Enhanced anaerobic degradation of BTEX in cabin-washing wastewater using iron-carbon composites

The management and treatment of cabin-washing wastewater has received increasing attention in China. To improve the anaerobic degradation of benzene, toluene, ethylbenzene, and xylenes (BTEX) in cabin-washing wastewater, the addition of iron-carbon composite was adopted to enhance the efficiency of anaerobic digestion by facilitating direct interspecies electron transfer (DIET). The preparation of iron-carbon composite was optimized and its effects on BTEX removal and methanogenic performance were then investigated. The results showed that the iron-carbon composite facilitated the hydrolysis and acidification process. The toluene removal rate was improved by 69.9 %, and the cumulative methane yield was enhanced by 90.5 % under the optimized condition of pyrolysis temperature of 600 °C, Fe/C mass ratio of 1.0 and dosage of 2.5 g/L. Furthermore, both extracellular electron transfer (EET) and intracellular electron transfer (IET) were found enhanced, and the aromatic compound-degrading bacteria was enriched by iron-carbon composite. The enhanced anaerobic degradation of BTEX by iron-carbon composite provided a novel means for the removal of BTEX from cabin-washing wastewater.