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Catalytic wet air oxidation of olive mill wastewater

Gomes, Helder; Figueiredo, José; Faria, Joaquim
Fonte: EAAOP Publicador: EAAOP
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
48.01708%
The objective of this work was to study the suitability of catalytic wet air oxidation (CWAO) for the treatment of olive mill wastewater (OMW). Accordingly, experiments were performed in a high pressure reactor at 100ºC and 200ºC under an oxygen partial pressure of 6.9 bar, using carbon supported platinum (1wt.% Pt) and iridium (5 wt.% Ir) catalysts prepared by incipient wetness impregnation. Both catalytic systems showed a very high activity in the total organic carbon (TOC) removal of the effluent, an increase in TOC removal relatively to non-CWAO being observed. At 200ºC, complete TOC and colour removal was obtained with the Pt/C catalyst after 8 h of reaction. At 100ºC, the results indicate that a certain fraction of compounds in the effluent (low molecular weight recalcitrant carboxylic acids)could not be removed even after prolonged reaction time. A kinetic model was developed taking into account catalytic and noncatalytic reaction, formation of refractory compounds and catalyst deactivation. A very good agreement between the model results and the CWAO experimental data at 200ºC was found. The results obtained in this work indicate that Pt/C is a promising catalyst for the CWAO of OMW.

Catalytic ozonation of phenolic acids over a Mn-Ce-O catalyst

Martins, Rui C.; Quinta-Ferreira, Rosa M.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
47.91389%
Catalytic ozonation of a simulated phenolic wastewater composed by six acids: syringic, vanillic, 3,4,5-trimethoxybenzoic, veratric, protocatechuic and 4-hydroxybenzoic normally present in olive mill wastewaters was studied over a Mn-Ce-O laboratorial catalyst under different operating conditions. A high improvement in total organic carbon (TOC) degradation was observed even when low catalyst concentrations were used when compared with single ozonation. The influence of the medium pH in the performance of both single and catalytic ozonation was assessed in a wide range of pH values. An inhibitory effect in TOC removal was observed in the catalytic process performance at high pH values. The use of radical scavengers proved that this catalytic system does not follow a free radical pathway. No differences were observed between fresh and used catalyst structure and morphology by SEM and XRD. Nevertheless, a decrease on BET surface area was detected. Leaching of Mn as well as carbon adsorption due to organic intermediates deposition at the catalyst surface was analyzed for the recovered catalyst at the end of the experiments. The role of the catalyst in the catalytic ozonation pathway was discussed being concluded that the main mechanism should be developed through surface reactions involving both pollutants and ozone adsorption. A series of feed-batch trials was performed to test Mn-Ce-O activity along the time. A slight decrease on TOC removal was observed from the first to the second use...

Influence of carbon sources and C/N ratio on EPS production in anaerobic sequencing batch biofilm reactors for wastewater treatment

MIQUELETO, A. P.; DOLOSIC, C. C.; POZZI, E.; FORESTI, E.; ZAIAT, M.
Fonte: ELSEVIER SCI LTD Publicador: ELSEVIER SCI LTD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
47.686133%
The objective of this work was to evaluate the influence of different carbon sources and the carbon/nitrogen ratio (C/N) on the production and main composition of insoluble extracellular polymers (EPS) produced in an anaerobic sequencing batch biofilm reactor (ASBBR) with immobilized biomass in polyurethane foam. The yield of EPS was 23.6 mg/g carbon, 13.3 mg/g carbon, 9.0 mg/g carbon and 1.4 mg/g carbon when the reactor was fed with glucose, soybean oil. fat acids, and meat extract, respectively. The yield of EPS decreased from 23.6 to 2.6 mg/g carbon as the C/N ratio was decreased from 13.6 to 3.4 gC/gN, using glucose as carbon source. EPS production was not observed under strict anaerobic conditions. The results suggest that the carbon source, microaerophilic conditions and high C/N ratio favor EPS production in the ASBBR used for wastewater treatment. Cellulose was the main exopolysaccharide observed in all experimental conditions. (C) 2009 Elsevier Ltd. All rights reserved.; FAPESP - Fundacao de Amparo A Pesquisa do Estado de Sao Paulo, Brasil; CNPq - Conselho Nacional de Desenvolvimento Cientifico e Tecnologico, Brazil

Anaerobic sequencing batch biofilm reactor applied to automobile industry wastewater treatment: Volumetric loading rate and feed strategy effects

