Chat with whoever is your go to septic crew. There’s pretty likely a period of time where you’re safe to use your system without power.

In that case all you need is to fill a few buckets (or your tub) with water before a possible power outage. Then you go poop and dump a bunch of water into the toilet and it will flush just like normal.

I absolutely blew my wife’s mind with this tidbit the first time we lost power at our house. Luckily we have a pond so unlimited flush water lol