Steel pickling rinse wastewater treatment by two-stage MABR system: Reactor performance, extracellular polymeric substances (EPS) and microbial community

Responses of the microbial community and the production of extracellular polymeric substances to sulfamethazine shocks in a novel two-stage biological contact oxidation system

“…However, the variation trend in TB-EPS was opposite to that in LB-EPS, which may be because SMZ could migrate into the activated sludge by dynamically complexing with EPS. TB-EPS plays a central role in the protection of microbial cells, which can bind with antibiotics and secrete active enzymes for the removal of antibiotics, which then can alleviate cellular osmotic pressure imbalance (Sun et al, 2022 ). Furthermore, as the first barrier of microbial cells, EPS also contacts directly with SMZ in aqueous environments (Guo et al, 2020 ) and plays a key role in the biosorption of SMZ (Wang et al, 2018 ), further reducing it to undetectable levels in the effluent (Xu and Sheng, 2020 ).…”

Salinity stress results in ammonium and nitrite accumulation during the elemental sulfur-driven autotrophic denitrification process

“…PN is usually considered a hydrophobic substance crucial for resisting external osmotic pressures and improving sludge performance (Han et al, 2018). Previous studies found that microorganisms in the system secrete more PN under salinity stress (Lin et al, 2022;Sun et al, 2022). This is because the amino and carboxyl groups in PN increase the hydrophobicity of the cell surface, which helps to maintain the structure and stability of the biofilm (Wang et al, 2013;He et al, 2019).…”

Partial nitrification/ANAMMOX (PN/A) membrane aerated biofilm reactor (MABR) under a low C/N ratio and metagenomics identification

“…DB utilize organics resulting in varying alkalinities. Reducing 1 mole of nitrate to dinitrogen produces 1 mole of hydroxide eqn (6). The alkali production process was expectedly weaker than the acid production process because there was just a little COD in the reactor.…”

“…4 Ammonia-oxidizing bacteria (AOB), ammonia-oxidizing archaea (AOA), ANAMMOX bacteria, nitrite-oxidizing bacteria (NOB), and denitrifying bacteria (DB) can keep in close touch with extracellular polymeric substances (EPSs) and quorum sensing (QS) factors to synergize nitrogen removal in a MABR. [5][6][7] The substrates diffuse from the wastewater to the biofilm, and oxygen diffuses from the hollow membrane to the biofilm, forming a counter-diffusion phenomenon in the MABR, which can improve the nitrogen removal efficiency. [8][9][10] In the recent 20 years, the ANAMMOX process as the most economical and efficient nitrogen removal process has been widely studied.…”