Microbial processes and bacterial populations associated to anaerobic treatment of sulfate-rich wastewater

A pilot-scale (1.2 m3) anaerobic sequencing batch biofilm reactor (ASBBR) containing mineral coal for biomass attachment was fed with sulfate-rich wastewater at increasing sulfate concentrations. Ethanol was used as the main organic source. Tested COD/sulfate ratios were of 1.8 and 1.5 for sulfate loading rates of 0.65–1.90 kgSO42−/cycle (48 h-cycle) or of 1.0 in the trial with 3.0 gSO42− l−1. Sulfate removal efficiencies observed in all trials were as high as 99%. Molecular inventories indicated a shift on the microbial composition and a decrease on species diversity with the increase of sulfate concentration. Beta-proteobacteria species affiliated with Aminomonas spp. and Thermanaerovibrio spp. predominated at 1.0 gSO42− l−1. At higher sulfate concentrations the predominant bacterial group was Delta-proteobacteria mainly Desulfovibrio spp. and Desulfomicrobium spp. at 2.0 gSO42− l−1, whereas Desulfurella spp. and Coprothermobacter spp. predominated at 3.0 gSO42− l−1. These organisms have been commonly associated with sulfate reduction producing acetate, sulfide and sulfur. Methanogenic archaea (Methanosaeta spp.) was found at 1.0 and 2.0 gSO42− l−1. Additionally, a simplified mathematical model was used to infer on metabolic pathways of the biomass involved in sulfate reduction

Inovação e rendibilidade: o caso das empresas do setor têxtil português

Mestrado em Finanças EmpresariaisEste estudo tem como principal objetivo analisar o contributo da inovação para a rendibilidade empresarial. A revisão da literatura permite identificar um conjunto de atributos que condicionam a rendibilidade (inovação, globalização, vantagens/estratégias competitivas, parcerias/alianças, formação de clusters, empreendedorismo e internacionalização, entre outros), centrando-se este estudo na inovação. A inovação constitui-se o elemento-chave para a melhoria de desempenho das empresas, na medida em que permite agregar valor aos produtos, diferenciá-los dos restantes e aceder a novos conhecimentos e mercados, permite, melhorar os processos, diferenciar os produtos/serviços face aos concorrentes, constituindo-se, deste modo, num fator dinamizador da rendibilidade empresarial. A realização do presente estudo sugere que as empresas inovadoras apresentam maior rendibilidade. Constatou-se também que quanto maior é a dimensão da empresa e a relevância dos mercados externos no seu volume de negócios, maior é a propensão para inovar.Abstract: The main objective of this study's is to analyze the contribution of innovation to corporate profitability. The revision of literature identifies a set of attributes that affect profitability (innovation, globalization, advantages/competitive strategies, partnerships/alliances, clustering, entrepreneurship and internationalization, among others), this study is focused on innovation The innovation constitutes the key element to improving corporate performance, as it allows adding value to products, distinguishing them from the others and access new markets and knowledge, allows, improve processes, differentiate products / services from their competitors, becoming thus a factor to foster corporate profitability. The completion of this study suggests that innovative firms have higher profitability. It was also found that the greater the size of the company and the importance of foreign markets in its turnover, the greater the propensity to innovate

Characterization of immobilized biomass by amplified rDNA restriction analysis (ARDRA) in an anaerobic sequencing-batch biofilm reactor (ASBBR) for the treatment of industrial wastewater

The performance of an anaerobic sequencing-batch biofilm reactor (ASBBR- laboratory scale- 14L )containing biomass immobilized on coal was evaluated for the removal of elevated concentrations of sulfate (between 200 and 3,000 mg SO4-2·L-1) from industrial wastewater effluents. The ASBBR was shown to be efficient for removal of organic material (between 90% and 45%) and sulfate (between 95% and 85%). The microbiota adhering to the support medium was analyzed by amplified ribosomal DNA restriction analysis (ARDRA). The ARDRA profiles for the Bacteria and Archaea domains proved to be sensitive for the determination of microbial diversity and were consistent with the physical-chemical monitoring analysis of the reactor. At 3,000 mg SO4-2·L-1, there was a reduction in the microbial diversity of both domains and also in the removal efficiencies of organic material and sulfate

Removal of ammonium via simultaneous nitrification-denitrification nitrite-shortcut in a single packed-bed batch reactor

A polyurethane packed-bed-biofilm sequential batch reactor was fed with synthetic substrate simulating the composition of UASB reactor effluents. Two distinct ammonia nitrogen concentrations (125 and 250 mg l(-1)) were supplied during two sequential long-term experiments of 160 days each (320 total). Cycles of 24 h under intermittent aeration for periods of 1 h were applied, and ethanol was added as a carbon source at the beginning of each anoxic period. Nitrite was the main oxidized nitrogen compound which accumulated only during the aerated phases of the batch cycle. A consistent decrease of nitrite concentration started always immediately after the interruption of oxygen supply and addition of the electron donor. Removal to below detection limits of all nitrogen soluble forms was always observed at the end of the 24 h cycles for both initial concentrations. Polyurethane packed-bed matrices and ethanol amendments conferred high process stability. Microbial investigation by cloning suggested that nitrification was carried out by Nitrosomonas-like species whereas denitrification was mediated by unclassified species commonly observed in denitrifying environments. The packed-bed batch bioreactor favored the simultaneous colonization of distinct microbial groups within the immobilized microbial biomass. The biofilm was capable of actively oxidizing ammonium and denitrification at high ratios in intermittent intervals within 24 h cycles. (c) 2008 Elsevier Ltd. All rights reserved.FAPESP (Fundacao de Amparo a Pesquisa do Estado de Sao Paulo)CNPq (Consellho Nacional para o Desenvolvimento Cientifico e Tecnologico

Microbial succession within an anaerobic sequencing batch biofilm reactor (asbbr) treating cane vinasse at 55ºc

The aim of this work was to investigate the anaerobic biomass formation capable of treating vinasse from the production of sugar cane alcohol, which was evolved within an anaerobic sequencing batch biofilm reactor (ASBBR) as immobilized biomass oil cubes of polyurethane foam at the temperature of 55 degrees C. The reactor was inoculated with mesophilic granular sludge originally treating poultry slaughterhouse wastewater. The evolution of the biofilm in the polyurethane foam matrices was assessed during seven experimental phases which were thus characterized by the changes in the organic matter concentrations as COD (1.0 to 20.0 g/L). Biomass characterization proceeded with the examination of sludge samples under optical and scanning electron microscopy. The reactor showed high microbial morphological diversity along the trial. The predominance of Methanosaeta-like cells was observed lip to the organic load of 2.5 gCOD/L.d. Oil the other hand, Methanosarcina-like microorganisms were the predominant archaeal population within the foam matrices at high organic loading ratios above 3.3 gCOD/L.d. This was suggested to be associated to a higher specific rate of acetate consumption by the later organisms

Determining the distribution of granule diameter from biological sludge

Anaerobic granule sizes from various types of anaerobic biological wastewater treatments were investigated in order to understand the influence of this characteristic on the performance of the treatment system. To date, there is no standardised methodology in the current literature, which provides details of a process to obtain data, such as a suitable sample volume, a description of the precision and limitations of the techniques used. Therefore, the aim of this protocol is to standardise the granulometry assay that can measure granule sizes accurately and quickly. In addition, the proposed methodology comprises about 1500–3000 granules in a single sample, a representative number compared to the currently applied methodologies. Keywords: Granulometry assay, Granulometric biological sludge, Granules siz