Relationship between flocculation of activated sludge and composition of extracellular polymeric substances

Activated sludge floes are a flocculated mass of microorganisms, extracellular polymeric substances (EPS) and adsorbed organic and inorganic material. The structure of the floes is very heterogeneous and floes with very different properties and morphologies may occur, depending on the conditions in the activated sludge treatment plant and wastewater composition. Present thinking suggests that cations, such as calcium, create cationic bridges with EPS excreted by the bacteria and thereby hold the various floe constituents together. However, due to the complex and heterogeneous nature of activated sludge, the mechanisms have neither been thoroughly investigated nor successfully quantified. A better understanding and description of the biological flocculation process is necessary in order to establish more efficient operational strategies. The main aim of this study was to get a comprehensive and unique insight into the floe properties of activated sludge and to assess the relative impact of chemical and physical parameters. A variety of sludges from full scale treatment plants with different settling properties were characterised. The interrelationships between floe parameters such as composition of EPS, surface properties and floe structure, and their effect on the flocculation and separation properties were assessed. The results indicate that the EPS, both in terms of quantity and quality, are very important for the floe properties of the activated sludge. However, presence of filaments may alter the physical properties of the floes considerably. The EPS showed positive correlations to sludge volume index (SVI) if only sludges with low or moderate numbers of filaments were included. The surface properties were more affected by the composition of the EPS than by the number of filaments. The EPS showed positive correlation to negative surface charge and a negative correlation to relative hydrophobicity and flocculation ability. The negative correlation between flocculation ability and amount of EPS was surprising. The shear sensitivity, measured as degree of erosion of floes when subjected to shear, was more affected by floe size and number of filaments than amount of EPS.

Measuring the accumulated hazards of smoking: global and regional estimates for 2000

Objective: Current prevalence of smoking, even where data are available, is a poor proxy for cumulative hazards of smoking, which depend on several factors including the age at which smoking began, duration of smoking, number of cigarettes smoked per day, degree of inhalation, and cigarette characteristics such as tar and nicotine content or filter type. Methods: We extended the Peto-Lopez smoking impact ratio method to estimate accumulated hazards of smoking for different regions of the world. Lung cancer mortality data were obtained from the Global Burden of Disease mortality database. The American Cancer Society Cancer Prevention Study, phase 11 (CPS-II) with follow up for the years 1982 to 1988 was the reference population. For the global application of the method, never-smoker lung cancer mortality rates were chosen based on the estimated use of coal for household energy in each region. Results: Men in industrialised countries of Europe, North America, and the Western Pacific had the largest accumulated hazards of smoking. Young and middle age males in many regions of the developing world also had large smoking risks. The accumulated hazards of smoking for women were highest in North America followed by Europe. Conclusions: In the absence of detailed data on smoking prevalence and history, lung cancer mortality provides a robust indicator of the accumulated hazards of smoking. These hazards in developing countries are currently more concentrated among young and middle aged males.

��cidos h��micos extra��dos do lodo de esgoto sanit��rio e seus efeitos em plantas

O lodo de esgoto possui alto teor de mat��ria org��nica por��m, tamb��m est��o presentes diferentes poluentes e pat��genos. Desta forma, neste trabalho foi extra��do ��cido h��mico (AH) o qual �� um composto resultante do fracionamento de subst��ncias h��micas que compreendem um grupo de compostos de carbono gerados na decomposi����o de res��duos org��nicos que sofrem ress��ntese formando o h��mus. O ��cido h��mico promove diversos benef��cios nos vegetais, como crescimento, elonga����o celular, toler��ncia a estresses e aumento da permeabilidade da membrana plasm��tica. Com base nestas caracter��sticas, o presente trabalho teve como objetivo avaliar os efeitos citogen��ticos (ensaio Allium cepa), fisiol��gicos, anat��micos e bioqu��micos do ��cido h��mico do lodo de esgoto sanit��rio. Foi realizada caracteriza����o elementar do material para a defini����o das doses. Ap��s 20 dias de tratamento, foram realizadas coletas do material e, posteriormente, analisadas. A caracteriza����o qu��mica do AH indicou-o como bom condicionador para culturas apresentando elevadas taxas de C, H e N. N��o foi observado efeito de toxicidade, citotoxicidade, genotoxicidade e mutagenicidade do AH. Foi verificado aumento expressivo de todos os pigmentos fotossint��ticos vegetais nas concentra����es mais altas (2 mM C L-1 e 4 mM C L-1). Houve aumento da express��o da ATPAse em todos os tratamentos e das enzimas do estresse oxidativo (CAT, SOD, APX, GST) em diferentes concentra����es. A integra����o destas an��lises permitiu concluir que o ��cido h��mico do lodo de esgoto pode ser utilizado como adubo org��nico, pois foi observado benef��cios no vegetal tais como maior crescimento vegetal e aumento da atividade nas enzimas do estresse oxidativo.

