Linear anionic surfactant (SDBS) destabilized anammox process through sludge disaggregation and metabolic inhibition

The increase of emerging contaminants, such as surfactants, is one of the major challenges to biological wastewater treatment. However, the potential impact of linear alkylbenzene sulphonates (LAS), a major class of anionic surfactants, on anammox process is unclear. The long-term effects of sodium dodecyl benzene sulfonate (SDBS, as a model LAS) on reactor performance, microbial community and sludge properties were investigated in this study. The presence of 5 mgL(-1) SDBS promoted the release of extracellular microbial products from anammox granules and the wash-out of anammox population via effluent. Despite sludge disaggregation, the reactor performance was robust to the exposure of 5 mg L-1 SDBS due to functional redundancy. With the further increase of SDBS to 10 mg L-1, the metabolic activity of anammox biomass and the transcription and post translation of hydrazine dehydrogenase were significantly decreased. The potential mechanism might be associated with the damage on cell membrane that induced the leakage of intracellular matrix. These results highlight the need to consider the potential risk of LAS to operation of anammox process in biological wastewater treatment plant.

Automated summary

The study revealed that increasing the concentration of SDBS in the reactor can promote the release of extracellular microbial products from anammox granules and the wash-out of anammox population, affecting reactor performance to some extent. However, functional redundancy in the reactor helps to maintain stable performance despite sludge disaggregation. Furthermore, as the SDBS concentration increases, the metabolic activity of anammox biomass significantly decreases, possibly due to cell membrane damage causing intracellular matrix leakage.