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1.
N Biotechnol ; 36: 42-50, 2017 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-28126513

RESUMO

In this study, the deterioration of the typical EBPR (Enhanced Biological Phosphorus Removal) process due to the simultaneous presence of electron donor (external substrate) and electron acceptor (oxygen or nitrate) was investigated by using a PAOs (Polyphosphate Accumulating Organisms)-enriched biomass grown in a modified DEPHANOX system. Intracellular and extracellular constituents were monitored in batch tests under different electron donor and acceptor conditions and specific oxygen and nitrogen uptake rates were evaluated. Results showed that phosphorus uptake was inhibited during the simultaneous presence of electron donor (acetate) and acceptor (O2/NO3-) in the mixed liquor. In the presence of acetate, PHAs and glycogen were produced under both aerobic and anoxic conditions irrespectively to the PHAs amount already stored intracellularly. The Krebs cycle reactions and oxidative phosphorylation provided the reduced coenzymes and energy required for PHAs synthesis when biomass polyphosphate content was low. On the contrary, polyphosphate cleavage provided the ATP required for PHAs synthesis in the presence of high biomass polyphosphate content. Inhibition of the respiratory chain reactions was observed when biomass with high polyphosphate and low PHAs content was subjected to simultaneous presence of electron donor and acceptor. PHAs utilization rather than glycogen degradation appears to favor phosphate accumulation since no polyphosphate synthesis occurred in the absence of PHAs reserves.


Assuntos
Transporte de Elétrons , Fósforo/isolamento & purificação , Fósforo/metabolismo , Ácido Acético/metabolismo , Aerobiose , Anaerobiose , Biomassa , Reatores Biológicos , Biotecnologia , Biotransformação , Cinética , Nitratos/metabolismo , Oxigênio/metabolismo , Poli-Hidroxialcanoatos/metabolismo , Polifosfatos/metabolismo , Esgotos/química , Eliminação de Resíduos Líquidos , Águas Residuárias/química
2.
Water Sci Technol ; 69(8): 1612-9, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24759519

RESUMO

A novel enhanced biological phosphorus removal (EBPR) system, which combined the intermittent feeding design with an anaerobic selector, was examined using on-line oxidation reduction potential (ORP), nitrate and ammonium probes. Two experimental periods were investigated: the aerobic and anoxic phases were set at 40 and 20 minutes respectively for period I, and set at 30 and 30 minutes for period II. Chemical oxygen demand (COD), biochemical oxygen demand (BOD5) and P removal were measured as high as 87%, 96% and 93% respectively, while total Kjeldahl nitrogen (TKN) and NH4(+) removal averaged 85% and 91%. Two specific denitrification rates (SDNRs), which corresponded to the consumption of the readily biodegradable and slowly biodegradable COD, were determined. SDNR-1 and SDNR-2 during period I were 0.235 and 0.059 g N g(-1) volatile suspended solids (VSS) d(-1) respectively, while the respective rates during period II were 0.105 and 0.042 g N g(-1) VSS d(-1). The specific nitrate formation and ammonium oxidizing rates were 0.076 and 0.064 g N g(-1) VSS d(-1) for period I and 0.065 and 0.081 g N g(-1) VSS d(-1) for period II respectively. The specific P release rates were 2.79 and 4.02 mg P g(-1) VSS h(-1) during period I and II, while the respective anoxic/aerobic uptake rates were 0.42 and 0.55 mg P g(-1) VSS h(-1). This is the first report on an EBPR scheme using the intermittent feeding strategy.


Assuntos
Reatores Biológicos , Fósforo/química , Eliminação de Resíduos Líquidos/métodos , Aerobiose , Projetos Piloto
3.
Water Environ Res ; 84(6): 475-84, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22866388

RESUMO

Enhanced Biological Phosphorus Removal (EBPR) under anoxic conditions was achieved using a Biological Nutrient Removal (BNR) system based on a modification of the DEPHANOX configuration. Double-probe Fluorescence in Situ Hybridization (FISH) revealed that Polyphosphate Accumulating Organisms (PAOs) comprised 12.3 +/- 3.2% of the total bacterial population in the modified DEPHANOX plant. The growing bacterial population on blood agar and Casitone Glycerol Yeast Autolysate agar (CGYA) medium was 16.7 +/- 0.9 x 10(5) and 3.0 +/- 0.6 x 10(5) colony forming units (cfu) mL(-1) activated sludge, respectively. A total of 121 bacterial isolates were characterized according to their denitrification ability, with 26 bacterial strains being capable of reducing nitrate to gas. All denitrifying isolates were placed within the alpha-, beta-, and gamma-subdivisions of Proteobacteria and the family Flavobacteriaceae. Furthermore, a novel denitrifying bacterium within the genus Pseudomonas was identified. This is the first report on the isolation and molecular characterization of denitrifying bacteria from EBPR sludge using a DEPHANOX-type plant.


Assuntos
Bactérias/classificação , Bactérias/metabolismo , Reatores Biológicos , Desnitrificação/fisiologia , Fósforo/metabolismo , Eliminação de Resíduos Líquidos/métodos , Anaerobiose , Bactérias/genética , Biomassa , Oxigênio , Fósforo/química , Filogenia , Poluentes Químicos da Água/química , Poluentes Químicos da Água/metabolismo
4.
J Biosci Bioeng ; 111(2): 185-92, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21056003

RESUMO

Enhanced biological phosphorus removal (EBPR) is a widely applied method for nutrients removal, although little is known about the key genes regulating the complex biochemical transformations occurring in activated sludge during phosphorus removal. In the present study, the nitrite reductase gene (nirS) diversity and the denitrifying polyphosphate accumulating organisms (DPAOs) population, grown in a bench scale, two-sludge, continuous flow plant, operating for biological anoxic phosphorus removal (DEPHANOX-type), fed with municipal wastewater, were examined by means of physicochemical analyses and the application of molecular techniques. The DEPHANOX configuration highly influenced biomass phosphorus as well as polyhydroxyalkanoates content and facilitated the enrichment of the DPAOs population. The application of double probe fluorescent in situ hybridization (double probe FISH) technique revealed that DPAOs comprised 20% of the total bacterial population. Based on clone libraries construction and nirS gene sequencing analysis, a pronounced shift in denitrifying bacteria diversity was identified during activated sludge acclimatization. Moreover, nirS gene sequences distinct from those detected in any known bacterial strain or environmental clone were identified. This is the first report studying the microbial properties of activated sludge in a DEPHANOX-type system using molecular techniques.


Assuntos
Bactérias/enzimologia , Desnitrificação , Nitrito Redutases/genética , Polifosfatos/metabolismo , Esgotos/microbiologia , Bactérias/genética , Biomassa , Reatores Biológicos/microbiologia , DNA Bacteriano/genética , Genes Bacterianos , Fósforo/metabolismo , Polimorfismo de Fragmento de Restrição , Análise de Sequência de DNA , Eliminação de Resíduos Líquidos/métodos
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