Optimização do tratamento por lamas activadas do efluente líquido da Mundotêxtil

A Mundotêxtil foi fundada em 1975 tendo iniciado a sua actividade na área comercial de produtos têxteis. Actualmente é o maior produtor nacional de atoalhados de felpo e emprega 575 colaboradores. Como resultado do seu crescimento e sobretudo da actividade de tingimento de fio e felpo, as necessidades de água são consideráveis e o volume de efluentes gerados nos processos industriais é cada vez maior a empresa avançou com a construção de uma estação de tratamento por lamas activadas, colocando-a em funcionamento em Setembro de 2004. Inicialmente surgiram dificuldades para a remoção da cor e da concentração da Carência Química de Oxigénio (CQO) de modo a cumprir os limites máximos de emissão permitidos nas normas de descarga no rio Ave e no Decreto-Lei nº 236/98, de 1 de Agosto. Com a descarga de parte dos efluentes no SIDVA e a utilização de um coagulante adicionado ao reactor o tratamento passou a apresentar melhores resultados. O intuito deste trabalho é o de apresentar soluções de modo a optimizar o funcionamento do tratamento biológico da Mundotêxtil. A optimização pode começar na concepção dos produtos, pode incidir no processo de fabrico para além de poder ser efectuada no seio da estação de tratamento biológico. Foi efectuado um estudo do tratamento biológico por lamas activadas no Laboratório de Tecnologia Química Profª Doutora Lída de Vasconcelos, laboratório tecnológico do Instituto Superior de Engenharia do Porto (ISEP) que decorreu nos meses de Maio, Junho e Julho de 2010. O estudo laboratorial foi efectuado para três situações distintas: 1) tratamento do efluente bruto sem qualquer tipo de pré-tratamento (ensaios 1 a 3); 2) tratamento do efluente bruto submetido a pré-tratamento com coagulante Ambifloc BIO MD (ensaios 4 e 5) e 3) tratamento com adição de fungos ao tanque de arejamento (ensaio 6). Foram utilizadas duas instalações de tratamento alimentadas a partir do mesmo tanque de alimentação. Os dois sistemas eram idênticos, diferiram nos caudais de alimentação de efluente que foram alterados ao longo do estudo. O efluente a tratar foi fornecido pela empresa Mundotêxtil, sendo recolhido por diversas vezes ao longo dos ensaios. Este efluente foi retirado após o pré-tratamento da empresa, ou seja este efluente é o mesmo que alimenta o tratamento biológico da Mundotêxtil. Devido a este facto o efluente usado no estudo laboratorial teve uma variabilidade no período em que decorreu o estudo, nomeadamente em termos de concentração de CQO e cor. A relação entre a Carência Bioquímica (CBO5) e a CQO situouse entre 0,47 e 0,63 o que traduz que está dentro dos valores típicos para um efluente têxtil. Os melhores resultados globais de remoção de CQO foram obtidos no ensaio 5 e estiveram compreendidos entre 73,2% e 77,5% para o ensaio 5.1 e entre 62,9 e 73,2% para o ensaio 5.2. Neste ensaio foi utilizado o coagulante. Todos os valores de concentração de CQO obtidos nos efluentes dos decantadores para os ensaios 2, 5 e 6 são inferiores aos valores limite de descarga definidos nas normas de descarga no rio Ave e o Decreto-Lei 236/98. Os valores de concentração de Sólidos Suspensos Totais (SST), pH, fósforo, CBO5 e cor nos decantadores cumpriram os limites de descarga definidos nas normas de descarga no rio Ave e no Decreto-Lei nº 236/98 em todos os ensaios. Os parâmetros cinéticos obtidos para os ensaios com descorante são os que melhor se ajustam ao projecto de uma instalação de tratamento biológico por lamas activadas do efluente da Mundotêxtil. Os valores obtidos, após ajuste, são os seguintes: k=0,015 L/(mgSSV*d); Sn=12 mg/L; a=0,7982 kgO2/kgCBO5; b=0,0233 [kgO2/(kgSSV*d); y=0,2253 kgSSV/kgCBO5; kd=0,0036 kgSSV/(kgSSV*d. Com base nos parâmetros cinéticos obtiveram-se os seguintes resultados para o projecto de uma estação de tratamento biológico por lamas activadas: · Tempo de retenção hidráulica no reactor de 1,79 d, · Volume do reactor igual a 3643 m3 · Consumo de oxigénio no reactor de 604 kg/d · Razão de recirculação igual a 0,8 · Volume total do decantador secundário igual a 540 m3 · Diâmetro do decantador secundário igual a 15 m A quantidade de oxigénio necessário é baixa e o valor mais adequado deverá ser da ordem de 1200 kg/d. Também foi efectuada uma análise aos produtos químicos consumidos pela empresa na área das tinturarias com a finalidade de identificar as substâncias com uma maior influência potencial no funcionamento da Estação de Tratamento Biológico. O encolante CB, Cera Têxtil P Líquida, Perfemina P-12, Meropan DPE-P, Meropan BRE-P, Indimina STS e Benzym TEC são os produtos químicos que têm uma influência potencial mais significativa na qualidade dos efluentes. Devido ao facto das temperaturas do efluente alimentado ao tratamento biológico da Mundotêxtil oscilarem entre 35 ºC e 43ºC efectuou-se um estudo às necessidades de água quente das tinturarias e por outro lado à capacidade de aquecimento dos efluentes disponíveis. Actualmente a racionalização dos consumos de água é cada vez mais premente, por isso também é apresentado neste trabalho um estudo para a substituição das máquinas convencionais das tinturarias com uma relação de banho 1:10 por máquinas de banho curto (1:6,5). Verifica-se a redução de consumos de 40% de água, 52% de energia eléctrica, 35% de produtos químicos, 51% das necessidades de vapor e por consequência um aumento da produtividade. A empresa pode reduzir os consumos de água em cerca de 280.000 m3/ano. A utilização do pré-tratamento com o coagulante permitirá baixar a concentração da CQO e reduzir a cor à entrada do reactor tratamento biológico. Deste modo é possível manter um tratamento eficiente à saída do tratamento biológico nas situações de descarga de cores carregadas e carga orgânica elevada. Com este conjunto de soluções, quer sejam aplicadas na totalidade ou não, a empresa Mundotêxtil pode enfrentar o futuro com mais confiança podendo estar preparada para fazer face à escassez de água e custos cada vez maiores da energia. Por outro lado pode tratar os seus efluentes a custos menores. A substituição das máquinas de tingimento por máquinas com relação de banho mais baixa (banho curto) implica investimentos elevados mas estes investimentos são necessários não só por motivos ambientais mas também devido à grande competitividade dos mercados.