OLIVEIRA, Ricardo Polisaitis; GHILARDI, Jose Antonio; RATUSZNEI, Suzana Maria; RODRIGUES, Jose Alberto Domingues; ZAIAT, Marcelo; FORESTI, Eugenio
Fonte: ELSEVIER SCIENCE SA Publicador: ELSEVIER SCIENCE SA
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
58.09961%
This paper presents a technological viability study of wastewater treatment in an automobile industry by an anaerobic sequencing batch biofilm reactor containing immobilized biomass (AnSBBR) with a draft tube. The reactor was operated in 8-h cycles, with agitation of 400 rpm, at 30 degrees C and treating 2.0 L wastewater per cycle. Initially the efficiency and stability of the reactor were studied when supplied with nutrients and alkalinity. Removal efficiency of 88% was obtained at volumetric loading rate (VLR) of 3.09 mg COD/L day. When VLR was increased to 6.19 mg COD/L day the system presented stable operation with reduction in efficiency of 71%. In a second stage the AnSBBR was operated treating wastewater in natura, i.e., without nutrients supplementation, only with alkalinity, thereby changing feed strategy. The first strategy consisted in feeding 2.0 L batch wise (10 min), the second in feeding 1.0 L of influent batch wise (10 min) and an additional 1.0 L fed-batch wise (4 h), both dewatering 2.0 L of the effluent in 10 min. The third one maintained 1.0 L of treated effluent in the reactor, without discharging, and 1.0 L of influent was fed fed-batch wise (4 h) with dewatering 1.0 L of the effluent in 10 min. For all implemented strategies (VLR of 1.40...

Aplicação da eletrodiálise no tratamento da drenagem ácida de minas visando a recuperação de ácido sulfúrico.; Electrodialysis application of acid mine drainage treatment aiming sulfuric acid recovery.

Buzzi, Daniella Cardoso
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 25/10/2012 PT
Relevância na Pesquisa
57.76866%
O principal impacto causado pela atividade de mineração de carvão é a poluição hídrica proveniente da drenagem ácida de minas (DAM), que pode ter efeitos toxicológicos nos ecossistemas aquáticos, como mortalidade, disfunções no crescimento, menores taxas de reprodução, deformidades e lesões. A DAM é formada através da oxidação de minerais de sulfeto, principalmente pirita (FeS2) e caracteriza-se por uma solução de pH ácido e metais dissolvidos (Fe, Al e Mn). Novas metodologias para o tratamento de efluentes contaminados com metais estão sendo estudadas e a eletrodiálise (ED) surge como uma destas tecnologias que tem se mostrado eficaz para a recuperação de água e concentração de eletrólitos. É considerada uma tecnologia atrativa aos mais diversos segmentos, uma vez que apresenta muitas vantagens sobre os processos tradicionais, tais como: não exige mudanças de fases; funciona de forma contínua; não necessita da adição de reagentes e não gera resíduos poluentes ao ambiente. A ED é uma técnica de separação por membranas, no qual espécies iônicas em solução são transportadas através de membranas de troca-iônica por influência da aplicação de um campo elétrico que permite a separação de ânions e cátions metálicos com a vantagem de remover os metais contaminantes e simultaneamente recuperar água e outros compostos de interesse industrial...

Produção de hidrogênio em reator anaeróbio de leito fluidificado a partir de água residuária de soro de queijo em condição termófila; Hydrogen production in anaerobic fluidized bed reactor from cheese whey wastewater under thermophilic condiction

Ottaviano, Livia Maria
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 15/07/2014 PT
Relevância na Pesquisa
47.73345%
O hidrogênio é estudado como alternativa ao uso de combustíveis fósseis para geração de energia, uma vez que é um combustível renovável. Entre os processos de produção de hidrogênio destaca-se o processo fermentativo que possibilita unir tratamento de efluente e geração de energia. Uma das alternativas para esta produção é a utilização do reator anaeróbio de leito fluidificado (RALF). Dentre os resíduos industriais que podem ser utilizados para a produção de hidrogênio está o soro de queijo que, se descartado incorretamente, pode causar danos ao meio ambiente. Neste sentido, o presente estudo teve como principal objetivo avaliar a capacidade de produção contínua de hidrogênio, sob condições termófilas (55°C), a partir de diferentes concentrações de soro de queijo e tempos de detenção hidráulica (TDH) em RALF. Foram utilizados dois reatores, denominados R1 e R2 , no qual R1 manteve-se com concentração fixa de 5 gDQO.L-1, com variações de TDH de 8, 6, 4, 2, 1 e 0,5 hora e em R2 o TDH manteve-se fixo em 6 horas e variações de concentrações de 3, 5, 7 e 10 gDQO.L-1. Foi observado em R1 o comportamento de elevação de produção volumétrica de H2 (PVH) a partir da diminuição do TDH. A máxima PVH obtida foi de 2...

