EFFECTS OF TRACE CHROMIUM(VI) ON DOMINANT MICROORGANISMS AND THE STABILITY OF AEROBIC GRANULAR SLUDGE

摘要

In this study, an aerobic granular sludge (AGS) was cultivated successively in a column sequencing batch reactor (SBR) with glucose and sodium acetate as the carbon sources. The long-term effects of trace Cr(VI) concentrations (0.00, 0.05, 0.15, 0.30, and 0.50 mg/L) on the dominant microorganisms, and on the stability of aerobic granular sludge are discussed. The results showed that Cr(VI) at concentrations of 0.05 and 0.15 mg/L can promote the growth of aerobic granular sludge, while the dominant microorganisms and AGS stability were adversely affected at Cr(VI) concentrations of 0.30 and 0.50 mg/L. When the Cr(VI) concentration increased to 0.30 and 0.50 mg/L, the dominant microorganisms were converted from cocci and bacilli to filamentous bacteria. The PN/PS ratio declined sharply at 0.30 and 0.50 mg/L Cr(VI), which may have influenced the stability of the AGS. The functional groups -NH_2 and -OH can form ionic bonds with Cr(VI). A new FTIR spectral band at 1733 cm~(-1) was observed at 0.15, 0.30, and 0.50 mg/L Cr(VI), which might suggest that some new metal complexes promoted the hydrolysis of peptide bonds, producing asymmetrical stretching of C=O.