Ottimizzazione della reazione di Fenton mediante l’utilizzo di un sistema automatico di reazione

The research presented in this dissertation is aimed to the automation of the Fenton process. The Fenton reaction is finalized to the waste water pre-treatment in order to promote the abatement of the organic contaminants and make it more degradable. Reagents adopted are constituted by a mixture of iron ions and hydrogen peroxide and their effect is strictly influenced by several variables, such as: the reagents molar ratio and their quantities counterpoised to the substrate, temperature, pH, agitation, etc. Therefore, the optimization is far from being considered an easy procedure. The research was carried out using a batch configuration, through which the optimal [Fe2+]/[H2O2] and [substrate]/[H2O2] ratios were identified. Then, in order to improve the process, a semibatch configuration was performed. The preliminary results show that is possible to obtain a greater abatement efficiency for high organic burden using the semibatch configuration here proposed.

Evaluación de vetiver (Chrysopogon zizanioides) y la elefanta (Pennisetum purpureum) en el diseño de humedales artificiales

En este trabajo se presenta la descripción e investigación en la evaluación de vetiver (Chrysopogon zizanioides) y la elefanta (Pennisetum purpureum) en el diseño de humedales artificiales. Para el tratamiento de aguas residuales de origen doméstico, siendo la vegetación uno de los principales componentes de estos sistemas de tratamientos no convencionales. Muchos \sistemas naturales" están siendo considerados con el propósito del tratamiento del agua residual y control de la contaminación del agua, debido a su alta fiabilidad ambiental y los bajos costos de construcción y mantenimiento, es el caso de los humedales artificiales. El interés en los sistemas naturales está basado en la conservación de los recursos asociados con estos sistemas como opuesto al proceso de tratamiento convencional de aguas residuales que es intensivo respecto al uso de energía y químicos. Los wetlands o humedales artificiales constituyen una alternativa de tratamiento debido a su alta eficiencia de remoción de contaminantes, a su bajo costo de instalación y mantenimiento y a su alta fiabilidad ambiental, generalmente un humedal artificial esta constituido por un medio de soporte el cual generalmente es arena o grava, vegetación y microorganismos o biopelícula los cuales llevan los diferentes procesos bioquímicos para remover los contaminantes del afluente. El objetivo general de este trabajo ha sido: Evaluar la eficiencia de remoción de materia orgánica, sólidos, nitrógeno y fósforo total de dos especies de plantas: vetiver (Chrysopogon zizanioides) y la elefanta (Pennisetum purpureum), en el diseño de humedales artificiales para el tratamiento de aguas residuales de origen doméstico. Los humedales artificiales o sistemas pilotos, se encuentran ubicados en la universidad de Medellín y reciben una preparación de agua sintética, que asemeja a las características de un agua residual de origen doméstico. En el presente trabajo se evalúa el porcentaje de remoción de la carga orgánica de aguas residuales, en un sistema de tratamiento por humedales artificiales con dos especies vegetales. El sistema fue diseñado con tres módulos instalados de manera adjunta. En el primero no se integra ninguna especie vegetal, solo el medio de sustrato el cual constituye el blanco (-), en el segundo se integraron organismos de la especie vetiver (Chrysopogon zizanioides), en el tercer sistema piloto, organismos de la especie elefanta (Pennisetum purpureum) y en el cuarto organismos de la especie papiro japones (Cyperus alternifolius), los cuales constituyen el control positivo (+). Los módulos experimentales fueron limpiados, cortados y adecuados acorde al montaje inicial de las plantas y al espacio requerido para su disposición. A cada sistema piloto se le agrega medio de soporte constituido por grava (5 a 10 cm) y arena (15 a 20 cm), el sustrato es evaluado y caracterizado por su diámetro nominal, posterior en cada sistema se siembran las especies en un área de 3x3 y cada humedal por dos semanas se adecua bajo la solución de Hoagland y Arnon y régimen de humedad. En el agua sintética se analizaron los siguientes parámetros: pH, sólidos totales, sólidos suspendido totales, sólidos disueltos totales, demanda química de oxígeno (DQO), demanda bioquímica de oxígeno (DBO5), nitrógeno total (NTK) y fosforo total (PT). También se realizó la determinación del crecimiento de las plantas a partir del incremento de biomasa, porosidad de la raíz y de igual forma se determina NTK y PT. Los resultados demostraron que el sistema es una opción para la remoción de la carga orgánica y de nutrientes en aguas residuales de origen doméstico, de bajo costo de operación y mantenimiento, especialmente se observa que las plantas que crecen en sistemas de régimen de humedad ácuico y ústico, tienden a tener una mayor recepción y adaptación en los humedales artificiales pilotos, es el caso de la elefanta (Pennisetum purpureum), el cual presenta las más altas tasas de remoción de contaminantes y nutrientes en el afluente, seguido por el papiro japonés (Cyperus alternifolius) y el vetiver (Chrysopogon zizanioides), respecto a tasas de remoción. La remoción de contaminantes que se presentan más altos respectivamente, constituyen sólidos en primera instancia, seguido por la demanda bioquímica de oxigeno (DBO5), demanda química de oxígeno (DQO), nitrógeno total (NTK) y fósforo total (PT), estos últimos presentan una baja tasa de remoción, debido a la naturaleza misma del contaminante, a los organismos que realizan la remoción y absorción y al tiempo de retención que se elige, el cual influye en la tasa de remoción del contaminante siendo menor en la concentración de fósforo, pero se encuentranen el rango esperado para estos sistemas de tratamiento no convencionales.