Anaerobic treatment of wastewater from coffee pulping in upflow anaerobic sludge blanket (UASB) in two stages

Bruno, M.; Oliveira, R. A. de
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Conferência ou Objeto de Conferência Formato: 191-198
ENG
Relevância na Pesquisa
48.484927%
In this work, the efficiency of two-stage upflow anaerobic sludge blanket (UASB) reactors was evaluated in bench scale, for treating a liquid effluent from coffee pulping. Hydraulic detention times (HDT) were 4.0; 5.2 and 6.2 days, resulting in organic loading rates (OLR) of 5.8; 3.6 and 3.0g total COD per (L-d) in the first reactor (Rl) and HDT of 2.0; 2.6 and 3.1 days with OLR of 5.8; 0.5 and 0.4 g total COD per (L-d) in the second reactor (R2). The medium values of total COD affluent varied from 15.440 to 23.040 mg O 2/L, and in the effluent to the reactors 1 and 2 were from l.lOO to 11.500 mg 0 2/L and 420 to 9.000 mg O 2/L, respectively. The medium values of removal efficiencies of total COD and TSS varied from 66 to 98% and 93 to 97%, respectively, in the system of treatment with the UASB reactors, in two stages. The content of methane in the biogas varied from 69 to 89% in the Rl and from 52 to 73% in the R2. The maximum volumetric methane production of 0.483 m 3 CH 4per (m 3 reactor d) was obtained with OLR of 3.6 g total COD per (L reactor d) and HDT of 6.2 days in the Rl. The volatile fatty acids concentration was kept below 100mg/L with HDT of 5.2 and 6.2 days in the Rl and HDT of 2.6 and 3.1 days in the R2.

Endurance of methanogenic archaea in anaerobic bioreactors treating oleate-based wastewater

Salvador, A. F.; Cavaleiro, A. J.; Sousa, D. Z.; Alves, M. M.; Pereira, M. A.
Fonte: Springer; Springer Publicador: Springer; Springer
Tipo: Artigo de Revista Científica
Publicado em //2013 ENG
Relevância na Pesquisa
47.891006%
Methanogenic archaea are reported as very sensitive to lipids and long chain fatty acids (LCFA). Therefore, in conventional anaerobic processes, methane recovery during LCFA-rich wastewater treatment is usually low. By applying a start-up strategy, based on a sequence of step feeding and reaction cycles, an oleate-rich wastewater was efficiently treated at an organic loading rate of 21 kg COD m(-3) day(-1) (50 % as oleate), showing a methane recovery of 72 %. In the present work, the archaeal community developed in that reactor is investigated using a 16S rRNA gene approach. This is the first time that methanogens present in a bioreactor converting efficiently high loads of LCFA to methane are monitored. Denaturing gradient gel electrophoresis profiling showed that major changes on the archaeal community took place during the bioreactor start-up, where phases of continuous feeding were alternated with batch phases. After the start-up, a stable archaeal community (similarity higher than 84 %) was observed and maintained throughout the continuous operation. This community exhibited high LCFA tolerance and high acetoclastic and hydrogenotrophic activity. Cloning and sequencing results showed that Methanobacterium- and Methanosaeta-like microorganisms prevailed in the system and were able to tolerate and endure during prolonged exposure to high LCFA loads...

