To dream that you are at a dumpster, implies that you may feel that you are being dumped on. Alternatively, it indicates that you are trying to rid yourself of old, negative habits and bad characteristics.
To dream that you are secretly throwing something away in a dumpster, suggests that you are not taking responsibility for something.
A person or place that gets "dumped on" with unwanted things, responsibilities, tasks, or toxic emotions or mental "garbage." Secretly getting rid of things by putting them in a dumpster can mean you're shirking responsibilities, being dishonest, or trying to sneak around authority or rules somehow in your life.