The wedge wire screen on the top of the hopper facilitates in the separation of the liquid versus solids.
Liquids flow through the screen and drop into the collection hopper in the bottom, to be pumped out into large storage container later.
This has the benefits of minimizing cost of sending this to waste water for treatment and increasing profit by selling the marination.
The larger food solids or premium offal product can then be collected and used in pet food operations. Again being sold for profit instead of having to be disposed of by other means.