https://www.healthywa.wa.gov.au/Articles/U_Z/Understanding-Septic-Tank-Systems
Most unsewered developments in Western Australia use septic tank systems to treat and dispose of sewage, also referred to as wastewater. Septic tank systems generally consist of one or two watertight cylindrical tanks called septic tanks and one or two sets of drainage receptacles which have holes in their sides and no base e.g. leach drains or soakwells.
https://www.healthywa.wa.gov.au/Articles/A_E/Expressing-and-storing-breast-milk
There may be times where you need to express your milk such as when you return to work, your baby was born prematurely or is unwell, is unable to suck well, is away from you, or if your breasts are too full. This page includes information about expressing, storing, cleaning equipment, transporting and preparing expressed breastmilk for your baby.