Otimização da Amostragem e Estudo de Viabilidade da Monitorização de Sondas na ETAR de Rabada

Mestrado em Engenharia Química - Tecnologias de Protecção Ambiental

Modelling of a wastewater treatment plant using GPS-X

Dissertation to obtain the degree of Master in Chemical and Biochemical Engineering

Salinity Intrusion and Seasonal Water Quality Variations in the Tidal Canals of Cochin

The study conducted on the salinity intrusion and seasonal water quality variations in the tidal canals of cochin. The main objectives are, salinity intrusion profile, water quality variation of the surface water of the canals,hierarchical utility of the water bodies and to understand the non-conservative components in the water body. The parameters monitored werepH,temperature,alkalinity,conductivity,DO(dissolvedoxygen),COD(chemical oxygen demand),BOD(biochemical oxygen demand0,chloride, total hardness, calcium hardness, dissolved phosphate, nitrate, total iron, sulphate, turbidity, total coliform and SUVA at 254nm. The tidal canals of GCDA were found to be creeks extending to the interior, canals inter connecting parts of the estuary or canals with seasonally broken segments. Based on utility the canals could be classified as: canals heavely polluted and very saline,canals polluted by urban waste , canals having fresh water for most part of the year and not much polluted, fresh water bodies heavily polluted. During the rainy months carbon fixation by plankton is nonexistent,and during the dry months Chitrapuzha becomes a sink of phosphate. The study indicated abiotic subrouts for dissolved phosphate and revealed the potential pitfalls in LOICZ modeling exercise on sewage ladentidal canals. It was also found that all canals except for the canals of West cochin and chittoorpuzha have fresh water for some part of the year. The water quality index in the durable fresh water stretches was found to be of below average category.

