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1.
J Hazard Mater ; 416: 125865, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492813

RESUMO

Anaerobic biological treatment technologies are one of the major hotspots of antibiotic resistance genes (ARGs). Previous studies have applied the electrochemical process to improve biogas production, however, it was challenged that high voltages might promote membrane permeability and reactive oxygen species overproduction to promote ARGs proliferation. Herein, the biogas production and ARGs proliferation in an anaerobic electrochemical membrane bioreactor (AnEMBR) were investigated at the gradient voltages of 0-0.9 V. Results show the reactor performances (average CH4 production and current generation) were distinctly improved with the increase of applied voltage, and reached the optimum at 0.9 V. However, long-term application (>30 day) of 0.9 V deteriorated the reactor performances. Meanwhile, the relative abundances of most target ARGs in the supernatant and effluent of AnEMBR at 0.9 V increased by 0.68-1.55 and 0.42-1.26 logs compared to those before applying voltage, respectively. After disconnecting the circuit, these ARGs abundances all decreased to the original level. Significant correlations between intlI and ARGs (e.g., tetA, tetQ, sulI, and sulII) were observed, indicating horizontal gene transfer may contribute to the increased ARGs. Moreover, the shift of microbial communities caused by the applied voltage enriched potential ARGs-hosts (e.g., Tolumonas), contributing to the proliferation of ARGs.


Assuntos
Antibacterianos , Biocombustíveis , Anaerobiose , Antibacterianos/farmacologia , Reatores Biológicos , Proliferação de Células , Resistência Microbiana a Medicamentos/genética , Genes Bacterianos
2.
Chemosphere ; 193: 840-846, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29874757

RESUMO

The presence of antibiotics in wastewater has been widely confirmed. Membrane bioreactor (MBR), as an efficient wastewater treatment technology, has attracted increasing interest in its ability to remove antibiotics in recent years. However, its long-term operation stability and the underlying mechanisms for antibiotics removal are still poorly understood. In this study, a hollow fiber MBR was used to treat low concentration sulfamethazine (SMZ) contained wastewater. The long-term effects of various SMZ concentrations on nutrients removal, SMZ degradation, and sludge characteristics were investigated. During the 244 days operation, the overall SMZ removal efficiency could reach 95.4 ± 4.5% under various SMZ concentrations and hydraulic retention times. The reactor exhibited high chemical oxygen demand and NH4+-N removal efficiencies, which reached 93.0% and 96.2%, respectively. A sludge concentration of 4.1 ± 0.3 g/L was maintained in the system without excess sludge discharge. The dosage of SMZ had obvious effect on sludge characteristics. The contents of extracellular polymeric substances (EPS) in MBR decreased after a long-term operation of the reactor under SMZ pressure. The low sludge concentration and the reduced EPS content were also beneficial for mitigating membrane fouling. Thus, this study provides a low-cost, efficient and simple approach to treat SMZ-contained wastewater.


Assuntos
Reatores Biológicos/normas , Sulfametazina/química , Águas Residuárias/química , Purificação da Água/métodos
3.
Bioresour Technol ; 260: 61-67, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29614452

RESUMO

Recovery of volatile fatty acids (VFAs) from wastewater is an important route for wastewater valorization. Selective acidogenic fermentation enables an efficient production of VFAs from wastewater, whereas electrodialysis (ED) provides an effective approach to concentrate VFAs. However, these two processes have not been coupled in one single system previously. In this study, an acidogenesis-ED integrated system that coupled a continuous acidogenesis with a batch process of VFA concentration was developed for recovery of high-concentration VFAs from wastewater. Under 20.0 V voltage, the acetate was concentrated by 4-fold and the propionate and butyrate were concentrated by over 3-fold in the integrated system after 528-h operation. The declined VFAs recovery ratios at the later stage due to significant reverse diffusion indicate a need to prevent product over-accumulation. This work demonstrated the feasibility of the acidogenesis-ED integrated reactor for wastewater valorization and discussed the remaining challenges and opportunities.


Assuntos
Ácidos Graxos Voláteis , Águas Residuárias , Reatores Biológicos , Ácido Butírico , Fermentação , Concentração de Íons de Hidrogênio , Propionatos , Esgotos
4.
Bioresour Technol ; 247: 471-476, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28968568

RESUMO

In this study, a novel electrodialysis membrane bioreactor was used for EBPR sludge treatment for energy and phosphorus resource recovery simultaneously. After 30days stable voltage outputting, the maximum power density reached 0.32W/m3. Over 90% of phosphorus in EBPR sludge was released while about 50% of phosphorus was concentrated to 4mmol/L as relatively pure phosphate solution. Nitrogen could be removed from EBPR sludge by desalination and denitrification processes. This study provides an optimized way treating sludge for energy production and in situ phosphorus recovery.


Assuntos
Reatores Biológicos , Esgotos , Eletricidade , Nitrogênio , Fosfatos , Fósforo
5.
Sci Rep ; 5: 16281, 2015 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-26541793

RESUMO

Recovering nutrients, especially phosphate resource, from wastewater have attracted increasing interest recently. Herein, an intermittently aerated membrane bioreactor (MBR) with a mesh filter was developed for simultaneous chemical oxygen demand (COD), total nitrogen (TN) and phosphorous removal, followed by phosphorus recovery from the phosphorus-rich sludge. This integrated system showed enhanced performances in nitrification and denitrification and phosphorous removal without excess sludge discharged. The removal of COD, TN and total phosphorus (TP) in a modified MBR were averaged at 94.4 ± 2.5%, 94.2 ± 5.7% and 53.3 ± 29.7%, respectively. The removed TP was stored in biomass, and 68.7% of the stored phosphorous in the sludge could be recovered as concentrated phosphate solution with a concentration of phosphate above 350 mg/L. The sludge after phosphorus release could be returned back to the MBR for phosphorus uptake, and 83.8% of its capacity could be recovered.


Assuntos
Reatores Biológicos , Carbono/isolamento & purificação , Membranas Artificiais , Nitrogênio/isolamento & purificação , Fósforo/isolamento & purificação , Ar , Biofilmes , Esgotos
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