The eutrophication in the river Vouga basin: impacts on the quality of water for public supply

The aim of this paper is to make a characterization of water quality problems, in the river Vouga, regarding its use for public water supply. The river Vouga basin is located in a mountainous area, draining to the coastal lagoon of the Ria de Aveiro. Other medium size rivers also contribute to the load of pollution entering the estuarine system of the Ria de Aveiro. Two major impacts of the pollution in the river Vouga basin were identified. One is the eutrophication process of the lower reach of the river, including the Ria de Aveiro; the other is the occasional deterioration in the quality of the water abstracted from the medium reach of river Vouga. The causes of this deterioration are related to the enrichment of the river water with organic material. To improve the river water quality, both urban wastewater and agriculture related sources, must be controlled.

A framework for better understanding drinking-water quality in Happy Valley-Goose Bay, Labrador: Implications for optimization and protection of municipally supplied water

This research project was driven by the recurring complaints and concerns voiced in the media by residents living in the Valley area of the community of Happy Valley-Goose Bay, Labrador. Drinking water in this town is supplied by two water treatment plants (a municipality treatment plant and a DND treatment plant), which use raw water from two different sources (groundwater from multiple wells versus surface water from Spring Gulch brook) and use two different processes of drinking-water treatment. In fact, the drinking water supplied in the Valley area has a unique distribution arrangement. To meet demand, the Valley area is served by a blend of treated waters from a storage reservoir (Sandhill reservoir), which is fed by both water treatment plants. Most of the time, treated water from the municipal treatment plant dominates in the mixture. As water travels through the distribution system and household plumbing, specific reactions can occur either in the water itself and/or at the solid–liquid interface at the pipe walls; this is strongly influenced by the physical and chemical characteristics of the water. These reactions can introduce undesirable chemical compounds and/or favor the growth of bacteria in the drinking water, causing the deterioration of the quality of water reaching the consumer taps. In the distribution system in general, these chemical constituents and bacteria may pose potential threats to health or the water’s aesthetic qualities (smell, taste or appearance). Drinking water should be not only safe, but also palatable.

Produção de carboidratos a partir do efluente de laticínios tratado por cianobactéria