A Study of Single Stage Semi‐Dry Anaerobic Digestion of Organic Fraction of Municipal Solid Waste

Solid waste generation is a natural consequence of human activity and is increasing along with population growth, urbanization and industrialization. Improper disposal of the huge amount of solid waste seriously affects the environment and contributes to climate change by the release of greenhouse gases. Practicing anaerobic digestion (AD) for the organic fraction of municipal solid waste (OFMSW) can reduce emissions to environment and thereby alleviate the environmental problems together with production of biogas, an energy source, and digestate, a soil amendment. The amenability of substrate for biogasification varies from substrate to substrate and different environmental and operating conditions such as pH, temperature, type and quality of substrate, mixing, retention time etc. Therefore, the purpose of this research work is to develop feasible semi-dry anaerobic digestion process for the treatment of OFMSW from Kerala, India for potential energy recovery and sustainable waste management. This study was carried out in three phases in order to reach the research purpose. In the first phase, batch study of anaerobic digestion of OFMSW was carried out for 100 days at 32°C (mesophilic digestion) for varying substrate concentrations. The aim of this study was to obtain the optimal conditions for biogas production using response surface methodology (RSM). The parameters studied were initial pH, substrate concentration and total organic carbon (TOC). The experimental results showed that the linear model terms of initial pH and substrate concentration and the quadratic model terms of the substrate concentration and TOC had significant individual effect (p < 0.05) on biogas yield. However, there was no interactive effect between these variables (p > 0.05). The optimum conditions for maximizing the biogas yield were a substrate concentration of 99 g/l, an initial pH of 6.5 and TOC of 20.32 g/l. AD of OFMSW with optimized substrate concentration of 99 g/l [Total Solid (TS)-10.5%] is a semi-dry digestion system .Under the optimized condition, the maximum biogas yield was 53.4 L/kg VS (volatile solid).. In the second phase, semi-dry anaerobic digestion of organic solid wastes was conducted for 45 days in a lab-scale batch experiment for substrate concentration of 100 g/l (TS-11.2%) for investigating the start-up performances under thermophilic condition (50°C). The performance of the reactor was evaluated by measuring the daily biogas production and calculating the degradation of total solids and the total volatile solids. The biogas yield at the end of the digestion was 52.9 L/kg VS for the substrate concentration of 100 g/l. About 66.7% of volatile solid degradation was obtained during the digestion. A first order model based on the availability of substrate as the limiting factor was used to perform the kinetic studies of batch anaerobic digestion system. The value of reaction rate constant, k, obtained was 0.0249 day-1. A laboratory bench scale reactor with a capacity of 36.8 litres was designed and fabricated to carry out the continuous anaerobic digestion of OFMSW in the third phase. The purpose of this study was to evaluate the performance of the digester at total solid concentration of 12% (semi-dry) under mesophlic condition (32°C). The digester was operated with different organic loading rates (OLRs) and constant retention time. The performance of the reactor was evaluated using parameters such as pH, volatile fatty acid (VFA), alkalinity, chemical oxygen demand (COD), TOC and ammonia-N as well as biogas yield. During the reactor’s start-up period, the process is stable and there is no inhibition occurred and the average biogas production was 14.7 L/day. The reactor was fed in continuous mode with different OLRs (3.1,4.2 and 5.65 kg VS/m3/d) at constant retention time of 30 days. The highest volatile solid degradation of 65.9%, with specific biogas production of 368 L/kg VS fed was achieved with OLR of 3.1 kg VS/m3/d. Modelling and simulation of anaerobic digestion of OFMSW in continuous operation is done using adapted Anaerobic Digestion Model No 1 (ADM1).The proposed model, which has 34 dynamic state variables, considers both biochemical and physicochemical processes and contains several inhibition factors including three gas components. The number of processes considered is 28. The model is implemented in Matlab® version 7.11.0.584(R2010b). The model based on adapted ADM1 was tested to simulate the behaviour of a bioreactor for the mesophilic anaerobic digestion of OFMSW at OLR of 3.1 kg VS/m3/d. ADM1 showed acceptable simulating results.

