Patent ID: 8252188

Claim:
In a separator tank for separating F.O.G. from an effluent that contains F.O.G. in which the tank has a size to enable stratification of a layer of F.O.G. present in the tank on water in the tank, the method comprising in sequence: taking a first measure of the temperature of two thermocouples in the tank, applying heat to the two thermocouples in the tank for a fixed period of time, taking a second measure of the temperature of two thermocouples in the tank, evaluating differences in the first and second measures of the temperature for the two thermocouples, and for each thermocouple, if the difference in the first and second measures of the temperature for that thermocouple is below a threshold, generating a signal indicative that the thermocouple is immersed in water in the tank; and if the difference in the first and second measures of the temperature for that thermocouple exceeds the threshold, generating a signal indicative that the thermocouple is immersed in F.O.G.