Nesta tese foi demonstrado o potencial de produção de carboidratos por Aphanothece microscopica Nägeli cultivada no efluente oriundo de uma indústria de laticínios. Para tanto, o trabalho é composto de quatro artigos que objetivaram avaliar a produção de carboidratos em função da temperatura, inóculo e razões C/N e N/P do elfluente, bem como a possibilidade de reúso da água residuária. Foram utilizadas temperaturas de (10, 20 e 30ºC) e inóculo (100, 200 e 300 mg.L-1). A melhor condição indicada foi quando utilizou-se a temperatura de 30°C e 200 mg.L-1 de inóculo. Na sequência, considerando a temperatura e a concentração celular selecionada, foi estudada a influência das razões C/N e N/P na produção de carboidratos. Para tal, C/N (20, 40 e 60) e N/P (5, 10 e 15) na produção de carboidratos extracelulares foram avaliadas em cultivos a 30°C, tendo como inóculo 200 mg.L-1. Os melhores resultados obtidos, foram quando foi utilizado C/N 60 e N/P 10. Uma vez definidas as melhores condições de produção de carboidratos, foi estudado o processo de separação de biomassa do meio de cultivo, a partir dos coagulantes FeCl3, Al2(SO4)3 e tanino. O efeito dos coagulantes na separação da biomassa foram estudados, quanto ao pH (6,0, 7,0 e 8,0) e concentração de coagulantes (50, 300 e 550 mg.L-1), utilizando como parâmetro de medida, a eficiência de remoção de DQO, turbidez e sólidos suspensos (SS). Os resultados demonstraram que as concentrações de coagulantes influenciaram significativamente ao nível de significância de 5 %, na separação da biomassa, com eficiência significativa na remoção da DQO, turbidez e SS. A melhor condição avaliada foi a que utilizou tanino na concentração de 300 mg.L-1 e pH 7,0, o que resultou em uma água residuária com remoção média de 96 % da turbidez, com potencial de ser reutilizada. Por fim, foi realizada a identificação de carboidratos gerados por Aphanothece microscopica Nägeli. Os resultados evidenciaram uma biomassa com até 33,5 % de carboidratos totais, perfazendo uma fração de carboidratos extracelulares, na fase estacionária de crescimento celular, de aproximadamente 25 % e 8 % os carboidratos da parede celular. Ficou demonstrado ainda que a composição dos carboidratos extracelulares do microorganismo em estudo é constituído por mono e dissacarídeos perfazendo concentrações na ordem de 12,88 % de glicose, 3,54 % de rafinose, 3,43 % sacarose, 2,13 % de frutose e 2,45 % de ribose. Ficou demonstrado o potencial de produção de carboidratos por Aphanothece microscopica Nägeli quando cultivada no efluente da indústria de laticínios.

GEOTECHNICAL AND ENVIRONMENTAL IMPACTS OF STEEL SLAG IN EMBANKMENTS

Steel slag is a byproduct of iron and steel production by the metallurgical industries. Annually, 21 million tons of steel slag is produced in the United States. Most of the slag is landfilled, which represents a significant economic loss and a waste of valuable land space. Steel slag has great potential for the construction of highway embankments; however, its use has been limited due to its high swelling potential and alkalinity. The swelling potential of steel slags may lead to deterioration of the structural stability of highways, and high alkalinity poses an environmental challenge as it affects the leaching behavior of trace metals. This study seeks a methodology that promotes the use of steel slag in highway embankments by minimizing these two main disadvantages. Accelerated swelling tests were conducted to evaluate the swelling behavior of pure steel slag and water treatment residual (WTR) treated steel slag, where WTR is an alum-rich by-product of drinking water treatment plants. Sequential batch tests and column leach tests, as well as two different numerical analyses, UMDSurf and WiscLEACH, were carried out to check the environmental suitability of the methods. Tests were conducted to study the effect of a common borrow fill material that encapsulated the slag in the embankment and the effects of two subgrade soils on the chemical properties of slag leachate. The results indicated that an increase in WTR content in the steel slag-WTR mixtures yields a decrease in pH and most of the leached metal concentrations, except aluminum. The change in the levels of pH, after passing through encapsulation and subgrade, depends on the natural pHs of materials.