Nova configuração de um reator compartimentado anaeróbio/aeróbio para o tratamento de esgoto sanitário de baixa carga

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Expressions- und Funktionsanalysen von Neuroglobin und Cytoglobin

Im Rahmen der vorliegenden Dissertation wurden Untersuchungen zur Expression und Funktion der respiratorischen Proteine Neuroglobin (Ngb) und Cytoglobin (Cygb) in Vertebraten durchgeführt. Beide Globine wurden erst kürzlich entdeckt, und ihre Funktionen konnten trotz vorliegender Daten zur Struktur und biochemischen Eigenschaften dieser Proteine bisher nicht eindeutig geklärt werden. Im ersten Abschnitt der vorliegenden Arbeit wurde die zelluläre und subzelluläre Lokalisation von Neuroglobin und Cytoglobin in murinen Gewebeschnitten untersucht. Die Expression von Ngb in neuronalen und endokrinen Geweben hängt offensichtlich mit den hohen metabolischen Aktivitäten dieser Organe zusammen. Insbesondere im Gehirn konnten regionale Unterschiede in der Ngb-Expression beobachtet werden. Dabei korrelierte eine besonders starke Neuroglobin-Expression mit Gehirnbereichen, die bekanntermaßen die höchsten Grundaktivitäten aufweisen. In Anbetracht dessen liegt die Funktion des Neuroglobins möglicherweise im basalen O2-Metabolismus dieser Gewebe, wobei Ngb als O2-Lieferant und kurzfristiger O2-Speicher den vergleichsweise hohen Sauerstoffbedarf vor Ort sicherstellen könnte. Weitere Funktionen in der Entgiftung von ROS bzw. RNS oder die kürzlich publizierte mögliche Rolle des Ngb bei der Verhinderung der Mitochondrien-vermittelten Apoptose durch eine Reduktion des freigesetzten Cytochrom c wären darüber hinaus denkbar. Die Cygb-Expression im Gehirn beschränkte sich auf relativ wenige Neurone in verschiedenen Gehirnbereichen und zeigte dort vorwiegend eine Co-Lokalisation mit der neuronalen NO-Synthase. Dieser Befund legt eine Funktion des Cytoglobins im NO-Metabolismus nahe. Quantitative RT-PCR-Experimente zur mRNA-Expression von Ngb und Cygb in alternden Säugern am Bsp. der Hamsterspezies Phodopus sungorus zeigten keine signifikanten Änderungen der mRNA-Mengen beider Globine in alten im Vergleich zu jungen Tieren. Dies widerspricht publizierten Daten, in denen bei der Maus anhand von Western Blot-Analysen eine Abnahme der Neuroglobin-Menge im Alter gezeigt wurde. Möglicherweise handelt es sich hierbei um speziesspezifische Differenzen. Die im Rahmen dieser Arbeit durchgeführte vergleichende Sequenzanalyse der humanen und murinen NGB/Ngb-Genregion liefert zum einen Hinweise auf die mögliche Regulation der Ngb-Expression und zum anderen eine wichtige Grundlage für die funktionellen Analysen dieses Gens. Es konnte ein minimaler Promotorbereich definiert werden, der zusammen mit einigen konservierten regulatorischen Elementen als Basis für experimentelle Untersuchungen der Promotoraktivität in Abhängigkeit von äußeren Einflüssen dienen wird. Bioinformatische Analysen führten zur Identifizierung des sog. „neuron restrictive silencer element“ (NRSE) im Ngb-Promotor, welches vermutlich für die vorwiegend neuronale Expression des Proteins verantwortlich ist. Die kontrovers diskutierte O2-abhängige Regulation der Ngb-Expression konnte hingegen anhand der durchgeführten komparativen Sequenzanalysen nicht bestätigt werden. Es wurden keine zwischen Mensch und Maus konservierten Bindestellen für den Transkriptionsfaktor HIF-1 identifiziert, der die Expression zahlreicher hypoxieregulierter Gene, z.B. Epo und VEGF, vermittelt. Zusammen mit den in vivo-Daten spricht dies eher gegen eine Regulation der Ngb-Expression bei verminderter Verfügbarkeit von Sauerstoff. Die Komplexität der Funktionen von Ngb und Cygb im O2-Stoffwechsel der Vertebraten macht den Einsatz muriner Modellsysteme unerlässlich, die eine sukzessive Aufklärung der Funktionen beider Proteine erlauben. Die vorliegende Arbeit liefert auch dazu einen wichtigen Beitrag. Die hergestellten „gene-targeting“-Vektorkonstrukte liefern in Verbindung mit den etablierten Nachweisverfahren zur Genotypisierung von embryonalen Stammzellen die Grundlage zur erfolgreichen Generierung von Ngb-knock out sowie Ngb- und Cygb-überexprimierenden transgenen Tieren. Diese werden für die endgültige Entschlüsselung funktionell relevanter Fragestellungen von enormer Bedeutung sein.

