just had this made by a local millwright/fab shop , for some tees
Basically a 3 chamber box with drain at one end with tray on top to catch crud.
We used tees in the tray for the first week and it caught a ton of sludge , now trying a 1/2" inch filter fabric with a layer of felt under.
Bio diesel guys use a felt with different micron ratings I am going to order some an give it a try.
This one is approx 30" x 21" and when I calculated the numbers it holds about 107litres 29 gallons
Seems to work very well and just a faint pink coloured water comes out at the end.