Gas-Liquid-Solid (GLS) Separator
In order to achieve highest possible sludge hold up under operational conditions, it is necessary to equip the UASB reactor with a GLS separator device. The main objective of this design is to facilitate the sludge return without help of any external energy and control device. The guidelines for shapes and design of GLS separator are given by Lettinga and Hulshoff. The GLS should be designed to meet the requirements such as, provision of enough gas-water interface inside the gas dome, sufficient settling area out side the dome to control surface overflow rate; and sufficient aperture opening at bottom to avoid turbulence due to high inlet velocity of liquid in the settler, to allow proper return of solid back to the reactor. Due attention has to be paid to the geometry of the unit and its hydraulics, to ensure proper working of the GLS separator.