Strongly loaded organic industrial waste water, i.e. from sugar- or paper-factories, need to be pre-treated before determining the BOD value. Because of the very high content of organic material in the sample, there is a disparity between the nutrients ratio (C:N:P). The lack of nitrogen (N) and phosphorus (P) causes a strong decrease in microbial capability and abundance, what lead to a subestimate of the BOD as a consequence.
In the following the pretreatment of a sample with so called dilutionwater is described, which contains the missing nutrients and microorganisms and with which an adequate BOD measurement will be obtained.

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The Biochemical Oxygen Demand over a testing period of n days (BODn) is precisely defined and associated with experimental standards. It represents the quantity of oxygen aspirated in the course of aerobic breakdown of organic substances by microorganisms.
BOD is thus an substantial feature in determining the effect of discharged effluents on the oxygen content of a water-course or on the oxygen demand of an effluent treatment plant. BOD levels are stated in mg/l of oxygen and are usually measured over a period of 5 days (BOD5).

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The Biochemical Oxygen Demand over a testing period of n days (BODn) is precisely defined and associated with experimental standards. It represents the quantity of oxygen aspirated in the course of aerobic breakdown of organic substances by microorganisms.
BOD is thus an substantial feature in determining the effect of discharged effluents on the oxygen content of a water-course or on the oxygen demand of an effluent treatment plant. BOD levels are stated in mg/l of oxygen and are usually measured over a period of 5 days (BOD5).

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Only hydrogen cyanide and the cyanide ion in solution can be classed as “free” cyanide. The proportions of HCN and CN in solution are according to their equilibrium equation; this is influenced by the solution pH. Methods used to detect free cyanide should not alter the stability of weaker cyanide complexes, as they may otherwise be included in the free cyanide result. Methods used to detect free cyanide should be clear of interferences due to the presence of high concentrations of more stable cyanide complexes or other cyanide forms. If not, the interference must be quantified and allowed for in the result.

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What is the difference between phenol, phenols and phenolics? These terms have often caused confusion in environmental analysis. A phenol (or hydroxybenzene) is a single organic compound. “Phenols” refers to the class of aromatic compounds having a hydroxyl (-OH) group, as well as other substituent groups, on a six-carbon benzene ring or prior to the introduction of the list of priority pollutants in the late 1970’s, to the colorimetric analyses of phenols. “Phenolics” is the title used for the USEPA SW-846 Methods 9065 and 9066 for the colorimetric measurement of numerous known and unknown substances with one or more hydroxyl groups attached to a benzene ring. The organic compound, phenol, is the chemical used to calibrate the colorimetric test for the classes of compounds known as phenols or phenolics.

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