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Otimização de processos físico-químicos na remoção de fósforo de esgotos sanitários por processos de precipitação química com cloreto férrico; Physical-chemical process optimization for phosphorus removal from domestic wastewater by chemical precipitation with ferric chloride

Marguti, André Luiz; Filho, Sidney Seckler Ferreira; Piveli, Roque Passos
Fonte: ABES Publicador: ABES
Tipo: Artigo de Revista Científica
POR
Relevância na Pesquisa
36.46%
Tendo em vista a potencialidade do emprego de processos de coagulação química no tratamento de esgotos, este trabalho teve por objetivo estudar a remoção de fósforo em efluentes de sistemas anaeróbios e aeróbios de tratamento de esgotos. Observou-se que foi possível atingir valores de remoção de fósforo da ordem de 90%, sendo que as dosagens de coagulante se situaram em torno de 60 a 100 mg FeCl3/L. Concomitantemente com a remoção de fósforo, foi também observada uma remoção de carbono orgânico dissolvido (COD) para os efluentes investigados, sendo que as dosagens de coagulante que permitiram a otimização da remoção de fósforo também possibilitaram a otimização da remoção de COD. Justifica-se a remoção de fósforo na forma orgânica e de polifosfatos pelo fato destes estarem associados ao COD removido.; Since chemical coagulation processes are very promising for wastewater treatment, this work looked into phosphorus removal from aerobic and anaerobic systems treating domestic wastewater. It was possible to reach phosphorus removal efficiencies in the order of 90 % for coagulant dosages in the range 60 to 100 mg of ferric chloride per liter. Dissolved organic carbon (DOC) removal in parallel with phosphorus removal was observed for the previously mentioned treatment system effluents. The coagulant dosages for optimized phosphorus removal also led to optimum DOC removal. The removal of organic phosphorus fractions as polyphosphates was justified due its association with the DOC removal by chemical precipitation.; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

LPS Removal from an E. Coli Fermentation Broth Using Aqueous Two-Phase Micellar System

LOPES, Andre M.; MAGALHAES, Perola O.; MAZZOLA, Priscila G.; RANGEL-YAGUI, Carlota O.; CARVALHO, Joao C. M. de; PENNA, Thereza C. V.; PESSOA JR., Adalberto
Fonte: JOHN WILEY & SONS LTD Publicador: JOHN WILEY & SONS LTD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.42%
In biotechnology, endotoxin (LPS) removal from recombinant proteins is a critical and challenging step in the preparation of injectable therapeutics, as endotoxin is a natural component of bacterial expression systems widely used to manufacture therapeutic proteins. The viability of large-scale industrial production of recombinant biomolecules of pharmaceutical interest significantly depends on the separation and purification techniques used. The aim of this work was to evaluate the use of aqueous two-phase micellar system (ATPMS) for endotoxin removal from preparations containing recombinant proteins of pharmaceutical interest, such as green fluorescent protein (GFPuv). Partition assays were carried out initially using pure LPS, and afterwards in the presence of E. coli cell lysate. The ATPMS technology proved to be effective in GFPuv recovery, preferentially into the micelle-poor phase (K(GFPuv) < 1.00), and LPS removal into the micelle-rich phase (%REM(LPS) > 98.00%). Therefore, this system can be exploited as the first step for purification in biotechnology processes for removal of higher LPS concentrations. (C) 2010 American Institute of Chemical Engineers Biotechnol. Prog., 26: 1644-1653, 2010; Capes - Brazil; National Council for Scientific and Technological Development (CNPq - Brazil); State of Sao Paulo Research Support Foundation (Fapesp - Brazil)

