Recalcitrance, biodegradation

The advanced oxidation processes offer the possibility for destruction of recalcitrant biodegradable and toxic organic pollutants. The field of applications regarding wastewater treatment varies. AOPs can be applied as ... 

Treatment process for partial oxidation of recalcitrantly biodegradable organic pollutants. Aim is to make this recalcitrantly biodegradable products biodegradable in conventional aerobic and anaerobic wastewater treatment systems... 

Median value from the reported studies Quantitative estimation based on % occurrence of recalcitrance NA Insufficient information NC Not calculable ()u=0) Scale % recalcitrance - biodegradability < 10% - Almost always, 10%-25% - Frequently, 25%-50% - Sometimes, 50%-75% - Barely, >75% - Almost never. [From M.P. Suarez and H.S. Rifai, Bioremediation Journal, 3, 337-362. Copyright 1999 Battelle Memorial Institute. Reprinted with permission.]... 

RDX and HMX are rather more recalcitrant, especially under aerobic conditions, but there are promising indications that biodegradation can occur under some conditions, especially composting (67). Several strains of bacteria able to use RDX (and Triazine) as a sole source of nitrogen for growth have recentiy been isolated, and this is an area where rapid progress is being made. 

CometaboHsm refers to situations where a compound caimot be biodegraded effectively unless another food source is available. The recalcitrant compound, such as TCE, does not provide the energy to allow the microorganisms to grow and thrive. When another food source is available such as... 

Xenobiotic Compound foreign to biological systems. Often refers to human-made compounds that are resistant or recalcitrant to biodegradation and decomposition. 

Fall RR, JI Brown, TL Schaeffer (1979) Enzyme recruitment allows the biodegradation of recalcitrant branched hydrocarbons by Pseudomonas citronellolis. Appl Environ Microbiol 38 715-722. 

Cook AM, R Hiitter (1981) Degradation of 5-triazines a critical view of biodegradation. In Microbial Degradation of Xenobiotics and Recalcitrant Compounds (Eds T Leisinger, AM Cook, R Hiitter, J Niiesch), pp. 237-249. Academic Press, London. 

Neilson AH, A-S Allard, M Remberger (1985) Biodegradation and transformation of recalcitrant compounds. Handb Environ Chem 2C 29-86. 

It is important to be able to assess biodegradation of the oil relative to that of its most recalcitrant components. 

The collective evidence suggests the variable recalcitrance of MTBE under aerobic conditions, a degree of recalcitrance anaerobic conditions, and that the presence of the putative degradation product tert-butanol cannot necessarily be construed as evidence for biodegradation (Landmeyer et al. 1998). Bioremediation of groundwater contaminated with MTBE is clearly beset with problems for its practical implementation. 

As wastewater from resin-producing factories contains recalcitrant compounds, the removal efficiencies achieved by means of the nitrification-denitrification systems could not reach the required disposal values and a posttreatment, such as ozonation, would be necessary to enhance the biodegradability of those compounds.2 53... 

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