A waste management school approach towards sustainability

Education towards sustainability in Chemical Engineering (CEng) gave birth to awaste management program (WMP) at Instituto Superior de Engenharia do Porto, in Portugal. It involves students, teachers, and laboratory technicians. It aims to enhance the conscientiousness of the decision-maker next generation for saving resources, managing wastes, and at same time to develop applied chemistry understanding. This program was implemented in 1999 and is responsible for management and fate of all inorganic wastewater providing from training experimental activities of the CEng degree. An immediate reduction of wastes at their source was first defined. Wastes were collected separately and were reused, recycled or chemically treated, and after analytically controlled as legally imposed. Solids formed after this program were recycled, purified or followed suitable elimination. Global results point out environmental, pedagogical, and social benefits. Active participants are aware, in agreement, and publicly committed to the WMP.

GFRP waste reinforced polymer mortars: a new waste management solution for GFRP scrap material

To date, glass fibre reinforced polymer (GFRP) waste recycling is very limited and restricted by thermoset nature of binder matrix and lack of economically viable enduse applications for the recyclates. In this study, efforts were made in order to recycle grinded GFRP waste proceeding from pultrusion production scrap, into new and sustainable composite materials. For this purpose, GFRP waste recyclates, a mix of powdered and fibrous materials, were incorporated into polyester based mortars as fine aggregate and filler replacements, at different load contents (between 4% up to 12% of total mass) and particle size distributions. Potential recycling solution was assessed by mechanical behaviour of resultant GFRP waste modified polymer mortars. Test results revealed that GFRP waste filled polymer mortars present improved flexural and compressive behaviour over unmodified polyester based mortars, thus indicating the feasibility of GFRP waste reuse in concrete-polymer composites.

O recurso ao outsourcing na prestação de cuidados de saúde

Nos últimos anos verificou-se uma alteração das condições e modo de funcionamento de empresas e instituições, privadas e públicas, muitas delas através da introdução de novas ferramentas de gestão. De entre elas, podemos destacar o outsourcing, que apesar de não ser um fenómeno actual, é ainda em Portugal uma ferramenta recente e pouco explorada, que pode contribuir de forma decisiva para a modernização, flexibilidade e competitividade das empresas. O presente estudo pretende abordar a contratação de serviços externos nos serviços de saúde públicos, também conhecido como outsourcing, mediante uma análise prática da realidade de uma instituição hospitalar com sete serviços em regime de outsourcing, com recolha dos dados durante o triénio 2008-2010. No Serviço de Urgência durante 2010 o principal prestador recebeu mais 104,28% acima do valor referência/hora, no Serviço de Oftalmologia no ano de 2010 o prestador recebeu um valor superior em 24,91%, no Serviço de Limpeza, Higiene e Conforto é pago ao prestador durante o ano de 2010 um valor superior em 13,85%, no Serviço de Vigilância e Segurança o prestador recebeu durante o ano de 2010 um valor superior em 27,5%, caso a instituição hospitalar optasse por contratar, para os serviços atrás referidos, profissionais para o quadro de pessoal. Ainda em relação ao Serviço de Urgência foi pago mais 21,38% acima do valor de referência publicado por Despacho governamental. Em relação aos Serviços de Lavandaria e de Tratamento de Resíduos Sólidos, não foi possível recolher os dados necessários que pudessem levar a uma conclusão válida sobre os custos pagos pela instituição hospitalar. Pode-se concluir que a contratação de prestadores externos, para os serviços de saúde, essenciais e não essenciais, em regime de outsourcing, revela-se na maioria dos casos analisados a opção menos económica, com custos bastantes elevados.

Sustainable waste recycling solution for the glass fibre reinforced polymer composite materials industry

In this paper the adequacy and the benefit of incorporating glass fibre reinforced polymer (GFRP) waste materials into polyester based mortars, as sand aggregates and filler replacements, are assessed. Different weight contents of mechanically recycled GFRP wastes with two particle size grades are included in the formulation of new materials. In all formulations, a polyester resin matrix was modified with a silane coupling agent in order to improve binder-aggregates interfaces. The added value of the recycling solution was assessed by means of both flexural and compressive strengths of GFRP admixed mortars with regard to those of the unmodified polymer mortars. Planning of experiments and data treatment were performed by means of full factorial design and through appropriate statistical tools based on analyses of variance (ANOVA). Results show that the partial replacement of sand aggregates by either type of GFRP recyclates improves the mechanical performance of resultant polymer mortars. In the case of trial formulations modified with the coarser waste mix, the best results are achieved with 8% waste weight content, while for fine waste based polymer mortars, 4% in weight of waste content leads to the higher increases on mechanical strengths. This study clearly identifies a promising waste management solution for GFRP waste materials by developing a cost-effective end-use application for the recyclates, thus contributing to a more sustainable fibre-reinforced polymer composites industry.