Influence of Er:YAG Laser Frequency on Dentin Caries Removal Capacity

RAUCCI-NETO, Walter; CHINELATTI, Michelle Alexandra; ITO, Izabel Yoko; PECORA, Jesus Djalma; PALMA-DIBB, Regina Guenka
Fonte: WILEY-BLACKWELL Publicador: WILEY-BLACKWELL
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.45%
The purposes of this study were to evaluate in vitro the influence of different frequencies of Er:YAG laser on the human dentin caries removal capacity. Thirty fragments obtained from third molars were randomly assigned into three groups (n = 10) according to the laser frequency used: 4, 6, and 10 Hz. The caries lesion (+/-1 mm deep) was induced before the irradiation by S. mutans cultures for 6 weeks. The specimens of all groups were irradiated with 200 mJ of energy in noncontact and focused mode under constant refrigeration (water flow: 2.5 mL/min). Quantitative analysis of the caries removal was performed by DIAGNOdent (TM) and the Axion Vision (TM) software. Qualitative analysis was performed by Scanning electron microscope (SEM) and light microscope (LM). Data were analyzed by ANOVA and Fishers` tests. The DIAGNOdent (TM) revealed that the caries removal was similar with 4 and 6 Hz and was superior with 10 Hz (P < 0.05). The analysis with Axion Vision (TM) software revealed that the caries removal was similar with 6 and 10 Hz and the 4 Hz group promoted the lowest caries removal. Through SEM morphologic analysis, some specimens irradiated with 4 Hz presented, under the demineralized dentin, a disorganized collagenous matrix. The LM images revealed that all frequencies used promoted irregular caries removal...

"Avaliação da dentina remanescente após remoção de cárie com instrumento cortante rotatório e métodos químico-mecânicos, utilizando análise de microdureza, fluorescência laser e MEV" ; Evaluation of residual dentine after conventional and chemomechanical caries removal using microhardness test, laser fluorescence and SEM.

Corrêa, Fernanda Nahás Pires
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 13/01/2006 PT
Relevância na Pesquisa
36.48%
Este trabalho in vitro teve objetivo de avaliar a superfície dentinária remanescente após remoção de tecido dentinário cariado, com instrumento cortante rotatório em baixa rotação e dois métodos químico-mecânicos (Papacárie® e Carisolv®) através da fluorescência laser (DIAGNOdent), microdureza e microscopia eletrônica de varredura. Na primeira fase do estudo, trinta incisivos decíduos com lesão de cárie em uma das faces proximais provenientes do Banco de Dentes Humanos da FOUSP foram avaliados antes e após a remoção do tecido cariado, pela fluorescência laser, sendo posteriormente preparados avaliação da microdureza . O teste de microdureza foi realizado em diferentes distâncias abaixo da dentina tratada após remoção do tecido cariado (50, 100, 150, 200, 300, 400 e 500µm) e do lado hígido (100, 150, 200, 300, 400, 500, 1000 e 1500 µm). Posteriormente, mais 30 dentes decíduos cariados foram divididos em três grupos de acordo com os diferentes tipos de tratamento para análise em MEV, sendo 15 dentes para análise do substrato e 15 dentes para observação de réplicas. Para obtenção destas, os dentes foram restaurados com o adesivo Single Bond (3M) e resina Filtek Z100 (3M) para avaliação de tags (15). Concluiu-se que houve diferença estatisticamente significante nos valores de fluorescência laser da dentina cariada e da dentina após a remoção do tecido cariado...

Desempenho de um reator vertical de fluxo contínuo e leito estruturado com recirculação do efluente, submetido à aeração intermitente, na remoção de carbono e nitrogênio de um efluente sintético; Performance of vertical reactor of continuous flow and bed structured with recirculation, submitted to intermittent aeration for the removal of carbon and nitrogen from a synthetic effluent