Material para construção civil a partir de lodo de estação de tratamento de água, lama de polimento de mármore e resíduo de produção de cal

The rapid population growth is the great motivator for the development of the construction industry and the increased demand for drinking water, resulting in a gradual increase in the generation of solid waste. Thus, this work was carried out in order to recycle industrial and municipal wastes incorporating them into materials for civil construction. The composite produced from water treatment sludge and marble polishing mud, applying lime production waste as a binder, was evaluated for its mechanical performance and its morphological structure. The raw materials were characterized for their chemical composition, mineralogy, morphology, particle size and also the moisture content. With the featured materials nine compositions have been developed varying the content of the water treatment sludge between 25 to 50%, marble polishing mud between 35 to 50% and the lime production waste between 10 to 30%. The composites were subjected to mechanical strength tests, water absorption, chemical and mineralogical composition and morphology. The developed materials presented, on the 3rd day of hydration, maximum strength value of 4.65 MPa, the 7th day 6.36 MPa, on the 14th day 6.74 MPa, the 28th day 5.98 MPa, on the 60th day 8.52 MPa at 90th day 11.75 MPa and 180th day 12.06 MPa. The water absorption values after 28 days of hydration ranged from 16.27% to 26.32% and after 90 days, from 13.57% to 23.56%.

Learning Sustainability with EPS@ISEP – Development of a Water Disinfection System

Proceedings of the 8th International Symposium on Project Approaches in Engineering Education (PAEE), Guimarães, 2016

Otimização do método QuEChERS para determinação de agrotóxicos, fármacos e produtos de cuidado pessoal em lodo de ETA por LC-ESI-MS/MS

O lodo gerado em Estação de Tratamento de Água (ETA) durante as etapas de floculação e decantação é classificado como resíduo não inerte. Estudos recentes apontam para uma diminuição na concentração de agrotóxicos, fármacos e Produtos de Cuidado Pessoal (PCP) em águas, após o seu tratamento. Uma possível explicação seja que estes compostos possam estar ficando aderidos ao lodo; entretanto, a investigação desses compostos no lodo de ETA é bastante reduzida. Neste trabalho, foi realizada a otimização do método QuEChERS com determinação por Cromatografia Líquida acoplada a Espectrometria de Massas sequencial para analisar agrotóxicos (atrazina, simazina, clomazona e tebuconazol), fármacos (amitriptilina, cafeína, diclofenaco e ibuprofeno) e PCP (metilparabeno, propilparabeno, triclocarban e bisfenol A) em lodo de ETA, uma matriz bastante complexa, constituída basicamente de compostos inorgânicos (areia, argila e silte) e orgânicos (substâncias húmicas). Após otimizado, o método apresentou limites de quantificação ente 1 e 50 µg kg-1 e as curvas analíticas apresentaram valores de r maiores que 0,98. As recuperações variaram entre 50 e 120% com RSD ≤ 15%. O efeito matriz foi avaliado e observou-se a supressão do sinal para a maioria dos compostos, sendo o efeito compensado utilizando a quantificação por superposição na matriz. O método foi aplicado em amostras de lodo de ETA e foram identificados tebuconazol e metilparabeno em concentrações

Evaluation and measurement of chromium in sea water in order to remove it with mineral absorbent kaolin for desalination

Today, the use of heavy metals and chemical products industry expanded. The presence of significant amounts of, pollutants in industrial waste water can lead to serious risks to the environment and human health have heavy metals like chromium is one example of the future of salmon knock pond environment. Chromium is an essential element in the diet, but high doses of this element is very dangerous. Hence the use of chemical methods as a tool for the removal of metals from waste water pond be used. The aim of this study was to investigate the mineral kaolin adsorbents for the removal of chromium is water. Thus, the effect of different concentrations of absorbent micro amounts of chromium absorption and variable temperature, pH and electrolytes were studied. During the investigation of spectroscopic instrument (Varian) UV-VIS are used. Comparison of the absorption mechanism of chromium adsorption by the adsorbent with nano-absorbent kaolin kaolin was investigated. According to the studies done in the same conditions of temperature, pH and shaking rate of chromium absorption by nano kaolin kaolin is much more attractive. Therefore, its use as an adsorbent abundant, cheap, accessible, efficient and effective is proposed.

