Effect of Copper (II) on the Characteristics of Aerobic Granules

Abstract

Aerobic granules were cultivated successively in column sequencing batch reactor (SBR) with the glucose as carbon source. The effect of copper (II) on the characteristics of aerobic granules was studied. Results showed that the physical, morphology and extracellular polymeric substances (EPS) of aerobic granules were influenced in different degree under different concentrations of copper (II) in sequencing batch reactor (SBR). The appropriate Cu2+ can be adsorbed by the microorganisms in aerobic granules under the functions of chelation and displacement of heavy metals. Under the Cu2+ concentration of 0.5～3.0mg/L, the stable MLSS and better settleable granules with higher S.G. and lower SVI can been attained in the reactors. The sludge can maintain the granules in stable till the Cu2+ concentration increases to 20.0mg/L. The ratios of EPSC/EPN distribute in 6.60～7.01 steadily under the Cu2+ concentration of 0.5～10.0mg/L.However, excess Cu2+ can destroy the metabolism balance of the microorganisms and the protein synthesization and genetic information transportation are baffled. When the Cu2+ concentration increase to 50mg/L, more filamentous appears in the granules and the compact granules change to in disperse. The ratios of EPSC/EPN evidently rise to 7.59 and 7.46 respectively under high Cu2+ concentration of 20.0mg/L and 50.0mg/L. It suggests that the microorganisms try to excreting more EPS and protecting itself from the environmental change.

Elemental distribution of latex‐based aerobic granules and its effects on micromorphological properties and settling performance

“…The elemental analysis of latex granules (Exhibit 4) indicates the significant presence of zinc, aluminum, titanium, and calcium. Zheng et al (2013) proved that increasing zinc concentration helps to stabilize the granules but very high zinc concentration would cause the granules to disperse and become loosely bound flocs. Thus, it can be suggested that the loose granular structure may be due to the effect of the high zinc concentration found in the granules.…”

The effect of divalent and trivalent cations on aggregation and surface hydrophobicity of selected microorganism

“…Glucose (0.5 g/L), ethanol (0.125 g/L), and sodium acetate (0.5 g/L) were used as the mixed carbon sources. The trace elements used in this study were based on the composition recommended by Zhang et al [24].…”

“…A stock solution of 100 g/L was prepared for each cation and the working concentrations were prepared daily by means of dilution. The experimental conditions for cationic concentration and SHb during the initial cell interaction of the biogranulation pocess was based on previous study [25,31,[36][37]. All cation solutions were sterilized at 121˚C for 5 min [36] as shown in Table 1.…”

“…Several efforts have been made to enhance granulation with additives and change the start up or operating conditions either in aerobic or anaerobic systems [12]. Some of the notable additives are cations [22][23][24][25][26] and synthetic polymers [27][28][29]. Cations can facilitate the bridging of the negatively charged groups on the cell surface with the secreted EPS [23,[30][31].…”