Moura, Rafael Brito de
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 18/03/2011 PT
Relevância na Pesquisa
36.45%
Essa pesquisa teve como objetivo principal avaliar o desempenho de um reator de leito estruturado e fluxo contínuo, sob diferentes condições operacionais como aeração intermitente e recirculação do efluente, na remoção biológica de carbono e nitrogênio de uma água residuária sintética. Foi utilizado um reator vertical, construído em acrílico, com um volume total de 11,6 L e um volume útil de 6,1 L. O meio suporte utilizado para fixação dos microrganismos foi espuma de poliuretano na forma de cilindros dispostos verticalmente suportados por hastes, presos nas extremidades. A razão de recirculação utilizada durante todo o experimento foi igual a 5. Os períodos adotados de aeração e não aeração foram de 2 horas e 1 hora, respectivamente. Estabelecidos a vazão de recirculação e os períodos de aeração e não aeração, estudou-se o efeito da variação do TDH na eficiência de remoção de 'N'-total e DQO. Como resultado, observou-se que a melhor condição operacional foi com TDH de 12 horas, que apresentou eficiência de remoção de 'N'-total de 82% e remoção de DQO de 89%. O sistema mostrou-se estável ao ser operado nessas condições, apresentando pouca variação nos resultados. Por outro lado...

Avaliação da sensibilidade dentária durante a remoção seletiva de lesões de cárie em dentes decíduos utilizando laser de Er:YAG; Evaluation of tooth sensitivity during the selective carious lesions removal in primary teeth using Er:YAG laser.

Polizeli, Silvana Aparecida Fernandes
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 11/06/2013 PT
Relevância na Pesquisa
36.45%
A realização de preparos cavitários que removam menor quantidade de substrato dentário sadio, oferecendo maior conforto e menor sensibilidade durante o tratamento odontológico em crianças, associado ao emprego de materiais restauradores estéticos adesivos são procedimentos comumente empregados na odontologia minimamente invasiva. O presente estudo tem por objetivo avaliar a sensibilidade dentária durante a remoção seletiva das lesões de cárie e preparo cavitário em dentes decíduos e o método de remoção de tecido cariado preferido pelas crianças. Foram selecionadas 20 crianças entre 7 e 10 anos, apresentando pelo menos duas lesões de cárie ativas, com cavitação atingindo dentina localizadas na superfície oclusal de molares decíduos homólogos. Os dentes de cada criança foram distribuídos aleatoriamente em dois grupos: (I) Laser de Er:YAG (250mJ / 4 Hz), para remoção do esmalte cavo superficial e remoção seletiva da lesão de cárie associado a curetas e (II) Método Convencional (turbina de alta rotação para remoção do esmalte cavo-superficial e turbina de baixa rotação para a remoção seletiva do tecido cariado associado a curetas). A sensibilidade dentária foi analisada durante a remoção seletiva de lesões de cárie e preparo cavitário...

Remoção de matéria orgânica e nitrogênio de esgoto sanitário em reator de leito estruturado submetido à aeração intermitente e recirculação do efluente; Simultaneous carbon and nitrogen removal from sewage in a structured bed biofilm reactor subjected to intermittent aeration and effluent recirculation

Moura, Rafael Brito de
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 10/10/2014 PT
Relevância na Pesquisa
36.48%
O objetivo deste trabalho foi o de avaliar o desempenho de um reator de leito estruturado submetido à aeração intermitente (LEAI) na remoção de matéria orgânica e nitrogênio de esgoto sanitário. O reator apresentava um volume total de 11,6 L, com uma porosidade do leito de 52%. O leito estruturado era composto de 13 estruturas cilíndricas (diâmetro igual a 3 cm) de espuma de poliuretano, dispostas verticalmente no interior do reator. A alimentação do reator era feita continuamente com esgoto sanitário, sendo este proveniente de um interceptor de esgoto que passava próximo ao laboratório onde o sistema foi montado. O reator era provido de sistema de recirculação interna, com razão de recirculação igual a 3, valor este adotado após a realização de ensaios hidrodinâmicos. Foram testadas 4 condições operacionais diferentes, variando-se o tempo de detenção hidráulica (TDH) e os períodos de aeração e não aeração. Para cada condição operacional, foram feitos os seguintes estudos: avaliação da eficiência de remoção de matéria orgânica e nitrogênio, determinação da atividade nitrificante e desnitrificante, determinação do número mais provável (NMP) da comunidade nitrificante e desnitrificante...

