WEF Discussion Forums
Laboratory Management and Technical Issues
Allythiourea (ATU) for nitrification inihibitor
Has anyone experemented with the use of ATU for nitrification inhibitor? (Std. Methods 21st edition). We have been doing some side by side comparisons with the Hach (TCMP) and the ATU and have not been having any luck with the ATU affecting the sample at all.
I've tried it once and got nothing from it. I think it got ramrodded through the inclusion in SM because someone (Hach maybe) developed a CBOD seed that used it as its inhibitor. I guess the thought was, even if the seed doesn't contain nitrifiers, it would eliminate one step in preparing the batch. I've heard from several people that ATU just doesn't do as good a job as the pyridine based compound we are all familiar with.
We are also having problems with the effectiveness of ATU for CBOD. Interestingly, CBOD results are pretty reasonable for our treated effluent samples, based on parallels with TCMP. CBOD measured for primary effluent and GGA however, are often the same or greater than the respective BOD’s. When I checked the forum today I was I relieved to see it isn't just us. We hope to continue automated addition, thus the need for a soluble inhibitor, but unless we can find a way to get TCMP into solution, we’ll likely go back to adding powdered solid directly to bottles. I plan to continue to research this and I may also forward this concern to our DEQ regional representatives. I would appreciate hearing from others who have experienced problems, especially anyone who may have come up with a way around the TCMP solubility issue.