Plumbing Guidance Needed

[MRW]

I am rebuilding a mountain cabin and it will have;
1. composting toilets
2. grey water system for everything but the kitchen sink

Questions:
1. Should I install a residential grease trap for the kitchen sink?
2. I have a new metal roof with no penetrations and because I am not using a sewer system or septic system (composting toilets) would it reasonable to install a AAV under the kitchen and bathroom sinks vs. venting through the roof which I don't want to do.

Any advice/comments would be appreciated. Thank you.

 

[Terry]

The AAV doesn't work unless you have some through the roof venting. The AAV is an add on.

Also, the roof will need ventilation to vent moisture out too. That's a separate issue.

 

[Sponsor]

 

[MRW]

Thx. Terry for response. AAV won't work because of positive pressure or ?