The Impact of Microbial Ecology and Chemical Profile on the Enhanced Biological Phosphorus Removal (EBPR) Process: A Case Study of Northern Wastewater Treatment Works, Johannesburg

Kamika, Ilunga; Coetzee, Martie; Mamba, Bhekie Brilliance; Msagati, Titus; Momba, Maggy N. B.
Fonte: MDPI Publicador: MDPI
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
48.143867%
The impact of polyphosphate-accumulating organism (PAO) and glycogen-accumulating organism (GAO) populations as well as of the chemical profile on the performance of Unit-3 (open elutriation tanks) and Unit-5 (covered elutriation tank) of the City of Johannesburg Northern Wastewater Treatment Works was determined. Physicochemical parameters of wastewater samples were measured using standard methods. Bacterial diversity was determined using 16S rRNA gene amplicon pyrosequencing of the variable region V1-3. Results showed soluble COD concentrations from settled sewage for Unit-3 at 192.8 mg COD/L and for Unit-5 at 214.6 mg COD/L, which increased to 301.8 mg COD/L and 411.6 mg COD/L in the overflow from elutriation tanks and decreased to 170.9 mg COD/L and 256.3 mg COD/L at the division boxes, respectively. Both long-chain volatile fatty acids (heptanoic acid, isobutyric acid, 3-methylbutanoic acid, pentanoic acid, 4-methylpentanoic acid, methylheptanoic acid) and short-chain volatile fatty acids (acetic acid, propionic acid, isobutyric acid) were present within concentration ranges of 17.19 mg/L to 54.98 mg/L and 13.64 mg/L to 87.6 mg/L for Unit 3 and 38.61 mg/L to58.85 mg/L and 21.63 mg/L to 92.39 mg/L for Unit 5, respectively. In the secondary settling tanks...

Metagenomic analyses reveal phylogenetic diversity of carboxypeptidase gene sequences in activated sludge of a wastewater treatment plant in Shanghai, China

Jin, Hao; Li, Bailin; Peng, Xu; Chen, Lanming
Fonte: Springer Berlin Heidelberg Publicador: Springer Berlin Heidelberg
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
48.02432%
Activated sludge of wastewater treatment plants carries a diverse microflora. However, up to 80–90 % of microorganisms in activated sludge cannot be cultured by current laboratory techniques, leaving an enzyme reservoir largely unexplored. In this study, we investigated carboxypeptidase diversity in activated sludge of a wastewater treatment plant in Shanghai, China, by a culture-independent metagenomic approach. Three sets of consensus degenerate hybrid oligonucleotide primers (CODEHOPs) targeting conserved domains of public carboxypeptidases have been designed to amplify carboxypeptidase gene sequences in the metagenomic DNA of activated sludge by PCR. The desired amplicons were evaluated by carboxypeptidase sequence clone libraries and phylogenetic analyses. We uncovered a significant diversity of carboxypeptidases present in the activated sludge. Deduced carboxypeptidase amino acid sequences (127–208 amino acids) were classified into three distinct clusters, α, β, and γ. Sequences belonging to clusters α and β shared 58–97 % identity to known carboxypeptidase sequences from diverse species, whereas sequences in the cluster γ were remarkably less related to public carboxypeptidase homologous in the GenBank database...

The Impact of D-amino acids on Formation and Integrity of Biofilm – Effect of Growth Condition and Bacteria Type

Li, Xuening
Fonte: Universidade Rice Publicador: Universidade Rice
ENG
Relevância na Pesquisa
47.65949%
Biofouling is a major issue in applying nanofiltration and reverse osmosis technologies for wastewater treatment. Biofilm formed on the surface of membranes will severely decline the flux and cause energy waste. In this study, a novel biofouling control method that applies D-amino acids to inhibit biofilm formation was investigated. The D-amino acids previously reported to inhibit biofilm formation and disrupt existing biofilm – D-tyrosine and the mixture of D-tyrosine, D-tryptophan, D-leucine and D-methionine were tested. Pseudomonas aeruginosa and Bacillus subtilis were used as model Gram-negative and Gram-positive bacteria, respectively. D-amino acids have little effect and some effect on inhibition of biofilm formation and disruption of exiting biofilm to Pseudomonas aeruginosa, but have good effect to Bacillus subtilis. A commonly used microtiter plate assay for quantitative biofilm measurement was systematically evaluated and optimized for screening biofilm control agents. The effect of D-tyrosine on inhibition of organic fouling and P. aeruginosa biofouling on NF90 membrane surface in bench scale dead end filtration experiment was examined, which shows that D-tyrosine can effectively inhibit organic fouling and P. aeruginosa biofouling on NF90 membrane surface.

