Why does the Hach CBOD procedure use a different amount of nitrification inhibitor than Standard Methods?

Document ID

Document ID TE171

Version

Version 4.0

Status

Status Published

Published Date

Published Date 08/28/2018
Question
Why does the Hach CBOD procedure use a different amount of nitrification inhibitor than Standard Methods?
Summary
Amount of Nitrification Inhibitor for CBOD
Answer
Previous versions of Standard Methods have referenced varying amounts of 2-chloro-6-(trichloromethyl) pyridine (TCMP) for testing Carbonaceous Biochemical Oxygen Demand (CBOD), but the actual amount in the sample is the same: 3 mg. 

Nitrification Inhibitor for BOD, Formula 2533™, TCMP, 35 g (Product # 253335) is referenced in Hach method 8043. This nitrification inhibitor contains 2% TCMP. Adding 0.160 g of this into the sample introduces 3 mg (0.160 *0.02) of TCMP, which is the same amount used in Standard Methods 5210.
Attachments

Was this answer helpful?

Submitting...
Thank you for your feedback!
There was an error with your submission. Please try again.