Effect of simulated dyeing wastewater on microbial domestication and community composition

Abstract

In order to explore the selectivity of salt-containing printing and dyeing wastewater to microbial community, the adaptive mechanism of activated sludge to printing and dyeing wastewater was analyzed through the change of microbial community. The activated sludge was domesticated by using different concentrations of neutral dark yellow dye GL and salt inorganic gradient. The degradation efficiency of COD and NH4+-N by the sludge was then determined. Moreover, the microbial community structure under different salinity and dye concentrations was studied by high-throughput sequencing. The results show that when the salinity is 1%, the removal rates of COD and NH4+-N in wastewater reached 91.9% and 94% respectively. When the salinity was more than 1%, the degradation efficiency of sludge to wastewater decreased continuously. The stability of the reactor was obviously reduced with the addition of dye, but the COD removal rate increased with the acclimation of the activated sludge. With the increase of salinity, the microbial diversity gradually decreased, and the dominant position of saprolegniaceae bacteria in the system was gradually replaced by saccharomonas. After adding dyes and continuously increasing the concentration, we found that Bryococaus gradually became the absolutely dominant bacteria family in the activated sludge.

Keywords

• activated sludge
• salinity
• printig and dyeing wastewater
• synergistic domestication
• microbial community