Shoot density, leaf removal and cluster thinning effects on microclimate, yield and fruit composition of the portuguese vine variety Touriga Nacional

Castro, Rogério; Cruz, Amândio; Rodrigues, Carlos A.; Botelho, Manuel; Rodrigues, Carlos; Rodrigues, Ana; Gomes, Casimiro
Fonte: Universidade Técnica de Lisboa Publicador: Universidade Técnica de Lisboa
Tipo: Conferência ou Objeto de Conferência
Publicado em //2007 ENG
Relevância na Pesquisa
36.45%
The evaluation of shoot density, basal leaf removal, and cluster thinning effects on canopy microclimate characteristics and their influence on yield and fruit composition, was carried out during 2 years (2005 to 2006) on one of the most important and noble Portuguese vine varieties – ‘Touriga Nacional’. The experimental field belongs to the private company Dão Sul, Soc. Vitivinícola, SA, located at Dão region, in centre of Portugal. The vineyard was grafted in 1991 onto 1103 P rootstock. The training system is bilateral Royat with vertical shoot positioning. Three different shoot densities were assayed (at G stage of Baggiolini scale): 23 shoots.m-1 row (D23), 17 shoots.m-1 row (D17) and 11 shoots.m-1 row (D11). At veraison, two other factors were introduced: leaf removal at fruit zone – LR1 (no leaf removal - LR0) and cluster thinning (30%) – CT1 (no cluster thinning – CT0). During the growing season several parameters were measured: leaf area, leaf water potential, leaf gas-exchanges, leaf layer number (LLN), canopy size, intercepted photosynthetically active radiation (PAR), fruit composition, yield and vigour. The reduction of shoot density and clusters thinning slightly improved the canopy microclimate...

Combined biologic removal of sulphate for tanning industrial wastewaters

Di Berardino, Santino
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em 08/08/2009 ENG
Relevância na Pesquisa
36.46%
A biologic pretreatment technology of mixed tanneries wastewater, suitable for sulphate-rich industrial wastewaters, has been studied, in order to eliminate chemical precipitation and improve removal efficiency of the relevant pollutants. It couples an anaerobic reactor with an aerobic sulphide oxidant (ASO) step, where H2S2 is partially oxidized to elemental sulphur, and includes a recirculation system. The proposed solution provided Methanogenic Archae (MA) and Sulphate Reducing Bacteria (SRB) coexistence and controlled inhibition by partial oxidation of hydrogen sulphide.. The removal effiency of the anaerobic reactor was quite dependent on temperature and hydaulic retention time (HRT). COD removal varied between 32-68 % and sulphate removal (20-60%), referred to the mixture of the industrial effluent diluted with 50% of recirculation, at an Organic Load (OL) ranging from 0.5 to 1.5 kg CODM³ d⁻¹ and HRT from 1 to 5 days. The entire biologic pretreatment (AHF+ASO) resulted much more efficient and COD removal increased to 64-82% being less dependent on temperature variations. This process removed also a significant part (85%) of Chromium (Cr⁺³), by sorption into the biologic sludge. This two step biologic pretreatment, ensured better removal of relevant parameters than conventional chemical precipitation...

Influence of bed media characteristics on ammonia and nitrate removal in shallow horizontal subsurface flow constructed wetlands

Albuquerque, A.; Oliveira, J.; Semitela, S.; Amaral, L.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /12/2009 ENG
Relevância na Pesquisa
36.45%
Two bed media were tested (gravel and Filtralite) in shallow horizontal subsurface flow (HSSF) constructed wetlands in order to evaluate the removal of ammonia and nitrate for different types of wastewater (acetate-based and domestic wastewater) and different COD/N ratios. The use of Filtralite allowed both higher mass removal rates (1.1 g NH4–N m−2 d−1 and 3 g NO3–N m−2 d−1) and removal efficiencies (>62% for ammonia, 90–100% for nitrate), in less than 2 weeks, when compared to the ones observed with gravel. The COD/N ratio seems to have no significant influence on nitrate removal and the removal of both ammonia and nitrate seems to have involved not only the conventional pathways of nitrification–denitrification. The nitrogen loading rate of both ammonia (0.8–2.4 g NH4–N m−2 d−1) and nitrate (0.6–3.2 g NO3–N m−2 d−1) seem to have influenced the respective removal rates.

