Solids, biodegradability tests

Activated vermicuhte was found to be a suitable solid matrix for conducting biodegradability testing.Vermicuhte by itself does not affect biological growth but can be activated to perform tasks typicahy associated with mature compost which is a very complex, difficult to standardize biological mixture. 

Figure 21.9 Biodegradability testing of solid polymers [ItavaaraSc Vikman, as cited in 50 51].

HD values were synthesized by controlled acetylation of commercial PVA (HD = 99%) and submitted to biodegradation tests in aqueous medium, mature compost and soil by using respirometric procedures [121]. Reacetylated PVA samples characterized by HD of between 25 and 75% underwent extensive mineiahzation when buried in solid media, while PVA (HD = 99%) showed recalcitrance to biodegradation under those conditions. An opposite trend was observed in aqueous solution, in the presence of PVA-acclimated microorganisms. In... 

A new biodegradation test method for bioplastics was first developed at ASTM level as ASTM D5511-94. Later, in 2004, the same method was published as ISO 15985-Plastics - Evaluation of the ultimate anaerobic biodegradability and disintegration under high solids anaerobic digestion conditions Method by analysis of released biogas. 

A preliminary test for the biodegradability of the 3-phenyl- and 3-carbamoyl-2(lH)pyridones was conducted in a barnyard humus suspension. The analysis by HPLC showed some loss, and the fluorescent compounds seemed to be adsorbed onto the solid. The 3-carbamoyl-2(lH)pyridone (II) also hydrolyzed to 3-carboxylic acid-2(lH)pyridone both in the slurry test and in water solutions that had been left standing 1-2 weeks. In preliminary tests both the 3-phenyl- and the 3-carbamoyl-2(lH)pyridones apparently adsorbed to some extent on silica sand columns. In addition, the solubility of both 1-H compounds was somewhat low, 1.3 x 10 M for II, and 1.0 x 10 M for IV. 

The biodegradation of branched-chain alkanol ethoxyethylates was carried out by the standard OECD confirmatory tests and the metabolites fractionated after solid-phase extraction. The structures of the metabolites were determined by electrospray mass spectrometry and this made it possible to derive a scheme for the partial degradation of the compounds (Di Corcia et al. 1998). 

Wash effluents from nitration installation can cause problems due to the high nitrophenol concentrations, their high toxicity to sewage bacteric and their general resistance to biodegradation. Electrochemical pretreatment tests in the laboratory showed a reduction in toxicity, and improvement of the color smell, etc. The electrochemical pretreatment is also attractive because of the absence of solid waste coproducts and its ease of operational control, [135]. 

Shake flasks were inoculated with mixed liquor suspended solids from activated sludge units in a Houston area domestic waste sewage treatment plant. Initial surfactant concentrations were 20 mg/ . CO2 formed from biodegradation was trapped in aqueous Ba(OH)2. The amount of CO2 formed was determined by back-titrating residual Ba(OH)2 with HCl at the end of each test period. Glucose was included as a positive biodegradation standard. 

Three field demonstrations of PCB biodegradation approaches are currently being tested at a natural gas pipeline site in Pennsylvania (Envirogen, Inc.) in situ aerobic biotreatment (solid phase land treatment landfarming ) aerobic soil slurry biotreatment and in situ anaerobic biotreatment. These studies are being conducted over a two-year time frame and will be completed by early 1996. Preliminary results are presented below. 

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