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Efeito do bicarbonato de sódio no tratamento de vinhaça em AnSBBR operado a 55 e 35ºC; Effect of the sodium bicarbonate in the treatment of vinasse in AnSBBR operated at 55 and 35ºC

DÖLL, Maria Magdalena Ribas; FORESTI, Eugenio
Fonte: ABES Publicador: ABES
Tipo: Artigo de Revista Científica
POR
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Avaliou-se a influência do bicarbonato de sódio (NaHCO3) no desempenho do reator anaeróbio batelada sequencial com biomassa imobilizada tratando vinhaça a 55 e a 35ºC. O reator foi preenchido com espuma de poliuretano e agitado a 300 rpm. A adaptação a 55ºC estendeu-se por 50 dias, tendo o reator sido alimentado com vinhaça (DQO de 0,3 a 1,0 g/L). Para a operação a 35ºC, procedeu-se inicialmente ao enriquecimento da população metanogênica, durante 21 dias, com substrato à base de etanol (2,5 gDQO/L). Posteriormente, cargas orgânicas volumétricas (COV) de 0,85 a 5,70 gDQO/L.d foram aplicadas no reator a 55ºC, com suplementação de 1,2 a 0,4 gHCO3-/gDQO. A 35ºC, o reator foi submetido a COV de 2,85 a 36,0 gDQO/L.d com 0,4 a 0,2 gHCO3-/gDQO. A remoção de DQO variou de 43 a 78% a 55ºC e de 75 a 85% a 35ºC. A suplementação de alcalinidade mostrou-se essencial para a estabilidade do processo, sendo requerida em menor quantidade a 35ºC.; The influence of the sodium bicarbonate (NaHCO3) on the performance of an anaerobic sequencing batch biofilm reactor treating vinasse at 55 and 35ºC was evaluated. The reactor was filled with polyurethane foam and agitated at 300 rpm. The acclimatization period at 55ºC lasted 50 days...

Performance and composition of bacterial communities in anaerobic fluidized bed reactors for hydrogen production: Effects of organic loading rate and alkalinity

Shida, Gessia Momoe; Sader, Leandro Takano; Cavalcante de Amorim, Eduardo Lucena; Sakamoto, Isabel Kimiko; Maintinguer, Sandra Imaculada; Saavedra, Nora Katia; Amancio Varesche, Maria Bernadete; Silva, Edson Luiz
Fonte: PERGAMON-ELSEVIER SCIENCE LTD; OXFORD Publicador: PERGAMON-ELSEVIER SCIENCE LTD; OXFORD
Tipo: Artigo de Revista Científica
ENG
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This study evaluated the effects of the organic loading rate (OLR) and pH buffer addition on hydrogen production in two anaerobic fluidized bed reactors (AFBRs) operated simultaneously. The AFBRs were fed with glucose, and expanded clay was used as support material. The reactors were operated at a temperature of 30 degrees C, without the addition of a buffer (AFBR1) and with the addition of a pH buffer (AFBR2, sodium bicarbonate) for OLRs ranging from 19.0 to 140.6 kg COD m(-3) d(-1) (COD: chemical oxygen demand). The maximum hydrogen yields for AFBR1 and AFBR2 were 2.45 and 1.90 mol H-2 mol(-1) glucose (OLR of 84.3 kg COD m(-3) d(-1)), respectively. The highest hydrogen production rates were 0.95 and 0.76 L h(-1) L-1 for AFBR1 and AFBR2 (OLR of 140.6 kg COD m(-3) d(-1)), respectively. The operating conditions in AFBR1 favored the presence of such bacteria as Clostridium, while the bacteria in AFBR2 included Clostridium, Enterobacter, Klebsiella, Veillonellaceae, Chryseobacterium, Sporolactobacillus, and Burkholderiaceae. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.; CNPq; CNPq; CAPES; CAPES; FAPESP; FAPESP

Influência da carga orgânica, da carga de choque, do tempo de alimentação e da suplementação de alcalinidade em um ASBBR com recirculação para tratamento de soro de queijo; Effect of organic load, shock load, feeding time and alkalinity supplementation in an ASBBR with recirculation for cheese whey treatment

