Water loss in an UASB reactor ?

Hola a todos ! I have this doubt about how to calculate the water loss ( perte de charge in French or pérdida de carga in Spanish) in a UASB reactor (Upflow anaerobic sludge blanket). It has 5,30 m of hight HTR = 14,08 h velocity of flow = 0,40 m/h If anybody needs more information, do not hesitate in contact me. Thank you in advance ! Have a good day !