Start-up and feeding strategy of an anaerobic sequencing batch reactor for olive mill wastewater treatment

Costa, J. C.; Gonçalves, M. R.; Marques, I. P.; Alves, M. M.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em //2010 ENG
Relevância na Pesquisa
58.235806%
Olive mill wastewater (OMW) is the effluent generated by olive oil industries, mainly produced in the Mediterranean areas. The production of olive oil generates huge amounts of wastewater. Anaerobic wastewater treatment processes appears as a promising technology for the treatment and energetic potential recovery of these high strength wastewaters since a renewable energy source (biogas) is generated. However, due to the high organic contents and presence of lipidic and phenolic compounds the treatment of OMW is sometimes toxic to the anaerobic microorganisms. Aiming at define the best strategy for the anaerobic sequencing batch reactor start-up, two reactors were operated with an hydraulic retention time of 10 days, fed with OMW at 5gCOD/L. In batch assays it was previously observed that when using an adapted microbial consortium to lipids, OMW was more efficiently converted to biogas and the overall methane production was higher. On the other hand an intermittent feeding start-up was proven to promote the degradation of long chain fatty acids to methane. Therefore, two reactors, R1 and R2 were inoculated with a biomass acclimated to oleate (BAO) and a biomass non-acclimated (BNA), respectively. The inoculum type effect on start-up efficiency and the benefits of an intermittent feeding were studied. In both reactors...

Start-up of anaerobic reactors for slaughterhouse wastewater treatment

FIA,RONALDO; PEREIRA,ERLON L.; FIA,FÁTIMA R. L.; EMBOABA,DÉBORA G.; GOMES,EMANUEL M.
Fonte: Associação Brasileira de Engenharia Agrícola Publicador: Associação Brasileira de Engenharia Agrícola
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2015 EN
Relevância na Pesquisa
47.938994%
This study aimed to evaluate the start-up of a horizontal anaerobic fixed bed reactor (HAFBR) followed by an upflow anaerobic sludge blanket (UASB) for the slaughterhouse wastewater treatment. HAFBR was filled with bamboo rings and had 1.2 m in length, 0.10 m in diameter and volume of 7.5 L. The UASB had the volume of 15 L. The HAFBR and UASB operated at organic loading rate and hydraulic retention time average of 8.46 and 3.77 kg m-3 d-1 of COD and 0.53 and 0.98 days, respectively. During 150 days of monitoring system it was found pH 6.8, relatively high values of bicarbonate alkalinity (> 1000 mg L-1) and reduced values of volatile acids (70 to 150 mg L-1), which afforded average removal efficiencies of COD total and total suspended solids of the order of 31 and 23% in HAFBR and 79% and 63% in UASB. It can be concluded that the generation and consumption of bicarbonate alkalinity and total volatile acids, thereby maintaining the pH during the study indicated stable operation of the reactors. The COD removal in the reactors was satisfactory especially when it considers that the assessment was conducted in a period of adaptation of organisms to the effluent and also the high organic load applied during this period.

Biodegradação e bioconversão do d-limoneno por bactérias isoladas de esgoto doméstico; Biodegradation and bioconversion of d-limonene by bacteria isolated from wastewater

Sheila de Oliveira
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 02/07/2013 PT
Relevância na Pesquisa
48.235806%
As indústrias cítricas geram grandes quantidades de efluentes líquidos. Estes efluentes são potencialmente poluidores para descarte em corpos d'água e necessitam de tratamento adequado. A maioria das plantas de tratamento de efluentes cítricos utiliza processos biológicos, devido a custos operacionais mais baixos quando comparado aos processos físico-químicos. Porém, estas plantas têm apresentado problemas de eficiência de remoção da carga orgânica e inibição da atividade biológica, em função das características tóxicas do efluente cítrico, devido à presença residual do d-limoneno, um monoterpeno extraído da casca da laranja. O d-limoneno, quando separado e purificado, tem ampla aplicação industrial, na área cosmética como fragrância e na área alimentícia como agente antimicrobiano e também pode ser bioconvertido em produtos como ácidos e alcoóis perílicos e carvona que podem ser utilizados na terapia do câncer. Os objetivos deste estudo foram selecionar e identificar microrganismos capazes de degradar o d-limoneno em altas concentrações (até 5%), simulando condições similares aos efluentes cítricos e avaliar o comportamento de consórcio destes microrganismos. Também foi avaliada a qualificação dos produtos obtidos da bioconversão do d-limoneno. Os microrganismos foram isolados a partir do lodo ativado de uma estação de tratamento de esgotos. Uma pré-seleção...