Bezerra Junior, Roberto Antonio
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 04/07/2007 PT
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Neste trabalho avaliou-se o desempenho de um reator anaeróbio operado em batelada seqüencial e contendo biomassa imobilizada (ASBBR) em espuma de poliuretano quando submetido a diferentes tempos de alimentação e cargas orgânicas volumétricas, além da aplicação de cargas de choque orgânicas. O reator, com mistura por recirculação da fase líquida e mantido à 30 ± 1 ºC, tratou soro de queijo reconstituído e possuiu 2,5 L de volume reacional. Os resultados mostraram que o tempo de alimentação utilizado exerceu maior influência sobre o desempenho do reator para maiores valores de carga orgânica volumétrica. Durante a operação com carga orgânica volumétrica de 3 gDQO/L.d, a alteração do tempo de alimentação não influenciou na eficiência de remoção de matéria orgânica filtrada, que foi de 98%. Sob carregamento orgânico volumétrico de 6 gDQO/L.d, verificou-se tendência de queda daquela variável para maiores tempos de enchimento: 99, 98 e 97%, para tempos de alimentação de 2, 4 e 6 horas, respectivamente. Na operação com carga orgânica volumétrica de 12 gDQO/L.d, o aumento do tempo de alimentação resultou em queda mais significativa da eficiência de remoção de matéria orgânica filtrada: 97...

Efeito da concentração de glicose e da alcalinidade na produção de hidrogênio em reator anaeróbio de leito fluidificado; Effect of glucose concentration and alkalinity in the hydrogen production in anaerobic fluidized bed

Amorim, Eduardo Lucena Cavalcante 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 12/11/2009 PT
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280.29611%
O objetivo deste estudo foi avaliar o efeito da adição de alcalinidade, da concentração da glicose e da taxa de carregamento orgânico na produção de hidrogênio e ácidos orgânicos em reator anaeróbio de leito fluidificado (RALF), contendo argila expandida (2,8 - 3,35 mm) como material suporte para adesão microbiana. Foram utilizados oito reatores idênticos, sendo quatro deles operados sem adição de alcalinidade, e com concentração de glicose de 2000, 4000, 10000 e 25000 mg/L, respectivamente. Outros quatro reatores operados com adição de alcalinidade, e com as mesmas concentrações de glicose cada um. Os reatores foram inoculados com lodo anaeróbio pré-tratado termicamente, operado com tempo de detenção hidráulica (TDH) decrescente de 8 h a 1 h à temperatura controlada de 30°C. Foi constatada produção volumétrica de hidrogênio máxima de 1,58 L/h.L, para o reator operado com 10000 mg/L de glicose com adição de alcalinidade (R10CA) e um rendimento máximo de 2,52 mol 'H IND.2'/mol glicose, para o reator operado com 4000 mg/L de glicose com adição de alcalinidade (R4CA). O biogás produzido foi composto de 'H IND.2' e 'CO IND.2'. Em ambos os reatores, o conteúdo de hidrogênio aumentou com a redução do TDH de 8 h para 1 h...

Water quality in six sequentially disposed fishponds with continuous water flow

Sipaúba-Tavares, Lúcia Helena; Lourenço, Elaine Mirela; De Souza Braga, Francisco Manoel
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 9-15
ENG
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This study evaluated selected limnological variables in inlet water in six sequentially distributed semi-intensive fishponds. Data were collected during 15 consecutive days in three distinct grow-out periods (May, October and January). Only phosphorus and pH varied among sites and periods (p < 0.01); the opposite (p > 0.05) occurred in the cases of nitrite and dissolved oxygen. No variation was reported with regard to dissolved oxygen, conductivity, alkalinity, free CO2, bicarbonate, chlorophyll-a, nitrite and ammonia did not vary throughout the period (p > 0.05). In May, or rather, the final grow-out period, the fishponds displayed high concentrations, mainly in nitrogen compounds. As from fishpond 3, the inlet water contained high levels of nutrients. The water is passed from pond to pond, evidencing the need for management practices adequate to the specific conditions of each pond. Water quality should be monitored more frequently during high grow-out period when food addition is more intense. Thereafter, more care should be taken, as highest phosphorus concentrations occurred in May.