Benthic oxygen flixes on the Washington shelf and slope

Benthic oxygen fluxes calculated from in situ microelectrode profiles arc compared with benthic flux chamber O2 uptake measurements on a transect of eight stations across the continental shelf and three stations on the slope of Washington State. Station depths ranged from 40 to 630 m and bottom-water oxygen concentrations were 127-38 µM. The fluxes measured by the two methods were similar on the slope, but on the shelf, the chamber flux exceeded the microelectrode flux by as much as a factor of 3-4. We attribute this difference to pore-water irrigation, a process which apparently accounts for the oxidation of a significant amount of organic C in the continental shelf sediments. Combining our diffusive flux data with other data demonstrates clearly that the bottomwater oxygen concentration must play some significant role in determining the sedimentary oxygen consumption rate. Numerical simulation of the microelectrode 0, profiles suggests that roughly half the diffusive 0, flux must be consumed within - 1 mm of the sediment surface. If this conclusion is correct, then the magnitude of the diffusive flux depends both on the bottom-water oxygen concentration and on the supply rate of labile C to the sediment surf'ace.

Oxygen consumption in Arctic sediments

Total sediment oxygen consumption rates (TSOC or Jtot), measured during sediment-water incubations, and sediment oxygen microdistributions were studied at 16 stations in the Arctic Ocean (Svalbard area). The oxygen consumption rates ranged between 1.85 and 11.2 mmol m**-2 d**-1, and oxygen penetrated from 5.0 to >59 mm into the investigated sediments. Measured TSOC exceeded the calculated diffusive oxygen fluxes (Jdiff) by 1.1-4.8 times. Diffusive fluxes across the sediment-water interface were calculated using the whole measured microprofiles, rather than the linear oxygen gradient in the top sediment layer. The lack of a significant correlation between found abundances of bioirrigating meiofauna and high Jtot/Jdiff ratios as well as minor discrepancies in measured TSOC between replicate sediment cores, suggest molecular diffusion, not bioirrigation, to be the most important transport mechanism for oxygen across the sediment-water interface and within these sediments. The high ratios of Jtot/Jdiff obtained for some stations were therefore suggested to be caused by topographic factors, i.e. underestimation of the actual sediment surface area when one-dimensional diffusive fluxes were calculated, or sampling artifacts during core recovery from great water depths. Measured TSOC correlated to water depth raised to the -0.4 to -0.5 power (TSOC = water depth**-0.4 to -0.5) for all investigated stations, but they could be divided into two groups representing different geographical areas with different sediment oxygen consumption characteristics. The differences in TSOC between the two areas were suggested to reflect hydrographic factors (such as ice coverage and import/production of reactive particulate organic material) related to the dominating water mass (Atlantic or polar) in each of the two areas. The good correlation between TSOC and water depth**-0.4 to -0.5 rules out any of the stations investigated to be topographic depressions with pronounced enhanced sediment oxygen consumption.