they travel. How is it possible to throw away the trash without losing air in the space craft? Design and build a trash ejector that doesn't release any of the air needed for the space craft.