Impact of aeration conditions on the removal of low concentrations of nitrogen in a tertiary partially aerated biological filter

Albuquerque, A.; Makinia, J.; Pagilla, K.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2012 ENG
Relevância na Pesquisa
36.45%
A submerged biological aerated filter (BAF) partially aerated was used to study the removal of low concentrations of ammonia nitrogen (0.3 g N/m3 to 30.5 g N/m3) typically found in nutrient enriched river and lake waters, and treated effluents. Four series of experiments were performed with a synthetic wastewater at ammonia loading rates between 6 g N/m3 d and 903 g N/m3 d and C/N ratios from 2 to 20. The results showed that ammonia removal rates reached higher values (172 g N/m3 d to 564 g N/m3 d) for C/N = 2 and lower values (13.6 g N/m3 d to 34.6 g N/m3 d) for C/N = 20. Between 50% and 70% of the ammonia was removed in the upper section of the BAF, where the dissolved oxygen (DO) concentration was over 2.1 g O2/m3 and the biofilm depth ranged from 0.4 to 0.6 mm. At the bottom section of the reactor, simultaneous removal of ammonia and nitrate was observed at the DO concentrations in the range 0.4 g O2/m3 to 0.8 g O2/m3. There was no removal of ammonia nitrogen for loads below 15 g N/m3.d. The results indicate that the removal of nitrogen in partially aerated BAF may not only be explained by the conventional mechanisms of nitrification/denitrification.

Plant functional groups: scientometric analysis focused on removal experimentsPlant functional groups: scientometric analysis focused on removal experiments

Morais,Joicy Martins; Cianciaruso,Marcus Vinicius
Fonte: Sociedade Botânica do Brasil Publicador: Sociedade Botânica do Brasil
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2014 EN
Relevância na Pesquisa
36.45%
Understanding what determines species co-occurrence and its consequences for ecosystem functioning is central to the study of plant ecology. The ecological similarity of species can explain co-occurrence patterns, species interactions, and how species affect ecosystem processes. A useful approach to answer these questions is to group similar species in functional groups and then perform removal experiments. Here, we conducted a scientometric review of articles about plant functional diversity and plant functional group removal. We identified publication patterns and impact; environmental and geographic gaps; ecological effects being tested; which groups are removed; and what the removal methods are. We analyzed articles published between 1991 and 2012 in journals indexed for the Thomson ISI Web of Science database. Although the number of articles and citations of experimental articles increased during that period, the corresponding increase for functional diversity articles was 12 times greater. This might be because field and cafeteria experiments are harder to conduct. Most studies were performed in temperate regions, where taxonomic knowledge and scientific investment is greater. Studies on herbaceous vegetation predominate, probably because short-lived species are more easily removed and manipulated than are trees. The main reason for the removal experiments was to test hypotheses related to competition...

Insight into removal kinetic and mechanisms of anionic dye by calcined clay materials and lime

