A monitoring camera has a base, a camera module and a casing. The bleed-off mechanism is in fluid communication with a flow path extending from a wellhead valve or wellbore and designed for connection with a vacuum truck. In addition, the emitted light intensity of the EL device may be easily controlled by simply varying the voltage or the frequency of the applied current. A control assembly is coupled with at least the tank and drain valve assembly, and is operable to actuate the drain valve assembly after a predetermined number of movements of the tank between the elevated and lowered positions thereof.