Biochemical oxygen demand calculation

Molecular connectivity indices are desirable as potential explanatory variables because they can be calculated for a nominal cost (fractions of a second by computer) and they describe fundamental relationships about chemical structure. That Is, they describe how non-hydrogen atoms of a molecule are "connected". Here we are most concerned with the statistical properties of molecular connectivity Indices for a large set of chemicals In TSCA and the presentation of the results of multivariate analyses using these Indices as explanatory variables to understand several properties important to environmental chemists. We will focus on two properties for which we have a relatively large data base (1) biodegradation as measured by the percentage of theoretical 5-day biochemical oxygen demand (B0D)( 11), and (2) n-octanol/water partition coefficient or hereafter termed log P (12). 

CATABOL is a knowledge-based expert system for the prediction of biotransformation pathways. It works in tandem with a probabilistic model that calculates the probabilities of the individual transformations and overall biochemical oxygen demand (BOD) and extent of C02 production (Jaworska et al., 2002). The model assesses biodegradation based on the entire pathway and not,... 

Biochemical oxygen demand is calculated by keeping a sample of water containing a known amount of oxygen for five days at 20 °C in the dark. The oxv-gen content is measured again after this time. 

If the biochemical oxygen demand of the settleable solids is to be determined, it may in the case of primary sludge be calculated from the loss on ignition of the settleable solids. According to Imhoff, 30 g organic substances cause 20 g BOD5 in primary sludge. 

Theoretical oxygen demand (TOD) calculated for complete oxidation to carbon dioxide and water. Biochemical oxygen demand (BOD) expressed as a percentage of theoretical oxygen demand (closed bottle test). 

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