五、請將下列英文譯成中文：（20 分） Meanwhile, the treated water is discharged from the bottom of the separator, through the oil content monitor and then either overboard or to the clean bilge tank, depending on residual oil content. Effluent will only be discharged overboard when its oil content is less than 15 ppm. Eventually the oil layer at the top of the separator increases sufficiently to trip a sensor which causes the separator drain solenoid to open. The accumulated oil is forced out through the oil discharge valve to the sludge tank.