This European standard specifies detennination of the biochemical oxygen demand of waters of undiiuted samples. This standard is applicable to aii waters having biochemical oxygen demands greater than or equal to the limit of determination 0,5 mgíl of oxygen and not exceedmg 6 mg4 of oxygen. In this standard, the lunit of determination, DL. where SB is the within series standard deviaîion, k,g5m is the student t-value, with f is the degrees of freedom for the determination of SB and n is the number of analysis for detemination of the blank in an analytical series. SB is calculated from determinations of real samples with a BOD contentraton near the estimated DL.The resuits obtained are the product of a combination of biochemical and chemical reactions. They do not have the rigorous and unambiguous character of those resulímg from, for example, a singie, well-defined, chemid process. Nevertheless, they provide an indication from which the quality of waters can be estimated. The test can be influenced by the presence of various substances. Those which are toxic to microorganisms, for example bactericides, toxic metals or free chlorine, will inhibit biochemical oxidation. The presence of algae or nitrifymg microorganisms can produce high results. In these situations a modification of the method (see annex B or as described in EN 18941). It is absolutely esentiaì that tests conducted according to this standard are carried out by suitably quaiified staff. Annex A describes alternative incubation periods. Annex B describes procedures for modification of the method by addition of seeding makriaì, saìts, inhibition of nihification by dylthiourea (ATU) addition, neutsalization, homogenization and/or fjiWon. These modifications may be found necessary for specific evaluations of the water qual@ of receiving waters.
EN 1899-2-1998由欧洲标准化委员会 IX-CEN 发布于 1998-03-01。
EN 1899-2-1998 在中国标准分类中归属于: C51 环境卫生。
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