Qualidade da ��gua da lagoa Juara (Serra/ES) : avalia����es f��sicas, qu��micas e respostas fisiol��gicas e citogen��ticas em plantas

A gest��o dos recursos h��dricos necessita da integra����o entre os crit��rios f��sicos e qu��micos, e os aspectos bi��ticos, os quais possibilitam identificar os efeitos combinados de subst��ncias e avaliar suas influ��ncias. Os sistemas testes Allium cepa e Tradescantia pallida, s��o utilizados para o estudo da polui����o aqu��tica a partir de aspectos citogen��ticos. Al��m destes biomarcadores, os teores de clorofila tamb��m s��o utilizados em estudos de estresse devido ao reflexo a m��ltiplos fatores. Assim, o objetivo deste trabalho foi avaliar a qualidade da ��gua da lagoa Juara (Munic��pio de Serra/ES) pela an��lise integrada de aspectos f��sicos, qu��micos e ecotoxicol��gicos a partir de estudos citogen��ticos em A. cepa e T. pallida, e fotossint��ticos nesta ��ltima esp��cie. Foram definidas tr��s esta����es amostrais ao longo da lagoa e a partir de amostras de ��gua foram analisados par��metros tais como condutividade, oxig��nio dissolvido, concentra����o de nutrientes e metais. A determina����o dos metais ocorreu por an��lises de espectrometria de massa. O teste do A. cepa foi realizado a partir sementes germinadas em amostras de ��gua da lagoa. Com plantas de T. pallida, foi realizado o ensaio da mitose em ponta de raiz de T. pallida e dosado os teores de pigmentos cloroplast��dicos em folhas totalmente expandidas. Para tanto, foi realizado ensaio utilizando-se a ��gua da lagoa como solvente para solu����o de Hoagland onde estacas previamente enraizadas de T. pallida foram expostas durante 24 horas e 40 dias para as avalia����es citogen��ticas e fotossint��ticas, respectivamente. Foi realizado novo teste do A. cepa nas ��guas da lagoa ap��s os 40 dias de ensaio para aferir a manuten����o das propriedades qu��micas das amostras. A avalia����o citogen��tica nas duas esp��cies envolveu a an��lise dos ��ndice mit��tico (IM), ��ndice de aberra����es cromoss��micas (AC) e frequ��ncia de micron��cleos (MN). Para a an��lise estat��stica foi utilizada a an��lise de vari��ncia seguida pelo teste de Tukey (p < 0.05) para a compara����o dos tratamentos durante a mesma campanha, e teste de Bonferroni (p < 0,05) para a compara����o entre as campanhas. Os resultados f��sicos e qu��micos mensurados demonstram que a lagoa Juara apresenta ind��cios de eutrofica����o artificial. Duas esta����es amostrais, em pelo menos uma campanha amostral, apresentaram potenciais citot��xico, genot��xico e mutag��nico. Todavia, esses potenciais n��o demonstram rela����o com os teores de Fe e Mn quantificados, levando a crer que tais pontos apresentam outros potenciais poluentes. Os danos citogen��ticos observados apresentaram efeitos maximizados durante a segunda campanha, demostrando o efeito do per��odo de chuva na intensifica����o da polui����o nesse ambiente. O estudo do metabolismo fotossint��tico em T. pallida, demonstrou os teores de pigmentos cloroplast��dicos relacionados ao elevado aporte de nutrientes presentes nas esta����es J2 e J3. Sendo o excesso destes, o prov��vel respons��vel pelo teor inferior de pigmentos em J3. Observa-se que os ensaios com A. cepa e T. pallida responderam de maneira fidedigna ao risco potencial do ambiente, complementando as an��lises f��sicas e qu��micas usualmente utilizadas na avalia����o da qualidade da ��gua de ambientes lacustres.

