Abstract:
Nonylphenol ethoxylates (NPEOs) in textile wastewater can be biodegraded into more estrogenic potent intermediates such as NP during biological treatment, resulting in increased estrogenicity of secondary effluent when compared to the influent wastewater. In order to explore the bioaugmentation effect of bacterial consortium on controlling endocrine disrupting toxicity during textile wastewater treatment, NP10EO and NP were used as the sole carbon source to acclimate textile activated sludge to obtain the corresponding bacterial consortium NPEB and NPB, respectively. Experimental results showed that the 48 h degradation rates of 10 mg/L NP10EO and NP were higher than 98% when degraded with 5 mg/L NPEB and NPB, respectively. Single or combined addition of 5 mg/L NPEB and NPB to 500 mg/L activated sludge significantly improved its degradation performance towards NP10EO at different concentrations (10 mg/L and 1 mg/L), and markedly shortened the time for estrogenicity changing to complete during NP10EO degradation; also, the estrogenicity of the water matrix was maintained at relatively low levels. In contrast, when 1000 mg/L glucose was added into the biodegradation system as an additional carbon source, the bioaugmentation effect of NPB was completely inhibited, whereas NPEB could still improve of performance of activated sludge in degrading NP10EO as well as shorten the time needed for toxicity control even when its degradation ability was inhibited. Analysis of bacterial community structure through 16S rRNA gene showed that the dominant bacteria in NPEB and NPB were
Pseudomonas and
Sphingobium, accounting for more than 50% of the microbiome, which may be the key functional bacteria involved in NP10EO/NP degradation and toxicity control.