Magnetic carbon xerogels for the catalytic wet peroxide oxidation of sulfamethoxazole in environmentally relevant water matrices

Novel magnetic carbon xerogels consisting of interconnected carbon microspheres with iron and/or cobalt microparticles embedded in their structure were developed by a simple route. As inferred from the characterization data, materials with distinctive properties may be directly obtained upon inclusion of iron and/or cobalt precursors during the sol-gel polymerization of resorcinol and formaldehyde, followed by thermal annealing. The unique properties of these magnetic carbon xerogels were explored in the catalytic wet peroxide oxidation (CWPO) of an antimicrobial agent typically found throughout the urban water cycle – sulfamethoxazole (SMX). A clear synergistic effect arises from the inclusion of cobalt and iron in carbon xerogels (CX/CoFe),the resulting magnetic material revealing a better performance in the CWPO of SMX at the ppb level(500 microg L−1) when compared to that of monometallic carbon xerogels containing only iron or cobalt.This effect was ascribed to the increased accessibility of highly active iron species promoted by the simultaneous incorporation of cobalt.The performance of the CWPO process in the presence of CX/CoFe was also evaluated in environmentally relevant water matrices, namely in drinking water and secondary treated wastewater, considered in addition to ultrapure water. It was found that the performance decreases when applied to more complex water and wastewater samples. Nevertheless, the ability of the CWPO technology for the elimination of SMX in secondary treated wastewater was unequivocally shown, with 96.8% of its initial content being removed after 6 h of reaction in the presence of CX/CoFe, at atmospheric pressure, room temperature(T = 25◦C), pH = 3, [H2O2]0= 500 mg L−1and catalyst load = 80 mg L−1. A similar performance (97.8% SMX removal) is obtained in 30 min when the reaction temperature is slightly increased up to 60◦C in an ultra-pure water matrix. Synthetic water containing humic acid, bicarbonate, sulphate or chloride, was also tested. The results suggest the scavenging effect of the different anions considered, as well as the negative impact of dissolved organic matter typically found in secondary treated wastewater, as simulated by the presence of humic acid.An in-situ magnetic separation procedure was applied for catalyst recovery and re-use during reusability cycles performed to mimic real-scale applications. CWPO runs performed with increased SMX concentration (10 mg L−1), under a water treatment process intensification approach, allowed to evalu-ate the mineralization levels obtained, the antimicrobial activity of the treated water, and to propose adegradation mechanism for the CWPO of SMX.

CERAMIC MATERIAL FROM SEWAGE SLUDGE AS SUPPORT MATERIAL SUPPLY WATER FILTRATION

This study shows a possibility of using municipal sewage sludge after thermal treatment in the production of a filtering material to water treatment. Due to the fast urbanization and implementation of high standards for effluent in many countries in recent years, the sewage sludge is being produced in an ever increasing amount. Therefore, the use of sludge is a suitable solution for the expected large quantity of sludge. Dehydration of sludge was performed by controlled heating at temperatures of 1100 degrees C, 850 degrees C, 650 degrees C, 350 degrees C for 3 hours. After thermal treatment the sludge was characterized by X-ray fluorescence, TG/DTG/DTA, residue solubilization and residue lixiviation tests. The aim of the present work was to observe, thought the characterization techniques, if the treated sewage sludge is or not adequate to be used as filter material to water treatment. It will be verified which treatment temperature of the sludge offer possibility to its use in water treatment without carrying pollutants in concentrations out of the standards.

Análise de propriedades térmicas e mecânicas de compósitos de argamassa e resíduo de borracha

Although already to exist alternative technique and economically viable for destination of used tires, quantitative data on properties of constructive elements that use the rubber waste as aggregate still are restricted. In the present work, the waste proceeding from industry of retreading as material for manufacture of composite destined to the production of constructive elements was considered. Mechanical and thermal properties of mortar had been analyzed Portland cement with addition of waste without treatment, in the ratios of 10%, 20% and 30% in mass in relation to the mass of the cement, substituting the aggregate in the trace in mortar 1:5 mass cement and sand. The size of the used residue varied between 0,30mm and 4,8mm (passing in the bolter 4,8mm and being restrained in the one of 0,30mm), being it in the formats fibers and granular. The influences of the size and the percentage of residue added to the mortar (in substitution to the aggregate) in the thermal and mechanical properties had been considered. Assays of body-of-test in thestates had been become fullfilled cool (consistency index) and hardened (absorption of water for capillarity, strength the compression, traction and strength flexural). The work is centralized in the problem of the relation thermal performance /strength mechanics of used constructive systems in regions of low latitudes (Been of the Piauí), characterized for raised indices of solar radiation.