Methods and apparatuses for determining the volume of a substance in a flexible tank

A method of determining a volume of a substance contained in a collapsible tank placed on a surface, the method comprising:

• receiving a first set of sensor data from a first plurality of load-sensitive sensors disposed on at least a first region of the surface and a second set of sensor data from a second plurality of load-sensitive sensors disposed on a second region of the surface, wherein the first region of the surface is covered by the collapsible tank when the collapsible tank is empty, and is exposed when the collapsible tank is full, and wherein the second region of the surface is covered by the collapsible tank when the collapsible tank is full;
• determining a pressure level profile of the collapsible tank using at least the second set of sensor data from the second set of load-sensitive sensors;
• calculating a weight of the substance using the pressure level profile;
• and
• calculating a volume of the substance using the weight and density of the substance.