Endocrine disrupting chemicals removal in an aerobic granular sludge reactor treating simulated saline wastewater

The occurrence of Endocrine disrupting chemicals (EDCs) in the environment is a topic of concern. It is commonly accepted that the major source of EDCs to the environment is wastewater treatment plants effluents. Salinity is an additional common stress factor in wastewater treatment. Aerobic granular sludge (AGS) has a number of properties that make it more attractive than conventional biological systems for treatment of wastewater containing EDCs. In the present study, an AGS sequencing batch reactor adapted to salinity was operated for 140 days for treating synthetic saline wastewater containing 17β–estradiol (E2), 17α–ethinylestradiol (EE2) and bisphenol-A (BPA). E2 was removed by biodegradation. EE2 adsorption/desorption to the aerobic granules was observed. The increasing of BPA removal efficiency after bioaugmentation with a degrading bacterial strain shows that biodegradation was the removal mechanism. COD removal was not significantly affected by EDCs shock loads. Activity of ammonia oxidizing bacteria and nitrite oxidizing bacteria did not seem to be inhibited by the presence of EDCs. The activity of phosphate accumulating organisms was affected.info:eu-repo/semantics/publishedVersio

Effect of different salt adaptation strategies on the microbial diversity, activity, and settling of nitrifying sludge in sequencing batch reactors

The effect of salinity on the activity of nitrifying bacteria, floc characteristics, and microbial community structure accessed by fluorescent in situ hybridization and polymerase chain reaction–denaturing gradient gel electrophoresis techniques was investigated. Two sequencing batch reactors (SRB1 and SBR2) treating synthetic wastewater were subjected to increasing salt concentrations. In SBR1, four salt concentrations (5, 10, 15, and 20 g NaCl/L) were tested, while in SBR2, only two salt concentrations (10 and 20 g NaCl/L) were applied in a more shock-wise manner. The two different salt adaptation strategies caused different changes in microbial community structure, but did not change the nitrification performance, suggesting that regardless of the different nitrifying bacterial community present in the reactor, the nitrification process can be maintained stable within the salt range tested. Specific ammonium oxidation rates were more affected when salt increase was performed more rapidly and dropped 50% and 60% at 20 g NaCl/L for SBR1 and SBR2, respectively. A gradual increase in NaCl concentration had a positive effect on the settling properties (i.e., reduction of sludge volume index), although it caused a higher amount of suspended solids in the effluent. Higher organisms (e.g., protozoa, nematodes, and rotifers) as well as filamentous bacteria could not withstand the high salt concentrations

Rhodococcus sp. ED55: a bacterial strain with ability to degrade endocrine disrupting chemicals and potential for bioaugmentation

The occurrence of Endocrine disrupting chemicals (EDCs) in the environment is a topic of concern. It is commonly accepted that the major source of EDCs to the environment is wastewater treatment plants (WWTPs’) effluents, due to the inefficiency of WWTPs to remove this kind of pollutants. A bacterial strain – Rhodococcus sp. ED55 was isolated from the sediments of a discharge point of a WWTP in Coloane, Macau, for its ability to degrade EDCs. The bacterium was able to biodegrade 17β–estradiol (E2), 17α–ethinylestradiol (EE2), bisphenol-A (BPA) and bisphenol-S (BPS) at different extents. Strain ED55 was able to completely degrade the supplied amount of E2 in few hours, both in synthetic medium and in real wastewater from a municipal WWTP (Parada, Maia – Portugal). Estrone (E1), 4OH-E1 and 4OH-E2 were identified as intermediate degradation metabolites and the metabolic pathway is under elucidation. Bioaugmentation with Rhodococcus sp. ED 55 significantly improved the natural attenuation of the compound in municipal wastewater in batch assays. The acute test with luminescent marine bacterium Vibrio fischeri revealed elimination of the toxicity of the treated effluent and the standardized yeast estrogenic (S-YES) assay with the recombinant strain of Saccharomyces cerevisiae revealed decrease of estrogenic activity of samples. Rhodococcus sp. ED55 was applied in a strategy of an AGS sequencing batch reactor adapted to salinity, which was operated for treating a synthetic saline wastewater containing E2, EE2 and BPA. E2 was no longer detected in the bulk liquid after 10 min of aerobic reaction throughout reactor operation, suggesting that this compound was quickly removed by biodegradation. EE2 adsorption/desorption to the aerobic granules was observed. Removal of BPA significantly increased after bioaugmentation with Rhodococcus sp. ED55, showing that biodegradation was the governing removal mechanism. COD removal was not significantly affected by EDCs shock loads. Rhodococcus sp. ED55 can potentially be applied in bioaugmentation strategies for ameliorating treatment of wastewater contaminated with EDCs.info:eu-repo/semantics/publishedVersio