Estudo do transporte atmosf��rico de Mp10 e SO2 com os Modelos WRF/CMAQ em regi��es costeiras urbanas

O objetivo principal deste trabalho foi o estudo do transporte atmosf��rico de PM10 e SO2 em regi��es costeiras urbanas usando modelos WRF/CMAQ. Duas regi��es foram contempladas neste estudo. Uma �� a Regi��o da Grande Vit��ria (RGV), no estado do Esp��rito Santo, Brasil; a outra �� a Regi��o da Grande Dunkerque (RGD), no Departamento Nord Pas-de-Calais, Fran��a. A RGV �� cercada por uma cadeia de montanhas paralela �� costa, resultando num topografia complexa e acidentada. J�� a RGD possui uma topografia muito mais suave. As entradas de dados para os modelos WRF/CMAQ englobaram o invent��rio de emiss��es de poluentes atmosf��ricos do IEMA-ES para a RGV, e o invent��rio de emiss��es no n��vel do solo de Nord Pas-de-Calais denominado ���Cadastre_totaux_3km_A2008 _M2010_V2_SNAPN2��� para a RGD. Ambos os invent��rios apresentaram restri����es, todavia. O invent��rio da RGV apresentou valores de ressuspens��o em vias de tr��fego elevados, em compara����o com diversos estudos, e teve esses dados modificados. Os dados no n��vel do solo e a grande ��rea de das c��lulas da grade (9 km2) do invent��rio da RGD n��o permitiram resultados satisfat��rios de modelagem. A valida����o dos modelos foi realizada por compara����o com resultados obtidos em duas campanhas experimentais: uma na cidade de Dunkerque, no norte da Fran��a, em setembro de 2009; a outra na cidade de Vit��ria, no sudeste do Brasil, em julho de 2012. Esses dados foram obtidos pelo uso de sistemas de Light Detection and Ranging (LIDAR) e Sonic Detection and Ranging (SODAR), bem como de Esta����es Meteorol��gicas de Superf��cie (EMS) e de monitoramento atmosf��rico. Os resultados deste trabalho mostraram que: a) existe uma necessidade de melhorias cont��nuas nos invent��rios regionais de emiss��es, adaptando-os para condi����es locais espec��ficas e focando na obten����o de par��metros necess��rios para modelagem fotoqu��mica; b) os valores de m��dulo e dire����o das velocidades obtidas na modelagem meteorol��gica influenciam fortemente os resultados da modelagem de concentra����o de poluentes; c) a qualidade do ar tanto na RGV quanto na RGD merece aten����o, sobretudo no que diz respeito ��s concentra����es de MP10. De acordo com os dados das esta����es de monitoramento, a situa����o parece mais cr��tica na RGD; d) a modelagem da RGV apresentou resultados mais satisfat��rios do que a da RGD, de acordo com os resultados das valida����es; e) a entrada da brisa do mar provocou altera����es significativas na concentra����o dos poluentes, o que p��de ser observado na an��lise da din��mica da dispers��o de MP10 e SO2. Esse fen��meno foi mais marcante na RGV, onde a entrada da brisa mar��tima provocou um movimento oscilat��rio na pluma de polui����o, levando-a para os bairros mais densamente povoados do conglomerado urbano. Na RGD, a entrada da brisa n��o foi cotidiana e, no dia em que ela aconteceu, houve uma altera����o de quase 180�� na dire����o do movimento da pluma de polui����o. Al��m do aumento da turbul��ncia vertical, o qual j�� foi estudado por diversos autores, este estudo focou tamb��m na influ��ncia brisa do mar na din��mica da pluma de dispers��o de poluentes atmosf��ricos em regi��es costeiras.

Fighting climate change in the air: lessons from the EU directive on global aviation

The European Union's (EU) decision to include aviation into the Emissions Trade Scheme was heatedly contested. Countries around the world, but mainly the Brazil, Russia, India, China and South Africa group (BRICS) and the US, denounced the EU's initiate as illegal and unilateral. Following a decade of frustrated negotiations at the International Civil Aviation Organization (ICAO), this paper interrogates why such measure, in principle climate-friendly, inspired so much global resentment. I argue that concerns with competitiveness and risks of legal inconsistency are important, but insufficient elements to explain the core of the conflict. The paper suggests that the EU was strongly criticized because third countries perceived this action as an imposed solution, which fostered an environment of distrust. Therefore, I claim that the problem has more to do with a normative divide than with a substantive divergence on what should be done regarding aviation emissions. My analysis is informed by the present literature on the links between trade and climate change, but gives particular weight to first-hand information through interviews with key stakeholders. The paper is divided in three parts. First, it presents the scope of the EU directive in historical perspective. Second, it explores the EU's measure through three different angles: legal, economical and political. The final part explores some possible solutions to overcome these divergences.

