Operating parameters on biological nitrogen removal of water by simultaneous nitrification and denitrification

O nitrogênio é um dos contaminantes mais importantes presentes nas águas residuais. As alternativas tecnológicas mais usuais para o tratamento de águas contendo esse composto lançam mão do ciclo bioquímico do nitrogênio, o qual se sustenta em dois processos, a nitrificação e a desnitrificação. Dentre os parâmetros que influenciam na remoção de nitrogênio, podemos citar a concentração de oxigênio dissolvido, relação carbono/nitrogênio, temperatura, pH entre outros. Este trabalho apresenta uma revisão sobre a remoção biológica de nitrogênio das águas e os principais parâmetros que influenciam na sua remoção, dando ênfase ao processo de nitrificação e desnitrificação simultânea.Nitrogen is one of the most important contaminants present in wastewater. The most common alternative technologies for the treatment of waters containing this compound lay hold of the biochemical cycle of nitrogen, which is based on two processes, nitrification and denitrification. Among the parameters that influence the removal of nitrogen, we can mention the concentration of dissolved oxygen, carbon/nitrogen ratio, temperature, pH, and other relationships. This paper presents an overview of the biological nitrogen removal of water and the main parameters that influence the removal, emphasizing the simultaneous nitrification and denitrification process.Fil: Miranda Zoppas, Fernanda. Universidade Federal do Rio Grande do Sul; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; ArgentinaFil: Bernardes, Andrea Moura. Universidade Federal do Rio Grande do Sul; BrasilFil: Meneguzzi, Álvaro. Universidade Federal do Rio Grande do Sul; Brasi

Effect of operational parameters and Pd/In catalyst in the reduction of nitrate using copper electrode

Water with high concentration of nitrate may cause damage to health and to the environment. This study investigated how concentration, current density, flow, pH, the use of Pd/In catalyst and operating mode (constant current density and constant cell potential) have an influence in the electrochemical reduction of nitrate and in the formation of gaseous compounds using copper electrode. Experiments were performed in two-compartment electrolytic cells separated by a cationic membrane with nitrate model solutions prepared as a surrogate of concentrated brines from membrane desalination plants. The results show that the electroreduction process has potential for reduction of nitrate and that it is influenced by the operational conditions. The best conditions found for the treatment - with satisfactory reduction of nitrate, formation of compounds and reproducibility - were at nitrate concentrations of 600 and 1000 mg.L-1, current density of 1.1 mA.cm-2 and without pH control, since in these conditions the production of gaseous compounds is higher than the production of nitrite. When Pd/In catalyst was used, the nitrate reduction was 50% after 6 hours of experiment and the predominant product were gaseous compounds. When compared to the experiment without the catalyst, the arrangement with Pd/In was the most efficient one.Fil: Beltrame, Thiago Favarini. Ufrgds Lacor; BrasilFil: Coelho, Vanessa. Ufrgds Lacor; BrasilFil: Marder, Luciano. Ufrgds Lacor; BrasilFil: Ferreira, Jane Zoppas. Ufrgds Lacor; BrasilFil: Marchesini, Fernanda Albana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; ArgentinaFil: Bernardes, Andrea Moura. Ufrgds Lacor; Brasi

Removal of entrained organic matter in the copper electrolyte by ozonation

Organic matter-in-aqueous entrainment is a serious problem in the hydrometallurgical extraction of copper from ore. Current inefficiencies, changes in the morphology and orientation of cathode deposit are some of the problems when organic matter is present in the advance electrolyte. In addition, negative effects upon metabolic activity of bioleaching microorganisms are reported due to entrained organic matter in the raffinate electrolyte. In view of these problems, the objective of this study was to evaluate ozonation as an alternative method for the removal of entrained organic matter present in an advanced electrolyte. For this purpose, ozonation during 30 min of synthetic solutions using a bubble glass column reactor at different ozone concentrations, flow rates and temperatures were studied. It was found that the increase in all of these operating parameters is not necessarily associated with an increase of the removal efficiency, and their effects on the mass transfer rate, chemical reaction rate, ozone solubility and contact time play a decisive role in the ozonation process. Thus, the best operating conditions were found at 6.7 wt.%, 1 L min-1 and 27 °C and reached a removal efficiency of 94.5%. This result demonstrated that removal of entrained organic matter in strongly acid solution by ozonation could be an alternative technology

Nitrate reduction by electrochemical processes using copper electrode: Evaluating operational parameters aiming low nitrite formation