Fenton's process applied to wastewaters treatment

Rossi, André Fernandes
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Tese de Doutorado
ENG
Relevância na Pesquisa
48.277188%
Water resources are not infinite. If even nowadays some people do not have proper access to this vital supply, humanity must do much more effort aiming its preservation in consideration with the future of the generations to come. Avoiding all types of pollutants from contaminating water cycles is currently one of the current utmost matters to be faced by government policies. Research on wastewaters treatment have been dealing this regard over many years now, strongly contributing with solutions to the related problems. The most frequently remediation techniques to several kinds of effluents are the biological treatments, where microorganisms consume the organic charge – thus requiring biomass adaptation when there are changes on substrates composition. Drawbacks emerge when non-biodegradable or toxic effluents must be dealt with. This, sometimes, makes it impossible to treat effluents by activated sludge, especially when the effluent is not available all over the year for bacteria to have time to get acclimated. Therefore, accordingly to the kind or content of the residues requiring remediation before discharge, different approaches may be considered instead. Portugal alone produced 80 kilotons of olive oil in 2012. In the same year...

Advanced liquid chromatography-mass spectrometry (LC-MS) methods applied to wastewater removal and the fate of surfactants in the environment

González Blanco, Susana; Petrovic, Mira; Barceló, Damià
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 162 bytes; application/msword
ENG
Relevância na Pesquisa
58.1504%
9 pages, 4 figures, 1 table.-- Printed version published Feb 2007.; This article is an overview of current methodologies for the analysis of different classes of surfactants by advanced liquid chromatography-mass spectrometry (LC-MS) technologies, including LC-tandem MS (LC-MS2), ion trap, quadrupole-time-of-flight (Q-TOF) and matrix-assisted laser desorption/ionization (MALDI)-TOF. It also discusses the application of LC-MS methods in studies of the fate and the behavior of surfactants during wastewater treatment either using conventional activated sludge (CAS), membrane bioreactor (MBR) or advanced oxidation processes (AOPs). Using advanced LC-MS methodologies, it is possible to detect a variety of polar metabolites, such as carboxylic acids and short-chain sulphonic-acid derivatives of surfactants formed during the biodegradation processes in either the wastewater-treatment plants or the environment.; The work described in this article was supported by the EU Project EMCO (INCO-CT-2004-509188) and by the Spanish Ministerio de Educación y Ciencia, Project EVITA (CTM2004-06255-CO3-01). S. González acknowledges a grant from the Spanish MCyT (PPQ2001-1805-CO3-01).; Peer reviewed

Comparative study on the treatment of a high-strenght p-nitrophenol wastewater

Martín Hernández, Mariángel
Fonte: [Barcelona] : Universitat Autònoma de Barcelona, Publicador: [Barcelona] : Universitat Autònoma de Barcelona,
Tipo: Tesis i dissertacions electròniques; info:eu-repo/semantics/doctoralThesis; info:eu-repo/semantics/publishedVersion Formato: application/pdf
Publicado em //2014 ENG
Relevância na Pesquisa
48.228438%
El p-Nitrophenol (PNP) es un compuesto que tiene numerosas aplicaciones en la industria química; es empleado como materia prima en la industria farmacéutica, de pesticidas y en la manufactura de cuero. Sin embargo, es un compuesto dañino para los humanos, los animales y el medio ambiente. Exposiciones repetidas al PNP pueden causar daños en los glóbulos rojos, en el sistema nervioso central y efectos mutagénicos. La selección del tratamiento adecuado para la remediación de aguas residuales industriales que contengan compuestos recalcitrantes, como el PNP, depende de la naturaleza del compuesto, su concentración y su carga. Por consiguiente, en esta tesis se realizó un estudio comparativo de diferentes tecnologías para el tratamiento de aguas residuales que contienen altas concentraciones de PNP tomando en cuenta las características de dichas aguas. Primeramente, se estudió el tratamiento biológico de aguas contaminadas con PNP en un reactor aeróbico secuencial por lotes (SBR). La puesta en marcha del reactor fue realizada utilizando como inóculo biomasa no aclimatada, proveniente de una estación depuradora de aguas urbanas, y agua sintética que contenía una mezcla de PNP y glucosa – sacarosa como fuentes de carbono. Se aplicó una estrategia operacional específica con el objetivo de desarrollar lodos activos del tipo estrategas de la K. Durante todo el período de operación se obtuvo un 100% de eliminación del PNP. Se realizaron estudios respirométricos para caracterizar cinéticamente los degradadores de PNP. Los valores cinéticos obtenidos confirmaron que la biomasa obtenida es del tipo estrategas de la K...

