Fig. 4. Diagrammatic representation of the dual-drain circular culture tanks in a typical recirculating filtration system used at the USDA ARS National Cold Water Marine
Aquaculture Center in Franklin, Maine; water exiting the bottom-center drain of the culture tank (1) is first treated across a radial flow settler (2) before the flow is piped,
along with the flow exiting the tank sidewall drain, to the micro-screen drum filter (3).