Vimonses, V.; Jin, B.; Chow, C.
Fonte: Elsevier Science BV Publicador: Elsevier Science BV
Tipo: Artigo de Revista Científica
Publicado em //2010 EN
Relevância na Pesquisa
36.45%
Our recent work reported that a mixed adsorbent with natural clay materials and lime demonstrated an enhanced capacity and efficiency to remove anionic Congo Red dye from wastewater. This study aims to investigate the removal kinetic and mechanisms of the mixed materials involved in the decolourisation of the dye to maximise their prospective applications for industrial wastewater treatment. The experimental results showed that dye removal was governed by combined physiochemical reactions of adsorption, ion-exchange, and precipitation. Ca-dye precipitation contributed over 70% total dye removal, followed by adsorption and ion-exchange. The dye removal kinetic followed the pseudo-second-order expression and was well described by the Freundlich isotherm model. This study indicated pH was a key parameter to govern the removal mechanisms, i.e. adsorption/coagulation at acidic pH and precipitation at basic condition. Yet, the overall removal efficiency was found to be independent to the operation conditions, resulting in more than 94% dye removal. This work revealed that the mixed clays and lime can be applied as alternative low-cost adsorbents for industrial wastewater treatment.; http://www.elsevier.com/wps/find/journaldescription.cws_home/502691/description#description; Vipasiri Vimonses...

The importance of rim removal in deep lateral orbital wall decompression

Kakizaki, H.; Takahashi, Y.; Ichinose, A.; Iwaki, M.; Selva-Nayagam, D.; Leibovitch, I.
Fonte: Dove Medical Press Ltd Publicador: Dove Medical Press Ltd
Tipo: Artigo de Revista Científica
Publicado em //2011 EN
Relevância na Pesquisa
36.46%
Purpose: To evaluate the surgical outcome of deep lateral orbital decompression with or without rim removal. Design: Retrospective case series. Methods: Thirty-two patients (47 orbits) with Graves’ orbitopathy who underwent simple deep lateral decompression or balanced lateral plus medial decompression. Of the 14 patients (24 orbits) who underwent simple deep lateral decompression, 8 (13 orbits) had temporary rim removal and in 6 (11 orbits) the rim was left intact. Of the 18 patients (23 orbits) who underwent a balanced decompression, 7 (9 orbits) had temporary rim removal and in 11 (14 orbits) the rim was left intact. The amount of postoperative reduction in proptosis was compared among these four groups. Results: The average reduction in proptosis in the simple deep lateral decompression group was 5.73 mm (range: 4.0–8.0 mm) in the rim removal group and 4.09 mm (range: 2.5–6.0 mm) in the intact rim group (P = 0.005). The average reduction in proptosis in the balanced decompression group was 6.39 mm (range: 5.0–8.5 mm) in the rim removal group and 5.07 mm (range: 3.0–8.0 mm) in the intact rim group (P = 0.039). There was no statistically significant difference in proptosis reduction between the simple deep lateral decompression with rim removal group and the balanced decompression with an intact rim group (P = 0.220). Conclusion: The rim removal approach allows a more effective decompression than the intact rim approach. Simple deep lateral decompression with rim removal approach has a similar effect to balanced decompression through an intact rim.; Kakizaki H...

Remoção de fitoplancton e microcistina de águas de abastecimento, pela associação das técnicas de flotação por ar dissolvido e oxidação química com cloro e permanganato de potássio; Removal of phytoplankton and microcystin from source water, by assotiation of dissolved air flotation and chemical oxidation with potassium permanganate and chlorine

Perez, Maurício Fernandes
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 16/05/2008 PT
Relevância na Pesquisa
36.49%
O presente trabalho de pesquisa teve como objetivo principal avaliar a remoção de fitoplancton e microcistina em cinco fluxogramas de tratamento de água para abastecimento, que tiveram como seqüência básica as etapas de coagulação, floculação, flotação por ar dissolvido e filtração, complementados com oxidação química em diferentes pontos da seqüência básica de tratamento estabelecida. Os ensaios foram realizados em escala de laboratório, utilizando água de estudo preparada mediante a mistura de água coletada no reservatório de Barra Bonita, no Estado de São Paulo, e cultura com elevada concentração de microcistina preparada em laboratório. A concentração de microcistina na água de estudo foi mantida no intervalo de 14 a 17 µg/L. O cloreto férrico foi utilizado como agente coagulante, o permanganato de potássio e o cloro, na forma de hipoclorito de sódio, foram utilizados como agentes oxidantes. Foi observada eficiência de remoção de fitoplancton de cerca de 99,9% devido às etapas de coagulação, floculação e flotação por ar dissolvido e, conseqüentemente, remoção de microcistina contida no interior das células íntegras. A oxidação com cloro realizada após a filtração, bem como a oxidação com a associação do permanganato de potássio e cloro realizada após a flotação...

