The 24th Edition of Standard Methods (SM) for the Examination of Water and Wastewater has been published and is now available.

One of the 81 new methods in the 24th Edition of Standard Methods is 4500-N E which measures Total Nitrogen and Total Kjeldahl Nitrogen (TKN) using a TOC-L. We expect 4500-N E to be included in 40 CFR Part 136 for the analysis of nitrogen in wastewaters.

The 24th edition of the SM also includes revisions to Method 5310 Part A. Here, Standard Methods better describes requirements at 40 CFR part 133.104(b) that allow TOC to be used in the place of BOD for compliance monitoring. Besides SM 4500-N E and analysis of BOD, the TOC-L can be used for SM 5310B, EPA 415.1, EPA 9060A, ISO 8245, ISO 20236, ASTM D7573, ASTM D8083, USP<643>, and more.