Economic Analysis of Occupational Risk Prevention in the Construction Sector

The construction sector has one of the worst occupational safety and health records in Europe. The costs of this scenario are very high, namely costs for workers and their families, costs to organizations, resulting from the absence of workers due to illness, insurance premiums, costs resulting from reduced productivity, cost of replacement and training of workers, etc., and costs to society, which in turn increases the costs of health systems. This paper presents and discusses the development of a methodology for economic evaluation in the context of risk management, which will allow senior management to support decision making. The possible application of this methodology to the construction sector is discussed.

Economic analysis of occupational risk prevention: a case study in a textile company

Work accidents affect business and society as a whole. Fewer accidents mean fewer sick leaves, which results in lower costs and less disruption in the production process, with clear advantages for the employer. But workers and their households bear also a significant burden following a work accident, only partially compen-sated by insurance systems. Furthermore, the consequences of work accidents to the State and Society need also to be considered. When an organization performs an integrated risk analysis in evaluating its Occupational Health and Safety Management System, several steps are suggested to address the identified risk situations. Namely, to avoid risks, a series of preventive measures are identified. The organization should make a detailed analysis of the monetary impact (positive or negative) for the organization of each of the measures considered. Particularly, it is also important to consider the impact of each measure on society, involving an adequate eco-nomic cost-benefit analysis. In the present paper, a case study in a textile finishing company is presented. The study concentrates on the dyeing and printing sections. For each of the potential risks, several preventive measures have been identified and the corresponding costs and benefits have been estimated. Subsequently, the Benefit/Cost ratio (B/C) of these measures has been calculated, both in financial terms (from the organisa-tion���s perspective) and in economic terms (including the benefits for the worker and for the Society). Results show that, while the financial analysis in terms of the company does not justify the preventive measures, when the externalities are taken into account, the B/C ratio increases significantly and investments are fully justified.

Developments regarding the integration of the occupational safety and health with quality and environment management systems

Nanotechnology is the manipulation of matter on na almost atomic scale to produce new structures, materials, and devices. As potential occupational exposure to nanomaterials (NMs) becomes more prevalente, it is importante that the principles of medical surveillance and risk management be considered for workers in the nanotechnology industry.However, much information about health risk is beyond our current knowledge. Thus, NMs presente new challenges to understanding, predicting, andmanageing potential health risks. First, we briefly describe some general features of NMs and list the most importante types of NMs. This review discusses the toxicological potential of NMs by comparing possible injury mechanism and know, or potentially adverse, health effects. We review the limited research to date for occupational exposure to these particles and how a worker might be exposed to NMs. The principles of medical surveillance are reviewed to further the discussion of occupational health surveillance are reviewed to further the discussion of occupational health surveillance for workers exposed to NMs. We outlinehow occupational health professionals could contribute to a better knowledge of health effects by the utilization of a health surveillance program and by minimizing exposure. Finally, we discuss the early steps towards regulation and the difficulties facing regulators in controlling potentially harmful exposures in the absence of suficiente scientific evidence.

Integration of risk management in occupational health and safety systems

Risk management can be considered as part of the Occupational Health and Safety System (OHS) of an organization and can be used to develop and implement the OHS policy and manage the associated risks. The success of the integration of risk management in OHS depends on both technical and human aspects. Thus, this paper presents and discusses the case of a company working in the area of solid waste treatment. This company was certified in 2009 with an Integrated Management Systems for Quality, Environment, Occupational Health and Safety. The evolution of accidents before and after the implementation of the integrated system was analysed and a questionnaire was used to capture the perceptions of the technicians on the risk management system. The analysis of the findings showed that the frequency of accidents increased since 2009 but the severity has been reduced. Several interrelated causes and consequences were analysed and discussed. Furthermore, the analysis of the opinions of the company���s technicians permitted to highlight some important aspects on the integration of risk management in the OHS system of the company. In line with this discussion some hypothesis have been formulated.