Impact of aeration conditions on the removal of low concentrations of nitrogen in a tertiary partially aerated biological filter

Albuquerque, A.; Makinia, J.; Pagilla, K.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2012 ENG
Relevância na Pesquisa
36.45%
A submerged biological aerated filter (BAF) partially aerated was used to study the removal of low concentrations of ammonia nitrogen (0.3 g N/m3 to 30.5 g N/m3) typically found in nutrient enriched river and lake waters, and treated effluents. Four series of experiments were performed with a synthetic wastewater at ammonia loading rates between 6 g N/m3 d and 903 g N/m3 d and C/N ratios from 2 to 20. The results showed that ammonia removal rates reached higher values (172 g N/m3 d to 564 g N/m3 d) for C/N = 2 and lower values (13.6 g N/m3 d to 34.6 g N/m3 d) for C/N = 20. Between 50% and 70% of the ammonia was removed in the upper section of the BAF, where the dissolved oxygen (DO) concentration was over 2.1 g O2/m3 and the biofilm depth ranged from 0.4 to 0.6 mm. At the bottom section of the reactor, simultaneous removal of ammonia and nitrate was observed at the DO concentrations in the range 0.4 g O2/m3 to 0.8 g O2/m3. There was no removal of ammonia nitrogen for loads below 15 g N/m3.d. The results indicate that the removal of nitrogen in partially aerated BAF may not only be explained by the conventional mechanisms of nitrification/denitrification.

Influence of bed media characteristics on ammonia and nitrate removal in shallow horizontal subsurface flow constructed wetlands

Albuquerque, A.; Oliveira, J.; Semitela, S.; Amaral, L.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /12/2009 ENG
Relevância na Pesquisa
36.45%
Two bed media were tested (gravel and Filtralite) in shallow horizontal subsurface flow (HSSF) constructed wetlands in order to evaluate the removal of ammonia and nitrate for different types of wastewater (acetate-based and domestic wastewater) and different COD/N ratios. The use of Filtralite allowed both higher mass removal rates (1.1 g NH4–N m−2 d−1 and 3 g NO3–N m−2 d−1) and removal efficiencies (>62% for ammonia, 90–100% for nitrate), in less than 2 weeks, when compared to the ones observed with gravel. The COD/N ratio seems to have no significant influence on nitrate removal and the removal of both ammonia and nitrate seems to have involved not only the conventional pathways of nitrification–denitrification. The nitrogen loading rate of both ammonia (0.8–2.4 g NH4–N m−2 d−1) and nitrate (0.6–3.2 g NO3–N m−2 d−1) seem to have influenced the respective removal rates.

Removal of pharmaceuticals and personal care products (PPCPs) from urban wastewater in a pilot vertical flow constructed wetland and a sand filter

Matamoros, Víctor; Arias, Carlos; Brix, Hans; Bayona Termens, Josep María
Fonte: American Chemical Society Publicador: American Chemical Society
Tipo: Artículo Formato: 19968 bytes; application/msword
ENG
Relevância na Pesquisa
36.45%
7 pages, 4 tables, 2 figures.-- PMID: 18186355 [PubMed].-- Printed version published on Dec 1, 2007.; Removal efficiencies and elimination kinetics of 13 pharmaceuticals and personal care products (PPCPs) and BOD5, TSS, and ammonium were evaluated in a pilot vertical subsurface-flow constructed wetland (VFCW) and compared with those obtained by a sand filter. On the basis of the observed removals, the PPCPs studied were grouped in relation to their removal efficiency into (i) PPCPs very efficiently removed, that is, >95% removal in one of the systems (caffeine, salicylic acid, methyl dihydrojasmonate, CA-ibuprofen, hydrocinnamic acid, oxybenzone, ibuprofen, OH-ibuprofen); (ii)PPCPs moderately removed, with removals between 70 and 90% in the two systems (naproxen, diclofenac, galaxolide, and tonalide); and finally (iii) PPCPs poorly removed, with elimination rates of <30% (carbamazepine). At design hydraulic loading rate (HLR) the planted VFCW and the nonplanted SF exhibited similar PPCP removal efficiencies, but the VFCW was less sensitive to removal decline in overloading conditions (up to 2 times the design HLR). Moreover, under a clogging simulation, the HLR and the presence of vegetation were some of the key aspects affecting the PPCPs...

