What do you do with things which should not go into the septic tank?
There is no difference between being on a septic tank and being on a sewerage system when it comes to Household Sewer Pollution. You handle it just the same as someone who lives in a house on a sewerage system.
The Kitchen Sink Do's, Toilet and Shower Do's and Gully Trap/Stormwater Do's pages apply to you and your septic tank just as much as to people on a sewerage system.