Influence of inoculum activity on the bio-methanization of a kitchen waste under different waste/inoculum ratios

Neves, L.; Oliveira, Rosário; Alves, M. M.
Fonte: Elsevier ScienceDirect Publicador: Elsevier ScienceDirect
Tipo: Artigo de Revista Científica
Publicado em //2004 ENG
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The use of a granular inoculum prevented acidification during the anaerobic batch biodegradation of a kitchen waste for waste/inoculum ratios in the range of 0.5–2.3 g VS/g VS, when the alkalinity/COD ratio was 37mg NaHCO3/g COD. In similar experiments but using a suspended sludge with a significantly lower activity, the methane production rates and the biodegradability were significantly lower and the pH decreased below 5.5 at the waste/inoculum ratio of 2.3 g VS/g VS. When the added alkalinity was decreased to 2mg NaHCO3/g COD, the ratio waste/inoculum was clearly more important than the inoculum activity, since, irrespective of the sludge used, acidification occurred at waste/inoculum ratios higher than 0.5 g VS/g VS. The advantage of using granular sludge was further investigated in order to define reasonable condition of waste/inoculum ratio and added alkalinity that could be applied in practice. For a waste/inoculum ratio of 1.35, there were no significant differences between the results obtained for the biodegradability and maximum methane production rate (MMPR), when the alkalinity decreased from 44 to 22 mg NaHCO3/g COD.; Fundação para a Ciência e Tecnologia (FCT) - Project POCTI/1999/CTA/36524.

Determination of Alkalinity and dissociation constants of high salinity waters: use of F5BC titration function

Cavalcanti,B.F; Agostinho,L.C.L; Nascimento,L
Fonte: Fundação Editora da Universidade Estadual Paulista Júlio de Mesquita Filho - UNESP Publicador: Fundação Editora da Universidade Estadual Paulista Júlio de Mesquita Filho - UNESP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2010 EN
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371.03117%
Measurements of parameters expressed in terms of carbonic species such as Alkalinity and Acidity of saline waters do not analyze the influence of external parameters to the titration such as Total free and associated Carbonic Species Concentration, activity coefficient, ion pairing formation and Residual Liquid Junction Potential in pH measurements. This paper shows the development of F5BC titration function based on the titrations developed by Gran (1952) for the carbonate system of natural waters. For practical use, samples of saline waters from Pocinhos reservoir in Paraiba were submitted to titration and linear regression analysis. Results showed that F5BC involves F1x and F2x Gran functions determination, respectively, for Alkalinity and Acidity calculations without knowing "a priori" the endpoint of the titration. F5BC also allows the determination of the First and Second Apparent Dissociation Constant of the carbonate system of saline and high ionic strength waters.

The potential of denitrification for the stabilization of activated sludge processes affected by low alkalinity problems

Hoffmann,Heike; Costa,Tatiana Barbosa da; Wolff,Delmira Beatriz; Platzer,Christoph; Costa,Rejane Helena Ribeiro da
Fonte: Instituto de Tecnologia do Paraná - Tecpar Publicador: Instituto de Tecnologia do Paraná - Tecpar
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2007 EN
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In this study, the problems provoked by nitrification of wastewater with low alkalinity were analyzed in a pilot sequencing batch activated sludge reactor (SBR). Decrease in pH resulted in disappearence of protozoa. De-flocculation of the activated sludge floc started below pH 6.5, resulting in enhanced effluent turbidity and loss of bacteria. Nitrification efficiency was affected below pH 6.2. The denitrification activity was not sufficient to keep up the pH, due to a low C/N ratio of the wastewater. Based on alkalinity and ammonia concentration of the wastewater and the necessary denitrification rate to prevent operational problems, was developed a prognostic diagram. The applicability of this diagram was tested for the SBR with excellent results. The diagram could be applied to optimize the operation of wastewater treatment plants affected by problems with low alkalinity wastewater.