Improving ebpr stability in wwtps aiming at simultaneous carbon and nutrient removal: from modelling studies to experimental validation

Guerrero Camacho, Francisco Javier
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
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L'eliminació biològica de nutrients (EBN) a les estacions depuradores d'aigües residuals (EDARs) es considera el procés més rentable y mediambientalment més respectuós per a prevenir l'eutrofització i complir amb els cada cop més restrictius límits d'abocament. L'eliminació biològica de nitrogen (N) ha estat àmpliament estudiada i implementada en nombroses EDARs, tant urbanes com industrials. Contràriament, per a l'eliminació biològica de fòsfor, P, (procés EBPR) no existeixen encara molt exemples de la seva aplicació a escala real, principalment degut a l'aparició de fallades no esperades quan s'integrà amb l'eliminació biològica de N. La presència de nitrat a la fase anaeròbia es considera la principal causa d'aquestes fallades i, tot i la seva importància, els motius que les provoquen no es coneixen en profunditat. La hipòtesi més estesa assenyala que la presència de nitrat en condicions anaeròbies provoca la competència per la font de carboni (DQO) entre els organismes desnitrificants i els acumuladors de P (PAO). No obstant això, l'experiència en plantes reals indica que aquesta hipòtesi no és capaç de descriure l'elevada pèrdua real d'activitat EBPR tenint en compte la quantitat de nitrat present a la fase anaeròbia. Aquesta tesi té com a objectiu entendre els motius subjacents a aquesta perduda d'activitat EBPR i proposar alternatives per a minimitzar les seves causes. Per tal de fer front a aquest objectiu...

Comparative clinical evaluation of chemomechanical caries removal agent Papacarie® with conventional method among rural population in India - in vivo study

Singh, Sanjeet; Singh, Deepti Jawa; Jaidka, Shipra; Somani, Rani
Fonte: UNICAMP/FOP Publicador: UNICAMP/FOP
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; Formato: application/pdf
Publicado em 09/11/2015 POR
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36.51%
The use of minimally invasive procedures and attention to patient comfort are of great importance, especially for dental treatment in young children. This has led to the development of chemomechanical methods for caries removal. Aim: To evaluate and compare the antimicrobial efficacy, efficacy in terms of time consumption and pain perception of chemomechanical caries removal agent Papacarie® and conventional method of caries removal. Methods: Subjects for this study were chosen from children admitted to dental clinic for restorative procedures. Forty children (age 4-8 years) with early childhood caries were included in this study. Two primary teeth with comparable degrees of carious destruction were chosen in each child for caries removal with either Papacarie® or rotary instruments. The time taken for caries removal was measured using stopwatch. Pain response during caries removal was evaluated using the Wong Baker Face Pain Scale. Dentin samples of both groups were taken prior to, and after caries removal for microbiological analysis. Results The time taken for caries removal in chemomechanical caries removal method was three times longer than the conventional method. Pain score during chemomechanical method of caries removal was 1.525 as compared with 6.65 when conventional method was used. The antimicrobial efficacy of chemomechanical caries removal was significantly similar to conventional method. Conclusions: Papacarie® can be an effective clinical alternative treatment for the removal of occlusal dentinal caries in cavitated primary molars.