Bullet Septic Tank
It’s called the Bullet because it is so shallow, and only takes approximately 1 hour to install.
The bullet septic tank has a heavy duty rib design means you can install it with no concrete. Just use some gravel to backfill around it.
You can also attach a riser to it, which allows you to sink the Bullet deeper into the ground. The 1 metre riser comes free with the tank.