Waste sludge has been widely exploited as a potential pool for resources. Meantime, it has also been regarded as a tremendous reservoir of accumulated contaminants, such as antibiotic resistances genes (ARGs). However, to date, researchers paid little attention to the simultaneous recovery of valuable resources and removal of ARGs. Here we reported that alkaline fermentation of sludge at pH 10, significantly increased the production of volatile fatty acids (VFAs) from sludge, which, however, effectively removed sulfonamide and tetracycline resistance genes. Compared with the control, sludge fermentation at pH 10 increased the yield of VFAs by 5 folds, but reduced the abundances of target ARGs by 0.87 (sulI), 1.36 (sulII), 0.42 (tet(O)), 1.11 (tet(Q)), 0.79 (tet(C)) and 1.04 (tet(X)) log units. Further mechanism studies revealed that the pH 10 condition promoted the hydrolysis of sludge, but inhibited the methane generation process. Besides, the high pH not only shifted the community structures of sulfonamide and tetracycline resistant bacteria, but also significantly decreased their abundances, restricting the potential ARGs hosts. Moreover, alkaline fermentation remarkably decreased the quantities and the ARGs-possessing ability of genetic vectors (plasmid DNA, extracellular DNA and phage DNA), which might limit the transfer of ARGs via conjugation, transformation and transduction. Collectively, our results suggest that alkaline fermentation might be a promising process for simultaneous recovery of carbon source and removal of ARGs from waste sludge.

Alkaline fermentation effectively enhances the recovery of carbon source and removal of antibiotic resistance genes from waste sludge

254th National Meeting (2017)

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