Economic evaluation of occupational safety preventive measures in a hospital

BACKGROUND: When an organization performs an integrated analysis of risks through its Occupational Health and Safety Management System, several steps are suggested to address the implications of the identified risks. Namely, the organization should make a detailed analysis of the monetary impact for the organization of each of the preventive measures considered. However, it is also important to perform an analysis of the impact of each measure on society (externalities). OBJECTIVE: The aim of this paper is to present a case study related to the application of the proposed economic evaluation methodology. METHODS: An analysis of the work accidents in a hospital has been made. Three of the major types of accidents have been selected: needle stings, falls and excessive strain. Following the risk assessment, some preventive measures have been designed. Subsequently, the Benefit/Cost ratio (B/C) of these measures has been calculated, both in financial terms (from the organization���s perspective) and in economic terms (including the benefits for the worker and for the Society). RESULTS: While the financial ratio is only advantageous in some cases, when the externalities are taken into account, the B/C ratio increases significantly. CONCLUSIONS: It is important to consider external benefits to make decisions concerning the implementation of preventive measures in Occupational Health and Safety projects

Comparison of different methods for the determination of total organic carbon and humic substances in Brazilian soils

ABSTRACTAiming to compare three different methods for the determination of organic carbon (OC) in the soil and fractions of humic substances, seventeen Brazilian soil samples of different classes and textures were evaluated. Amounts of OC in the soil samples and the humic fractions were measured by the dichromate-oxidation method, with and without external heating in a digestion block at 130 ��C for 30 min; by the loss-on-ignition method at 450 ��C during 5 h and at 600 ��C during 6 h; and by the dry combustion method. Dry combustion was used as reference in order to measure the efficiency of the other methods. Soil OC measured by the dichromate-oxidation method with external heating had the highest efficiency and the best results comparing to the reference method. When external heating was not used, the mean recovery efficiency dropped to 71%. The amount of OC was overestimated by the loss-on-ignition methods. Regression equations obtained between total OC contents of the reference method and those of the other methods showed relatively good adjustment, but all intercepts were different from zero (p < 0.01), which suggests that more accuracy can be obtained using not one single correction factor, but considering also the intercept. The Walkley-Black method underestimated the OC contents of the humic fractions, which was associated with the partial oxidation of the humin fraction. Better results were obtained when external heating was used. For the organic matter fractions, the OC in the humic and fulvic acid fractions can be determined without external heating if the reference method is not available, but the humin fraction requires the external heating.

Reported Use of Anabolic Steroids and Ergogenic Substances in Gym/Health Club Settings: Associations with Psychosocial and Exercise Behavior Factors

The industry of ergogenic supplements is increasing rapidly (Cole et al., 2003). Supplements may constitute an important aid for some vigourous exercise routines, but they may also be used as a hypothetical mean to achieve increases in muscular mass. This supposed effect of suplements can lead to its use by individuals who have high levels of drive for muscularity, a condition that is known to be associated with muscular dismorphy (or as it has been called recently vigorexia, Pope et al., 1997). Another psychological factor which can influence supplement consumption is exercise dependence, a borderline problem, as most studies present a prevalence of less than 10% in regular exercisers (Palmeira & Matos, 2006). Symptoms like tolerance or continuity could lead to the use of ergogenic aids to maintain the exercise levels. Also of interest for the understanding of the use of suplements are exercise frequency, volume and intensity, which could explain the ratesof consumption on a more physicological level.

Sistema de apoio �� decis��o espacial para an��lise do impacte ambiental da dispers��o de poluentes atmosf��ricos

Neste artigo e�� apresentado um Sistema de Apoio a�� Decisa��o Espacial (SADE) onde os decisores podem facilmente definir diferentes tipos de problemas espaciais recorrendo a diferentes categorias de objetos, pre��-definidas ou a definir, associando- lhes caracteri��sticas com ou sem depende��ncia espacial, e indicando formas de interfere��ncia (impactos) entre essas caracte- ri��sticas/propriedades. A ana��lise espacial para determinac��a��o ou avaliac��a��o de configurac��o��es alternativas para a localizac��a��o de diferentes tipos de ocorre��ncias espaciais sera�� feita atrave��s da utilizac��a��o interativa do SADE de acordo com conjuntos de regras intri��nsecas aos va��rios elementos gra��ficos (objetos, categorias, caracteri��sticas, impactos) utilizados na definic��a��o dos problemas. O teste a�� generalidade representativa e anali��tica do SADE proposto e�� efectuado recorrendo a um problema concreto, suficientemente especi��fico e complexo, relativo a�� aplicac��a��o de modelos gaussianos para o estudo da dispersa��o atmosfe��rica de eventuais poluentes resultantes do tratamento de resi��duos so��lidos. A regia��o em estudo esta�� limitada, neste exemplo, ao munici��pio de Coimbra, Portugal. Para este munici��pio esta��o acessi��veis, e sa��o utilizados, os dados demogra��ficos ao ni��vel da secc��a��o de voto (censos oficiais) e, como tal, e�� possi��vel a realizac��a��o de um estudo reali��stico do impacto com populac��o��es humanas.