Roles of EDTA washing and Ca 2+ regulation on the restoration of anammox granules inhibited by copper(II)

Extraction, recovery and characterization of structural extracellular polymeric substances from anammox granular sludge

“…Up to now, comprehensive studies have stated the sensitivity of biomass to the presence of toxic compounds. These toxic compounds include emerging contaminants (e.g., Tetracycline (TC) (Shi et al, 2013), Bisphenol A (BPA) (Li et al, 2015b), 4-chlorophenol (4-CP) (Wei et al, 2015b)), nanoparticles (NPs) (He et al, 2020;Li et al, 2015a;Mu et al, 2012) and heavy metals (Zhang et al, 2016b), which are closely associated with the granular stability. As shown in Fig.…”

“…For TB-EPS, there was no C-H bending vibration band, whilst the bands of amide I and C-H stretching vibration were enhanced. In addition to the protective roles of EPS matrix, Zhang et al (2016b) pointed out that many negatively charged functional groups (-COOH, -OH, etc.) in EPS may electrostatically attract Cu 2+ , by this the electrostatic repulsive force of granules would accordingly decrease.…”

“…Mineral cations not only are essential for metabolism for microorganisms, but potentially stimulate the granule formation and bacterial restoration in damaged or suppressed biological systems. Among the cations, Calcium ions (Ca 2+ ) are one key parameter for granular formation (Liu et al, 2020), the activity restoration (Zhang et al, 2016b), and bioprocess improvement (Ma et al, 2020), thus resulting in the variation of EPS components and characterisations. For example, Ma et al (2020) observed a high level of Ca 2+ (1000-2000 mg/L) not only caused the change of functional groups of AnGS-derived EPS, but simultaneously enhanced EPS production and anaerobic sludge digestion.…”

“…This finding may attribute to stability damage resulted from the Ca 2+ addition, leading to microbial consortia to produce more biopolymers against the inhibited situation. Also, Ca 2+ was reported to play an important role for destructed anammox cells to restore their metabolic growth (Zhang et al, 2016b). Liu et al (2020) proposed a strategy by combining an external conditioning step with Ca 2+ addition before reintroducing effluent sludge into SBR, which led to an increased EPS yield and an acceleration of AGS formation.…”

Comparative evaluation of short-term stress of Cd(II), Hg(II), Pb(II), As(III) and Cr(VI) on anammox granules by batch test

“…For example, liquid Cd(II) concentration with an initial value of 20 mg/L transferred to 0.28 mg/L, equaling to a reduction of 98.55%. Moreover, metal inhibition is primarily a physicochemical rather than a biological transport process because sorption plays a vital role in metal uptake (25). To investigate the correlativity between metal inhibition and biomass adhesion, biomass metal concentration was determined, as illustrated in Fig.…”