Effects of liming and development of Curimbatá (Prochilodus lineatus) larvae on the abundance of zooplankton in fish ponds

Paes,Thécia Alfenas Silva Valente; Paes,José Mauro Valente; Rojas,Nilton Eduardo Torres; Rocha,Odete; Wisniewski,Maria José dos Santos
Fonte: Associação Brasileira de Limnologia Publicador: Associação Brasileira de Limnologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2011 EN
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276.95043%
AIM: We aimed to evaluate the influence of the correction of the water alkalinity in the fish ponds on the density of zooplankton under a period they were stocked with larvae of Prochilodus lineatus, a neotropical fish called "Curimbatá". METHODS: We used a factorial design completely randomized. In one plot (2 ponds) there was no correction of the alkalinity of the water (20 mg CaCO3.L-1) and in two others, this variable was adjusted weekly to values around 30 and 60 mg CaCO3.L-1 ¹, with two replicates each. Zooplankton was sampled weekly and the experiment lasted 63 days. RESULTS: Significant differences in the density of the zooplankton over time (F = 6.78, p < 0.05) were found and there was a sharp decrease in zooplankton density from first to second week, and successive small increases in density from the fourth week until the end of the experiment. When considering the entire study period, alkalinity correction 60 mg CaCO3.L-1 resulted in higher density of zooplankton. Great changes in zooplankton composition occurred. Rotifera were dominant at the beginning of the experiment and Cladocera and Copepoda in the later weeks possibly due to an interplay of dilution by rain and fish predation in the initial part of the experiment and due to both alkalinity correction and predation by both fish and predatory copepods from the fourth week until the end. CONCLUSION: The experiment corroborated the hypothesis that correction of water alkalinity in ponds does favor zooplankton development but also highlighted biotic and abiotic interaction of factors operating simultaneously.

Individual and combined effects of waterlogging and alkalinity on yield of wheat (Triticum aestivum L.) imposed at three critical stages

Sharma, Praveen Kumar; Sharma, S. K.; Choi, I. Y.
Fonte: Springer-Verlag Publicador: Springer-Verlag
Tipo: Artigo de Revista Científica
EN
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Response of wheat genotype HD 2329 to individual and combined effects of alkalinity and waterlogging (WL) at tillering, panicle emergence and anthesis stage was studied. Both stresses increased Na accumulation and reduced K uptake which leads to higher Na+/K+ ratio in the leaves. Yield was decreased under all the stress treatments and highly correlated with Na+/K+ ratio at all the three growth stages (r = −0.83, −0.82 and −0.73, respectively) with maximum reduction under pH 9.4 + WL. Increase in pH from 7.2 to 9.1 and 9.4 delayed complete panicle emergence (4 and 8 days) and flowering (1 and 2 days) at both, tillering and panicle emergence stages. Dual stress further increased days, required for complete panicle emergence and flowering. These results suggested that high Na+/K+ ratio of plant tissue may be the critical factor for growth and development of wheat under WL, alkalinity and dual stress. Due to this delay in flowering and panicle emergence, times required for maturity of grains shorten, resulted in lower grain yield.

Alkalinity to calcium flux ratios for corals and coral reef communities: variances between isolated and community conditions

Murillo, Liana J.A.; Jokiel, Paul L.; Atkinson, Marlin J.
Fonte: PeerJ Inc. Publicador: PeerJ Inc.
Tipo: Artigo de Revista Científica
Publicado em 06/02/2014 EN
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271.03117%
Calcification in reef corals and coral reefs is widely measured using the alkalinity depletion method which is based on the fact that two protons are produced for every mole of CaCO3 precipitated. This assumption was tested by measuring the total alkalinity (TA) flux and Ca2+ flux of isolated components (corals, alga, sediment and plankton) in reference to that of a mixed-community. Experiments were conducted in a flume under natural conditions of sunlight, nutrients, plankton and organic matter. A realistic hydrodynamic regime was provided. Groups of corals were run separately and in conjunction with the other reef components in a mixed-community. The TA flux to Ca2+ flux ratio (ΔTA: ΔCa2+) was consistently higher in the coral-only run (2.06 ± 0.19) than in the mixed-community run (1.60 ± 0.14, p-value = 0.011). The pH was higher and more stable in the mixed-community run (7.94 ± 0.03 vs. 7.52 ± 0.07, p-value = 3 × 10−5). Aragonite saturation state (Ωarag) was also higher in the mixed-community run (2.51 ± 0.2 vs. 1.12 ± 0.14, p-value = 2 × 10−6). The sediment-only run revealed that sediment is the source of TA that can account for the lower ΔTA: ΔCa2+ ratio in the mixed-community run. The macroalgae-only run showed that algae were responsible for the increased pH in the mixed-community run. Corals growing in a mixed-community will experience an environment that is more favorable to calcification (higher daytime pH due to algae photosynthesis...

