... is over 15ppm,oil in water monitor would transmit alarm signal,change valve(N.O,N.C solenoid valve)operating,first ... over 15ppm,oil in water monitor would transmit alarm signal again.Solenoid valve returning to tank shoulb be opened ,treatment water return ... collection on the top of first separator,Oil level detector to transmit signal,pneumatic type separator device let first stage treatment solenoid ...