The effects of divalent copper on performance, extracellular polymeric substances and microbial community of an anoxic–aerobic sequencing batch reactor

Abstract

The effects of divalent copper (Cu(II)) on the performance, extracellular polymeric substances (EPS) and microbial community of activated sludge were investigated in an anoxic-aerobic sequencing batch reactor (SBR). The removal efficiencies of chemical oxygen demand (COD) and ammonia nitrogen (NH 4 + -N) decreased with the increase of influent Cu(II) concentration from 0 to 50 mg L À1 . The specific oxygen utilization rate (SOUR), specific ammonium oxidation rate (SAOR), specific nitrite oxidation rate (SNOR), and specific nitrate reduction rate (SNRR) decreased with the increase of influent Cu(II) concentration. The protein (PN) contents in the loosely bound EPS (LB-EPS) and tightly bound EPS (TB-EPS) increased from 3.67 and 4.73 mg g À1 VSS to 32.83 and 50.45 mg g À1 VSS with the increase of influent Cu(II) concentration from 0 to 50 mg L À1 , respectively. The polysaccharide (PS) contents in the LB-EPS and TB-EPS increased from 1.44 and 2.68 mg g À1 VSS to 8.51 and 19.84 mg g À1 VSS with the increase of influent Cu(II) from 0 to 50 mg L À1 , respectively. The three-dimensional excitation-emission matrix (3D-EEM) fluorescence spectra and Fourier transform infrared (FTIR) spectra illustrated that the addition of Cu(II) to the influent had distinct effects on the functional groups of PN and PS in the LB-EPS and TB-EPS. The sludge volume index (SVI) showed a negative correlation with LB-EPS (or TB-EPS) content at different Cu(II) concentrations. Some microorganisms adapting to high Cu(II) concentration became predominant bacteria, while others without Cu(II)-tolerance capacity gradually depleted or weakened with the increase in Cu(II) concentration.Fig. 7 DGGE analysis of microbial communities in the SBR at different Cu(II) concentrations. (a) DGGE profiles; (b) cluster analysis based on UPGMA methods. 30744 | RSC Adv., 2015, 5, 30737-30747This journal is

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Effect of oxytetracycline on performance and microbial community of an anoxic–aerobic sequencing batch reactor treating mariculture wastewater

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“…The SOUR, SAOR, SNOR and SNRR of the activated sludge were measured according to Wang et al, 30 with minor modication, on days 25, 50, 73, 95, 130 and 160, corresponding to the OTC concentrations of 0, 2, 4, 8, 10 and 12 mg L À1 , respectively. The SOUR determination was performed in a 500 mL pre-cleaned biological oxygen demand (BOD) bottle with 100 mL activated sludge from the SBR and 400 mL pre-aerated synthetic wastewater.…”

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