The Photoprotective Role of Spermidine in Tomato Seedlings under Salinity-Alkalinity Stress

Hu, Lipan; Xiang, Lixia; Zhang, Li; Zhou, Xiaoting; Zou, Zhirong; Hu, Xiaohui
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 23/10/2014 EN
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Polyamines are small, ubiquitous, nitrogenous compounds that scavenge reactive oxygen species and stabilize the structure and function of the photosynthetic apparatus in response to abiotic stresses. Molecular details underlying polyamine-mediated photoprotective mechanisms are not completely resolved. This study investigated the role of spermidine (Spd) in the structure and function of the photosynthetic apparatus. Tomato seedlings were subjected to salinity-alkalinity stress with and without foliar application of Spd, and photosynthetic and morphological parameters were analyzed. Leaf dry weight and net photosynthetic rate were reduced by salinity-alkalinity stress. Salinity-alkalinity stress reduced photochemical quenching parameters, including maximum photochemistry efficiency of photosystem II, quantum yield of linear electron flux, and coefficient of photochemical quenching (qP). Salinity-alkalinity stress elevated nonphotochemical quenching parameters, including the de-epoxidation state of the xanthophyll cycle and nonphotochemical quenching (NPQ). Microscopic analysis revealed that salinity-alkalinity stress disrupted the internal lamellar system of granal and stromal thylakoids. Exogenous Spd alleviated the stress-induced reduction of leaf dry weight...

Alkalinity production in intertidal sands intensified by lugworm bioirrigation

Rao, Alexandra M.F.; Malkin, Sairah Y.; Montserrat, Francesc; Meysman, Filip J.R.
Fonte: Academic Press in association with the Estuarine and Brackish-water Sciences Association Publicador: Academic Press in association with the Estuarine and Brackish-water Sciences Association
Tipo: Artigo de Revista Científica
Publicado em 05/07/2014 EN
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Porewater profiles and sediment-water fluxes of oxygen, nutrients, pH, calcium, alkalinity, and sulfide were measured in intertidal sandflat sediments from the Oosterschelde mesotidal lagoon (The Netherlands). The influence of bioturbation and bioirrigation by the deep-burrowing polychaete Arenicola marina on the rates and sources of benthic alkalinity generation was examined by comparing measurements in intact and defaunated sediment cores before and after the addition of A. marina in summer and fall 2011. Higher organic matter remineralization rates, shallower O2 penetration, and greater sediment-water solute fluxes were observed in summer, consistent with higher sediment community metabolic rates at a higher temperature. Lugworm activity stimulated porewater exchange (5.1 × in summer, 1.9 × in fall), organic matter remineralization (6.2 × in summer, 1.9 × in fall), aerobic respiration (2.4 × in summer, 2.1 × in fall), alkalinity release (4.7 × in summer, 4.0 × in fall), nutrient regeneration, and iron cycling. The effects of lugworm activity on net sediment-water fluxes were similar but more pronounced in summer than in fall. Alkalinity release in fall was entirely driven by metabolic carbonate dissolution...

Clonal Integration Enhances the Performance of a Clonal Plant Species under Soil Alkalinity Stress