This work aims to present different electroreduction and electrocatalytic processes configurations to treat nitrate contaminated water. The parameters tested were: current density, cell potential, electrode potential, pH values, cell type and catalyst use. It was found that the nitrite ion is present in all process variations used, being the resulting nitrite concentration higher in an alkaline pH. The increase in current density on galvanostatic operation mode provides a greater reduction of nitrate (64%, 1.4 mA cm-2) if compared to the potentiostatic (20%) and constant cell potential (37%) configurations. In a dual-chamber cell the nitrate reduction with current density of 1.4 mA cm-2 was tested and obtained as a NO3- reduction of 85%. The use of single chamber cell presented 32 + 3% of nitrate reduction, indicating that in this cell type the nitrate reduction is smaller than in dual-chamber cell (64%). The presence of a Pd catalyst with 3.1% wt. decreased the nitrite (1.0 N-mg L-1) and increased the gaseous compounds (9.4 N-mg L-1) formation. The best configuration showed that, by fixing the current density, the highest nitrate reduction is obtained and the pH presents a significant influence during the tests. The use of the catalyst decreased the nitrite and enhanced the gaseous compounds formation.Fil: Beltrame, Thiago Favarini. Universidade Federal do Rio Grande do Sul; BrasilFil: Miranda Zoppas, Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Ferreira, J. Z.. Universidade Federal do Rio Grande do Sul; BrasilFil: Marchesini, Fernanda Albana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Bernardes, Andrea Moura. Universidade Federal do Rio Grande do Sul; Brasi

Study of the atenolol degradation using a Nb/BDD electrode in a filter-press reactor

[EN] The present paper deals with the atenolol (ATL) degradation by advanced anodic oxidation using a boron-doped diamond anode supported on niobium (Nb/BDD). Cyclic voltammetry performed on this electrode revealed that it presents a high quality (diamond-sp3/sp2-carbon ratio), high potential for OER and that ATL can be oxidized directly and/or indirectly by the electrogenerated oxidants, such as hydroxyl radicals, persulfate ions and sulfate radicals. Electrolysis experiments demonstrated that ATL degradation and mineralization follow a mixed (first and zero) order kinetics depending on the applied current density. At high applied current densities, the amount of OH radicals is very high and the overall reaction is limited by the transport of ATL (pseudo first-order kinetics) whereas for low applied current densities, the rate of OH radicals generation at the anode is slower than the rate of arrival of ATL molecules (pseudo-zero order kinetics). Estimated values of kzero and kfirst based on the assumption of pseudo-zero or pseudo-first order kinetics were carried oud as a function of the supporting electrolyte concentration, indicating that both parameters increased with its concentration due the higher production of sulfate reactive species that play an important role in degradation. Finally, MCE increased with the decrease of current density, due to the lower amount of OH present in solution, since this species could be rapidly wasted in parasitic reactions; and the increase of sulfate concentration due to the more efficient production of persulfate.The authors thank the financial support from the Ministerio de Economía y Competitividad (Spain) under projects CTQ2015-65202-C2-1-R and RTI2018-101341-B-C21, co-financed with FEDER funds. The authors thank to FAPERGS, CAPES, FINEP and CNPQ.Heberle, ANA.; García Gabaldón, M.; Ortega, EM.; Bernardes, AM.; Pérez-Herranz, V. (2019). Study of the atenolol degradation using a Nb/BDD electrode in a filter-press reactor. Chemosphere. 236:1-8. https://doi.org/10.1016/j.chemosphere.2019.07.049S1823

