Effects of Exogenous Nutrient Additions on Azodye Wastewater Treatment

Since the azo dyes widely used in textile-dyeing industry are toxic, highly persistent, and ubiquitously distributed in the environment, their treatment efficiencies and fade in ecosystems have received worldwide attention. Due to the microbes play important roles in azo-dye degradation, exogenous nutrient addition is used as a promising biostimulation strategy to improve the treatment efficiencies of azo-dye wastewater. However, little is known about the effects of different kinds of exogenous nutrients on the azo-dye wastewater treatment directly. Here, three kinds of common nutrients, glucose, starch and yeast extract, were added to the sequencing batch reactors （SBR） for the treatment of wastewater containing acid red 73 to compare the biostimulation efficiencies by investigating the dye＇s removal efficiencies and the changes of related water qualities. Our results showed that the reactors added yeast extract had highest removal efficiencies and chemical oxygen demand （COD） as well, followed by glucose and starch. The removal rates of acid red 73 and COD were 90.63% and 8713% in the reactors added yeast extract, respectively, while 86.49% and 78.4% in those with glucose and 85.38% and 75.2% in those with starch. This study provided some useful information for the biostimulation strategy of azo-dye wastewater treatment and preliminarily suggested that yeast extract would be the optimal choice.

Since the azo dyes widely used in textile-dyeing industry are toxic,highly persistent,and ubiquitously distributed in the environment,their treatment efficiencies and fade in ecosystems have received worldwide attention.Due to the microbes play important roles in azo-dye degradation,exogenous nutrient addition is used as a promising biostimulation strategy to improve the treatment efficiencies of azo-dye wastewater.However,little is known about the effects of different kinds of exogenous nutrients on the azo-dye wastewater treatment directly.Here,three kinds of common nutrients,glucose,starch and yeast extract,were added to the sequencing batch reactors(SBR)for the treatment of wastewater containing acid red 73 to compare the biostimulation efficiencies by investigating the dye's removal efficiencies and the changes of related water qualities.Our results showed that the reactors added yeast extract had highest removal efficiencies and chemical oxygen demand(COD)as well,followed by glucose and starch.The removal rates of acid red 73 and COD were 90.63%and 87.3%in the reactors added yeast extract,respectively,while 86.49%and 78.4%in those with glucose and 85.38%and 75.2%in those with starch.This study provided some useful information for the biostimulation strategy of azo-dye wastewater treatment and preliminarily suggested that yeast extract would be the optimal choice.