Organic matter degradation, effects

In general, oil and organic matter that degrade or deposit will produce undesirable effects in boilers. The levels of these contaminants in FW should be minimized. Oils that do not volatilize at the operating pressure should be eliminated from the FW (e.g., steam condensate that could be contaminated with these low volatility materials should not be used in FW). 

Fig. 16.2 Degradation rate constant for methyl parathion as a function of pH, in aqueous 5.0 mM hydrogen sulfide with and without natural organic matter (NOM), at 25°C. Reprinted with permission from Guo XF, Jans U (2006) Kinetics and mechanism of the degradation of methyl parathion in aqueous hydrogen sulfide solution Investigation of natural organic matter effects. Environ Sci Technol 40 900-906. Copyright 2006 American Chemical Society...

Guo XF, Jans U (2006) Kinetics and mechanism of the degradation of methyl parathion in aqueous hydrogen sulfide solution Investigation of natural organic matter effects. Environ Sci Technol 40 900-906... 

In slow filtration, much of the effect is obtained by the formation of a filtration layer, including the substances that are extracted from the water. At the early stages of the operation, these substances contain microorganisms able to effect, beyond the filtration, biochemical degradation of the organic matter. This effect also depends on the total surface of the grains forming the filter material. The probability of contact between the undesirable constituents of the water and the surface of the filter medium increases in proportion to the size of the total surface... 

Stable metabolic associations generally between pairs of anaerobic bacteria have been termed syntrophs, and these are effective in degrading a number of aliphatic carboxylic acids or benzoate under anaerobic conditions. These reactions have been discussed in reviews (Schink 1991, 1997 Lowe et al. 1993) that provide lucid accounts of the role of syntrophs in the degradation of complex organic matter. Two examples are given here to illustrate the experimental intricacy of the problems besetting the study of syntrophic metabolism under anaerobic conditions ... 

Greer LE, DR Shelton (1992) Effect of inoculant strain and organic matter content on kinetics of 2,4-dichlorophenoxyacetic acid degradation in soil. Appl Environ Microbiol 58 1459-1465. 

Chen, F., Yang, X., Xu, F., Wu, Q., and Zhang, Y. (2009) Correlation of photocatalytic bactericidal effect and organic matter degradation ofTi02. Parti observation of phenomena. Environmental Science and Technology,... 

A mixture of hydrogen peroxide and ferrous iron is effective for color and COD removal of dye effluent, which is effective for complete color removal and partial degradation of organic matter. 

Simple organic molecules such as small carboxylic acids (oxalate, acetate, malonate, citrate, etc.), amino acids and phenols are all ligands for metals. Such compounds may all occur as degradation products of organic matter in natural waters. The complexes formed are typically charged hydrophilic complexes. The stability of the metal complexes with these ligands is, however, moderate in most cases. Model calculations including such compounds at realistic concentrations indicate that their effects on speciation are relatively small [29],... 

Due to its gaseous nature it may have an effect on the stratospheric ozone layer [281, 402, 404]. After injection into soil for fumigation, methyl bromide rapidly diffuses through the soil pore space to the soil surface and then into the atmosphere [159,162,163,405,406]. Since a plastic sheet typically covers the soil surface, the rate of emission into the atmosphere depends upon the thickness and density of the plastic, if other conditions are the same [159, 406]. Other routes of disappearance from soil include chemical hydrolysis, methylation to soil organic matter through free radical reactions, and microbial degradation [ 136,159,405,407]. Several reports appeared on the study of the microbial transformations of methyl bromide, summarized as follows ... 

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