Because FOG is based on a solvent extraction and evaporation of the solvent and weighing the residue, most instrumental methods use some sort of spectroscopy (IR, UV, etc to measure the concentration of "oil" in the water. Some units even perform a solvent extraction of the "oil for analysis.

This type of analysis compares favorably with conventional FOG analysis if the composition of the '"oil" is relatively constant and only the concentration changes. However, the results may show considerable variance from the FOG analysis if both the composition and concentration of the oil in the sample vary. If you are familiar with the wastewater contaminants, you may decide that an on-line analyzer is appropriate. Just one more caution, some contaminants that are not oil may also be extracted in the conventional FOG analysis.

grrun    

Thanks grrun!!

The composition of the oil stream is consistent, only the concentration changes.

Any idea of some companies that offer a hassle-free unit?