Leadership and nursing work satisfaction: an integrative review

Objective: To identify and analyze knowledge about the relationship between leadership and nursing job satisfaction. Methods: An integrative review of the MEDLINE, CINAHL, EMBASE, PubMed, Web of Science, and LILACS databases to answer the guiding question: What knowledge was produced about the relationship between leadership and nursing job satisfaction in the period from 2011 to 2016? Searches were made to obtain articles, theses, dissertations, and reviews (systematic, narrative and integrative)opinion articles and editorials were excluded. The searches were carried out between October 2016 and January 2017, using the inclusion criteria: primary articlesfull text availablewritten in English, Portuguese or Spanishand published in the last six years (2011-2016). The extraction of study results was carried out by two reviewers, who defined four thematic categories, with the purpose of analyzing the data obtained in the articles and comparing them with the literature. Results: Out of a total of 582 articles, 15 were selectedfour categories were established: the use of the theoretical reference of leadership in the construction of the articlesthe use of instruments to measure leadership and job satisfaction, and the correlation between these variablesthe predominance of nursing leadership in the hospital settingand the direct and indirect relationship between leadership and job satisfaction. Conclusion: The results showed that nursing leadership has a positive and significant impact on job satisfaction, and the need to develop this competency in nursing professionals was demonstrated.Objetivo: Identificar e analisar o conhecimento da relação entre liderança e satisfação no trabalho da enfermagem. Métodos: Revisão integrativa nas bases de dados MEDLINE, CINAHL, EMBASE e LILACS para responder à pergunta norteadora: Qual é o conhecimento produzido acerca da relação entre liderança e satisfação no trabalho da enfermagem no período de 2011 a 2016? Para obtenção dos artigos, excluíram-se as teses, dissertações, revisões (sistemática, narrativa e integrativa), assim como artigos de opinião e editoriais. As buscas ocorreram entre outubro de 2016 a janeiro de 2017, utilizando os critérios de inclusão: artigos primários; disponíveis na íntegra; nos idiomas inglês, português e espanhol e; publicados nos últimos seis anos (2011-2016). A etapa de extração dos resultados dos estudos foram realizadas por dois revisores, que estabeleceram quatro categorias temáticas, com a finalidade de analisar os dados obtidos nos artigos, comparativamente com a literatura. Resultados: Disposto de 582 artigos selecionou-se 15 sendo estabelecidas quatro categorias: o uso do referencial teórico de liderança na construção dos artigos; a utilização de instrumentos para mensurar a liderança e satisfação no trabalho e correlação entre essas variáveis; o predomínio da liderança da enfermagem no contexto hospitalar; e a relação direta e indireta entre liderança e satisfação no trabalho. Conclusão: Evidenciou-se que a liderança na enfermagem exerce uma relação positiva e significativa sobre a satisfação no trabalho demonstrando a necessidade do desenvolvimento dessa competência nos profissionais de enfermagem.Univ Sao Paulo, Escola Enfermagem Ribeirao Preto, Ribeirao Preto, SP, BrazilUniv Fed Sao Paulo, Escola Paulista Enfermagem, Sao Paulo, SP, BrazilUniv Fed Sao Paulo, Escola Paulista Enfermagem, Sao Paulo, SP, BrazilWeb of Scienc

Degradação e inativação de adenovírus na água por fotoeletrooxidação

The present study analyzed the efficiency of the photo-electro-oxidation process as a method for degradation and inactivation of adenovirus in water. The experimental design employed a solution prepared from sterile water containing 5.107 genomic copies/L (gc/L) of a standard strain of human adenovirus type 5 (HAdV-5) divided into two equal parts, one to serve as control and one treated by photo-electro-oxidation (PEO) for 3 hours and with a 5A current. Samples collected throughout the exposure process were analyzed by real-time polymerase chain reaction (qPCR) for viral genome identification and quantitation. Prior to gene extraction, a parallel DNAse treatment step was carried out to assess the integrity of viral particles. Integrated cell culture (ICC) analyses assessed the viability of infection in a cell culture. The tested process proved effective for viral degradation, with a 7 log10 reduction in viral load after 60 minutes of treatment. The DNAse-treated samples exhibited complete reduction of viral load after a 75 minute exposure to the process, and ICC analyses showed completely non-viable viral particles at 30 minutes of treatment.O presente estudo analisou a eficiência do processo de fotoeletrooxidação como metodologia para a degradação e inativação de adenovírus em água. A concepção experimental emprega uma solução preparada a partir de água estéril contendo 5,107 cópias genômicas/L (gc/L) de uma amostra padrão de adenovírus humano tipo 5 (HAdV-5), dividida em duas partes iguais, uma para servir como controle e outra tratada por fotoeletrooxidação (PEO) durante 3 horas e com uma corrente de 5A. As amostras recolhidas durante o processo de exposição foram analisadas por PCR quantitativo em tempo real (qPCR) para identificação e quantificação do genoma viral. Antes da extração de ácidos nucleicos, um passo de tratamento com DNAse paralelo foi realizado para avaliar a integridade das partículas virais. Um ensaio de qPCR integrado à cultura de células (ICC-qPCR) permitiu analisar a viabilidade de infecção em uma cultura de células. O processo mostrou-se eficaz testada para a degradação viral, com uma redução de 7 log10 da carga viral após 60 minutos de tratamento. As amostras tratadas com DNAse exibiram redução completa da carga viral após uma exposição de 75 minutos ao processo, e a análise de ICC-qPCR mostrou partículas virais completamente não-viáveis em 30 minutos de tratamento