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(T/EH010) A new method for measuring nitrification inhibition of chemical compounds in the pharmaceutical industry. Lo Biundo, Giuseppe1, Newell, Katy 1, New, Anthony1, Freitas dos Santos, Luisa 1, 1 ABSTRACT- The presence of ammonia in waste waters is causing growing concern due to the toxicity of free ammonia to fish and many other aquatic species in receiving waters. Nitrification is a key step in the nitrogen removal process and current methods to assess nitrification inhibition are relatively time consuming and lack sensitivity. The Environmental Research Laboratory at SmithKline Beecham (SB) Pharmaceuticals, has started an experimental program looking at new methods for measuring nitrification inhibition of chemicals, waste waters, and new drug compounds. One of the method being investigated uses a titrimetric biosensor called ANITA (Activity and NITrification Analyser) (Massone et al., (1998) Wat. Env. Res. 70 (3) 343-350). The method, simple and fast, allows to generate results in approximately two hours. A number of chemicals relevant to pharmaceutical processes (e.g. chlorolophenols, biguanides and amines), waste streams, and drug substances are being investigated. The results obtained from six different tests carried out on 3,5 DCP using a pure nitrifying microbial culture generated an EC50 in the range of 0.4 - 1.3 mg/L. These EC50 values are within the range previously reported by other authors (0.5 - 3.6 mg/L) who used different methods [Hayes E. et al. (1998), Wat. Sci. Tech. 37(12) 193-196 and StrotmanU. J. et al. (1995), Ecotox. & Envir. safety 30(3) 269-273]. Also results obtained on other compounds will be presented and discussed. Finally, classical measurements of ammonia, nitrate and nitrate using photometric methods and Ion Chromatography were performed in parallel and results will be compared and discussed. The work performed so far has demonstrated that the methodology and the system used are reliable, fast, and no extra analytical work is required. This makes the method and the system economical when compared with alternative systems or methods. Key words: Nitrification inhibition, titrimetric method, ANITA biosensor |