Zhang, Wenjun; Yang, Gaowen; Sun, Juanjuan; Chen, Jishan; Zhang, Yingjun
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 19/03/2015 EN
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281.47693%
Clonal plants have been shown to successfully survive in stressful environments, including salinity stress, drought and depleted nutrients through clonal integration between original and subsequent ramets. However, relatively little is known about whether clonal integration can enhance the performance of clonal plants under alkalinity stress. We investigated the effect of clonal integration on the performance of a typical rhizomatous clonal plant, Leymus chinensis, using a factorial experimental design with four levels of alkalinity and two levels of rhizome connection treatments, connected (allowing integration) and severed (preventing integration). Clonal integration was estimated by comparing physiological and biomass features between the rhizome-connected and rhizome-severed treatments. We found that rhizome-connected treatment increased the biomass, height and leaf water potential of subsequent ramets at highly alkalinity treatments but did not affect them at low alkalinity treatments. However, rhizome-connected treatment decreased the root biomass of subsequent ramets and did not influence the photosynthetic rates of subsequent ramets. The biomass of original ramets was reduced by rhizome-connected treatment at the highest alkalinity level. These results suggest that clonal integration can increase the performance of clonal plants under alkalinity stress. Rhizome-connected plants showed dramatically increased survival of buds with negative effects on root weight...

Effect of calcium hydroxide, carbonate and sodium bicarbonate on water quality and zootechnical performance of shrimp Litopenaeus vannamei reared in bio-flocs technology (BFT) systems

Furtado, Plinio Schmidt; Poersh, Luis Henrique da Silva; Wasielesky Junior, Wilson
Fonte: Universidade Federal do Rio Grande Publicador: Universidade Federal do Rio Grande
Tipo: Artigo de Revista Científica
ENG
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Litopenaeus vannamei (the Pacific white shrimp) is the most commonly reared species in super-intensive bio- floc technology (BFT) without water renewal. In BFT, the pH may decrease due to the reduction of alkalinity and the increase of dissolved carbon dioxide. This study evaluated the effects of calcium hydroxide, sodium carbonate and bicarbonate in maintaining water quality during the cultivation of L. vannamei in BFT. The ex- periment was conducted using juveniles stocked in 150-L 12 tanks at a density of 333 shrimp/m 3. There were four treatments with three replicates each: T1 ??? Na2CO3, T2 ??? Ca(OH)2, T3 ??? NaHCO3 and T4 ??? control. For pH correction, alkalinity and both pH and alkalinity corrections, we used sodium carbonate (0.06 g/L), sodi- um bicarbonate (0.20 g/L) and hydrated lime (0.15 g/L), respectively. Significant physical, chemical and bio- logical differences (P b 0.05) were detected among treatments. Control shrimps showed lower growth performance (P b 0.05) than shrimps in other treatments. Hydrated lime and sodium bicarbonate appeared effective in supplementing alkalinity, whereas the soda ash did not. We verified the effectiveness of sodium carbonate in raising pH levels and assisting in supplementing alkalinity. This study demonstrates that the re- sults obtained in the control treatment levels of alkalinity and pH decrease during rearing...

O efeito do hidr??xido de c??lcio, do carbonato e do bicarbonato de s??dio na qualidade de ??gua e no desempenho zoot??cnico do camar??o Litopenaeus vannamei cultivado com tecnologia de bioflocos (BFT)

Furtado, Pl??nio Schmidt
Fonte: Universidade Federal do Rio Grande Publicador: Universidade Federal do Rio Grande
Tipo: Dissertação de Mestrado
POR
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Disserta????o(mestrado)-Universidade Federal do Rio Grande, Programa de P??s???Gradua????o em Aq??icultura, Instituto de Oceanografia, 2011.; O camar??o Litopenaeus vannamei ?? o mais cultivado em sistemas super-intensivos em meio a flocos microbianos (BFT) e sem renova????o de ??gua. Nestes sistemas de bioflocos a tend??ncia natural ?? que ocorra a diminui????o do material carbon??tico ao longo do cultivo, devido aos processos de nitrifica????o que reduzem a alcalinidade na forma de carbonatos e bicarbonatos. Al??m disso, o pH pode diminuir devido a redu????o da alcalinidade e ao ac??mulo de di??xido de carbono dissolvido, proveniente da respira????o. O objetivo do estudo foi avaliar o efeito da aplica????o de hidr??xido de c??lcio, carbonato e bicarbonato de s??dio na qualidade de ??gua do cultivo do L. vannamei em sistema BFT. Para tal, 600 juvenis (6g) foram estocados em 12 tanques com 150L de volume ??til (??=333/m??). Os camar??es foram alimentados duas vezes por dia, com ra????o comercial (Guabi??) seguindo tabela de alimenta????o por 60 dias de experimento. Foram avaliados quatro tratamentos com tr??s repeti????es cada: T1- Na2CO3 (corre????o do pH acima de 7,5); T2- Ca(OH)2 (corre????o da alcalinidade acima de 100mg/L de CaCO3 e pH acima de 7...

