Glad yours went ok.
I got to have a vent now on my septic woes - sorry - but it maybe useful to someone taking up a similar operation.
As you may know we have a campsite here and have been upgrading our toilet facilities for an estimate 60 person per night campsite, its seasonal but we told the planners that the toilets would be in use all year (or we would need a three stage waste system - we also would leave the toilets open all year anyway, but not like the system is going to have a hammering all year).
I had to buy a tank that basically outputs clean water - 6m long - 3.5 high and 2.6 wide - and needs constant power to run - it needs 500m of soakaway pipes 8"
Its quite literally almost more work than building the toilets.
I'd be surprised if only the first 100 meters of soakaway was ever used by the system.
I've also had letters asking about my personal 'hole in da ground' asking to register and get advice. - er no, it works fine as it is thanks.