Drowning in a dream signifies that life (water) is threatening or overwhelming (coming in on top of you).
To save someone from drowning indicates that you do spirit rescue. Spirit rescue can be done consciously or when you have left your body during sleep.
Drugs indicate you suppress your feelings.
To be drunk indicates you suppress your feelings.
A duct for a ventilation system symbolizes your respiratory system and lungs.
A dustbin, a receptacle for waste, symbolizes your elimination system and colon.
A dustpan indicates your elimination system, the need to eliminate something from your diet, or the need to eliminate conditioning. For example, to dream of a silver dustpan tells you that keeping your system clean is directly linked to your ability to intuit things. It also means that you can use your intuition to help you overcome issues.