Disposal not Vented

[Bruce Ramsey]

The kitchen sink and disposal share the waste pipe but only the sink is vented. Shouldn't the disposal connect before the vent?

[Scott Patterson]

That is a creative, but it is wrong in so many ways.

The best way, IMO would be to connect it like this; The disposal should connect into the tailpiece of the sink and then a single trap and then it connects to the drain line and then the AAV is connected to the top of the line and it extends up to the flood rim of the sink.

Keep in mind that the AAV is actually the vent for the fixtures on this line. If anything is added to the line after the AAV it will not be vented.