Notice of RetractionPowdered activated carbon (PAC) addition for enhancement of aerobically grown microbial granules treating landfill leachate

Notice of Retraction

After careful and considered review of the content of this paper by a duly constituted expert committee, this paper has been found to be in violation of IEEE´s Publication Principles.

We hereby retract the content of this paper. Reasonable effort should be made to remove all past references to this paper.

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Two laboratory scale SBRs (R1 and R2) were set up to cultivate aerobic granules with landfill leachate. 1 g L^-1 powdered activated carbon (PAC) was added into R1 at the beginning to investigate the effects of PAC on aerobic granulation and stability of granular system. Added PAC acted as precursors (carriers or nuclei) for initial aerobic granulation; it also contributed to a higher hydrodynamic shear force of system, thus significantly promoted granule formation through improving structural integrity and enhancing the granule strength. The final stable granules in R1 were dense and compact, with the mean size of 0.45-0.60 mm and wet density of 1.06 g cm^-3. The PAC-enhanced granules also exhibited high activity, excellent settling ability, high extracellular protein contents, and much improved capability and stability to withstand high organic loadings. In contrast, granules in R2 with no added PAC formed earlier and achieved a larger size, but they had a loose and fluffy structure, and were fragile.