Converting wastewater treatment facilities into biorefineries: biodiesel from wastewater microorganisms

Kiracofe, Nathan
Fonte: University of Delaware Publicador: University of Delaware
Tipo: Tese de Doutorado
Relevância na Pesquisa
48.35535%
Cha, Daniel K.; In a world with growing energy demands, increasing dependence on fossil fuels has become the norm, but given the finite supply of these fuels, this is no longer a sustainable approach. Biodiesel is one alternative renewable fuel source with great promise. Unlike other forms of renewable energy, biodiesel is directly usable in existing forms of technology, such as the diesel engine, and does not require significant retrofitting. Biodiesel is composed of fatty acid esters, like fatty acid methyl ester (FAME), which are made via the transesterification reaction, wherein fatty acids are esterified with alcohol in the presence of a catalyst. Traditionally biodiesel has been produced from vegetable oils, however, recently many alternative feedstocks, such as used cooking oil, have been gaining significant attention. One interesting alternative feedstock with very limited research is wastewater sludge, a major by product of the wastewater treatment process. Rich in fatty acids that are ripe for transesterification, wastewater sludge offers significant potential as a biodiesel feedstock.; University of Delaware, Department of Civil and Environmental Engineering; M.C.E.

Dispersion model to describe the carbon removal from wastewater in a fixed bed up flow pilot bioreactor with a hexagonal feldspar packing

Martínez-Delgadillo,S. A.; Rodríguez-Cruz,M.; Rodríguez-Rosales,M. G.
Fonte: UAM, Unidad Iztapalapa, División de Ciencias Básicas e Ingeniería Publicador: UAM, Unidad Iztapalapa, División de Ciencias Básicas e Ingeniería
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2008 EN
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In this work the modeling of carbon removal from wastewater in a fixed bed up flow pilot bioreactor with a hexagonal feldspar packing was carried out. The performance of a hexagonal feldspar packing was evaluated in an aerated biological pilot reactor. The feldspar packing was obtained by direct extrusion followed by sintering at 1100°C, during 4 hours, conditions at which the highest porosity and specific surface area were obtained. In addition to its easy preparation and low cost, the packing presented chemical resistance to different acids. The biological fixed bed up flow reactor with a total volume of 30.7 L was randomly packed with the hexagonal pieces of feldspar. Dispersion test were performed with a tracer (KCl), to estimate the dispersion number (Nd) in the reactor, with and without aeration. It was found that the dispersion increased due to the aeration and exerts a strong influence on reactor performance. A plug flow reactor model with axial dispersion and Monod kinetic was used to describe the carbon removal (COD) in the reactor at different hydraulic loading rates. The wastewater used during the tests was sampled at the exit of the primary settler of a Mexican wastewater treatment plant, being a mixture of industrial and urban effluents...

Effect of bicarbonate alkalinity on gravimetric solids analysis in anaerobic wastewater treatment

Soares Damasceno,Leonardo H; Rodrigues,José A. D; Ratusznei,Suzana M; Mattos Moraes,Elizabeth; Zaiat,Marcelo; Foresti,Eugenio
Fonte: ASOCIACIÓN INTERCIENCIA Publicador: ASOCIACIÓN INTERCIENCIA
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2007 EN
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Bicarbonate alkalinity plays an important role in the stability of biological reactors used in wastewater treatment, primarily in anaerobic systems. As some wastewaters tend to acidify readily, addition of an external alkali source may be necessary to maintain process stability. An assessment was made of the effect of sodium bicarbonate addition on the determination of solids concentration. The methodology consisted in accompanying a series of solids concentrations (total solids, TS; total volatile solids, TVS; and total fixed solids, TFS) in samples containing cheese whey and volatile acids used to simulate anaerobic reactor effluents. TS, TVS and TFS showed to be strongly affected by NaHCO3 addition, mainly due to an increase in TFS. This effect could be quantified by relating the experimental values to the theoretical ones from the stoichiometric equations for NaHCO3 decomposition and other compounds (sodium acetate and sodium propionate) formation with temperature increase. In this way, as one of the main parameters of assessing liquid effluent treatment systems is the reduction in solids present in the medium, the concentration of solids can be quantified more adequately by determining fixed solids from the inorganic salts present. This methodology showed to be adequate in cases where a significant amount of alkali is added.