Bacterial strain rhodococcus sp. ED55 degrades endocrine disrupring chemicals in wastewater

info:eu-repo/semantics/publishedVersio

Rhodococcus sp. ED55: a bacterial strain with potential for application in wastewater treatment for effective removal of endocrine disruptors

info:eu-repo/semantics/publishedVersio

Treatment of a simulated textile wastewater containing the Reactive Orange 16 azo dye by a combination of ozonation and moving-bed biofilm reactor: evaluating the performance, toxicity, and oxidation by-products

In this study, an aqueous solution containing the azo dye Reactive Orange 16 (RO16) was subjected to two sequential treatment processes, namely: ozonation and biological treatment in a moving-bed biofilm reactor (MBBR). The most appropriate ozonation pretreatment conditions for the biological process and the toxicity of the by-products resulting from RO16 ozone oxidation were evaluated. The results showed that more than 97 % of color removal from the dye solutions with RO16 concentrations ranging from 25 to 100 mg/L was observed in 5 min of ozone exposure. However, the maximum total organic carbon removal achieved by ozonation was only 48 %, indicating partial mineralization of the dye. Eleven intermediate organic compounds resulting from ozone treatment of RO16 solution were identified by LC/MS analyses at different contact times. The toxicity of the dye-containing solution decreased after 2 min of ozonation, but increased at longer contact times. The results further demonstrated that the ozonolysis products did not affect the performance of the subsequent MBBR, which achieved an average chemical oxygen demand (COD) and ammonium removal of 93 ± 1 and 97 ± 2 %, respectively. A second MBBR system fed with non-ozonated dye-containing wastewater was run in parallel for comparison purposes. This reactor also showed an appreciable COD (90 ± 1 %) and ammonium removal (97 ± 2 %), but was not effective in removing color, which remained practically invariable over the system. The use of short ozonation times (5 min) and a compact MBBR has shown to be effective for the treatment of the simulated textile wastewater containing the RO16 azo dye

REMOÇÃO DO CORANTE LARANJA REATIVO 16 POR OZONIZAÇÃO E SISTEMA COM BIOFILME, IDENTIFICAÇÃO DOS PRODUTOS E AVALIAÇÃO DA TOXICIDADE

Neste trabalho foi estudada a ozonização seguida de um MBBR para tratar um efluente contendo o corante Laranja Reativo 16 (LR16). Descoloração completa foi atingida para concentrações de LR16 de 25 a 500 mg/L. Os testes de toxicidade (Microtox) indicaram a formação de produtos menos tóxicos para 2 min de ozonização, seguindo tendência de aumento da toxicidade para tempos superiores. O desempenho do MBBR, entretanto, não foi afetado. Para 25 a 200 mg/L de LR16, a remoção média de DQO e amônio foi superior a 89±1% e 95±1%, respectivamente. Para 500 mg/L de LR16, observou-se queda na remoção de amônio, seguida por rápida adaptação. A remoção de DQO também caiu, devido à formação de intermediários pouco biodegradáveis. Foram identificados 14 produtos de ozonização e verificou-se que parte deles foi metabolizada no MBBR