Predicting species' tolerance to salinity and alkalinity using distribution data and geochemical modelling: a case study using Australian grasses

Saslis-Lagoudakis, C. H.; Hua, X.; Bui, E.; Moray, C.; Bromham, L.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
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BACKGROUND AND AIMS: Salt tolerance has evolved many times independently in different plant groups. One possible explanation for this pattern is that it builds upon a general suite of stress-tolerance traits. If this is the case, then we might expect a correlation between salt tolerance and other tolerances to different environmental stresses. This association has been hypothesized for salt and alkalinity tolerance. However, a major limitation in investigating large-scale patterns of these tolerances is that lists of known tolerant species are incomplete. This study explores whether species' salt and alkalinity tolerance can be predicted using geochemical modelling for Australian grasses. The correlation between taxa found in conditions of high predicted salinity and alkalinity is then assessed. METHODS: Extensive occurrence data for Australian grasses is used together with geochemical modelling to predict values of pH and electrical conductivity to which species are exposed in their natural distributions. Using parametric and phylogeny-corrected tests, the geochemical predictions are evaluated using a list of known halophytes as a control, and it is determined whether taxa that occur in conditions of high predicted salinity are also found in conditions of high predicted alkalinity. KEY RESULTS: It is shown that genera containing known halophytes have higher predicted salinity conditions than those not containing known halophytes. Additionally...

Red rains as major contributors of nutrients and alkalinity to terrestrial ecosystems at Montseny (NE Spain)

Àvila i Castells, Anna; Rodà, Ferran
Fonte: Universidade Autônoma de Barcelona Publicador: Universidade Autônoma de Barcelona
Tipo: Artigo de Revista Científica Formato: application/pdf
Publicado em //1991 ENG
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During two years (1983-1985), 8 red rains were collected in the Montseny mountains. The suspended matter contained in red rains has its source in the Sahara desert and corresponds to fine silts. Due to the calcite content of dust responsible for the red rains, these rains are alkaline with a volume weighted mean pH of 7.7 versus 4.7 of non-red rains. Estimated HCO; alkalinity input due to red rains is 0.21 keqlhalyr and total annual HCO; alkalinity input is 0.24 keqlhalyr. To that figure, one has to add at least 0.24 keqlhalyr due to the alkalinity of calcite contained in red dust. For the same period, hydrogen input in bulk deposition amounts to 0.19 keqlhalyr. These results indicate that acidity due to non-red rain espisodes is neutralized on an annual basis, with red rains being the major neutralizing agent. Ion concentrations in red rains are high, which makes them an important source of nutrients even though they only account for 5.4% of annual preci itation. Red rains are particularly enriched with ca2+ having a P+ volume-weighted mean Ca concentration 14 times higher than non-red rains and delivering 46% of the annual inputs of soluble ca2+ in bulk precipitation at Montseny.; Durant dos anys (1983-1985) es varen recollir 8 pluges de fang a La Castanya (Montseny). La matèria particulada de les pluges de fang s'origina al desert del Sahara...

Sorption of kraft lignin from spent liquors on pulp fibres

Norgren, Magnus; Bergfors, Erik
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica
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In this investigation, the sorption of kraft lignin (KL) from spent liquors, membrane filtrated and model KL liquors on fully bleached softwood kraft pulp fibres, was studied. The time, temperature and alkalinity during the sorption experiments were chosen to reflect the conditions of black liquor impregnation of chips before the cooking operation. The amount of sorbed KL was estimated by brightness and kappa number measurements. A linear correlation between the k value and the kappa number was found. Among the parameters investigated, the concentration of metal non-process elements was found the most crucial for the sorption of KL on pulp fibres under black liquor impregnation. The influences of KL concentration, metal ion profile and KL molecular weight distribution on the KL sorption behaviour under black liquor impregnation are discussed.

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.