Sewage system

Can someone tell me more about a aerated diy sewage treatment system please . Looking at IBC tanks and  how too,s and pumping sewage up a slight grade .
Need to know about sizing and how to determine the best tank size Vs people in house . Whats the time for treatment of sewage in the system ie if tanks too small it will not take the surge volume function Vs tanks too large its a pain too install and service . Looking for help here please.
Anyone done this before .

Many thanks

Have you looked into flush toilet worm systems, if you might want a system with fewer moving parts?  

http://www.solviva.com/wastewater.htm

http://www.vermicompostingtoilets.net/

https://www.permaculture.co.uk/readers-solutions/how-make-vermicomposting-flush-toilet

Thanks for reply
Thats very interesting . I must admit the pictures and descriptions of septic systems effect is not very  encouraging.
Yes the fewer mechanical parts the better , i will look into this more , all options being considered here.