The transformation and toxicity of anthraquinone dyes during thermophilic (55 degrees C) and mesophilic (30 degrees C) anaerobic treatments.
We studied in batch assays the transformation and toxicity of anthraquinone dyes during incubations with anaerobic granular sludge under mesophilic (30 degrees C) and thermophilic (55 degrees C) conditions. Additionally, the electron shuttling capacity of the redox mediator anthraquinone-2-sulfonic acid (AQS) and subsequent increase on decolourisation rates was investigated on anthraquinone dyes. Compared with incubations at 30 degrees C, serum bottles at 55 degrees C presented distinctly higher decolourisation rates not only with an industrial wastewater containing anthraquinone dyes, but also with model compounds. Compared with batch assays at 30 degrees C, the first-order rate constant "k" of the Reactive Blue 5 (RB5) was enhanced 11-fold and 6-fold for bottles at 55 degrees C supplemented and free of AQS, respectively. However, the anthraquinone dye Reactive Blue 19 (RB19) demonstrated a very strong toxic effect on volatile fatty acids (VFA) degradation and methanogenesis at both 30 degrees C and 55 degrees C. The apparent inhibitory concentrations of RB19 exerting 50% reduction in methanogenic activity (IC50-value) were 55 mg l(-1) at 30 degrees C and 45 mg l(-1) at 55 degrees C. Further experiments at both temperatures revealed that RB19 was mainly toxic to methanogens, because the glucose oxidizers including acetogens, propionate-forming, butyrate-forming and ethanol-forming microorganisms were not affected by the dye toxicity.
dos Santos
André B
AB
Sub-Department of Environmental Technology, Wageningen University, Bomenweg 2, PO Box 8129, 6700EV Wageningen, The Netherlands. andre.dossantos@wur.nl
Bisschops
Iemke A E
IA
Cervantes
Francisco J
FJ
van Lier
Jules B
JB
D000693:Anaerobiosis; D000880:Anthraquinones / Q000737:chemistry / Q000494:pharmacology*; D019149:Bioreactors; D004396:Coloring Agents / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D005232:Fatty Acids, Volatile / Q000378:metabolism; D020128:Inhibitory Concentration 50; D007700:Kinetics; D008697:Methane / Q000032:analysis / Q000378:metabolism; D015394:Molecular Structure; D013696:Temperature; D013783:Textile Industry; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical; D018508:Water Purification / Q000379:methods
D000880:Anthraquinones; D004396:Coloring Agents; D005232:Fatty Acids, Volatile; D014874:Water Pollutants, Chemical; D008697:Methane