Hello everyone,

There is a formula that comes in the 23rd edition of the Standard Methods for the Examination of Water and Wastewater (section 9221 C, page 9-74) to calculate MPN in water analysis. In our lab, we need to know the origin of this formula because we can't get the same result of the example presented in the book. Also, we need to include this formula in a software.

PD: It's not the Thomas formula.

Thank you very much for your help.