Mechanical behaviour analysis of polyester polymer mortars modified with recycled GFRP waste materials

In this study the effect of incorporation of recycled glass-fibre reinforced polymer (GFRP) waste materials, obtained by means of milling processes, on mechanical behaviour of polyester polymer mortars was assessed. For this purpose, different contents of recycled GFRP waste powder and fibres, with distinct size gradings, were incorporated into polyester based mortars as sand aggregates and filler replacements. Flexural and compressive loading capacities were evaluated and found better than unmodified polymer mortars. GFRP modified polyester based mortars also show a less brittle behaviour, with retention of some loading capacity after peak load. Obtained results highlight the high potential of recycled GFRP waste materials as efficient and sustainable reinforcement and admixture for polymer concrete and mortars composites, constituting an emergent waste management solution.

Recycling of pultrusion production waste into innovative concrete-polymer composite solutions

In this study, the added value resultant from the incorporation of pultrusion production waste into polymer based concretes was assessed. For this purpose, different types of thermoset composite scrap material, proceeding from GFRP pultrusion manufacturing process, were mechanical shredded and milled into a fibrous-powdered material. Resultant GFRP recyclates, with two different size gradings, were added to polyester based mortars as fine aggregate and filler replacements, at various load contents between 4% up to 12% in weight of total mass. Flexural and compressive loading capacities were evaluated and found better than those of unmodified polymer mortars. Obtained results highlight the high potential of recycled GFRP pultrusion waste materials as efficient and sustainable admixtures for concrete and mortar-polymer composites, constituting an emergent waste management solution.

Sectors and routes in solid waste collection

Collecting and transporting solid waste is a constant problem for municipalities and populations in general. Waste management should take into account the preservation of the environment and the reduction of costs. The goal with this paper is to address a real-life solid waste problem. The case reveals some general and specific characteristics which are not rare, but are not widely addressed in the literature. Furthermore, new methods and models to deal with sectorization and routing are introduced, which can be extended to other applications. Sectorization and routing are tackled following a two-phase approach. In the first phase, a new method is described for sectorization based on electromagnetism and Coulomb’s Law. The second phase addresses the routing problems in each sector. The paper addresses not only territorial division, but also the frequency with which waste is collected, which is a critical issue in these types of applications. Special characteristics related to the number and type of deposition points were also a motivation for this work. A new model for a Mixed Capacitated Arc Routing Problem with Limited Multi-Landfills is proposed and tested in real instances. The computational results achieved confirm the effectiveness of the entire approach.

HACCP numa indústria corticeira: implementação, identificação de pontos críticos e proposta de acções correctivas

Mestrado em Engenharia Química

Valorização energética do biogás de um aterro de resíduos sólidos urbanos

Actualmente, a sociedade depara-se com um enorme desafio: a gestão dos resíduos sólidos urbanos. A sua produção tem vindo a aumentar devido à intensificação das actividades humanas nas últimas décadas. A criação de um sistema de gestão dos resíduos é fundamental para definir prioridades nas acções e metas para que haja uma prevenção na produção de resíduos. Os resíduos sólidos urbanos quando dispostos de forma inadequada podem provocar graves impactos ambientais, tendo sido neste trabalho demonstrado que através de uma gestão eficiente destes é possível aproveitar o potencial energético do biogás e consequentemente diminuir o consumo de combustíveis fósseis reduzindo o impacto ambiental. Os aterros sanitários devem funcionar como a ultima etapa do sistema de tratamento dos resíduos sólidos urbanos e são uma alternativa a ter em conta se forem tomadas todas as medidas necessárias. Estima-se que os aterros sejam responsáveis pela produção de 6-20% do metano existente e que contribuam com 3-4% da produção anual de gases efeito de estufa provenientes de actividades antropogénicas1. É, portanto, fundamental proceder a uma impermeabilização do solo e à criação de condições para recolha do biogás produzido durante a decomposição dos resíduos. Foi estimada a produção de biogás, de acordo com o modelo “LandGEM”, no entanto comparando esta produção com a produção medida pelo explorador, constatou-se uma diferença significativa que pode ser justificada pelo: modo de funcionamento do aterro (longos períodos de paragem); desvio dos resíduos rapidamente biodegradáveis para valorização; a existência de uma percentagem superior ao normal de oxigénio no biogás; a utilização de escórias e cinzas, e a correspondente redução da humidade devido ao compactamento exercido sobre os resíduos durante a sua deposição. Visto tratar-se de um estudo de viabilidade económica da valorização do biogás, foram propostos três cenários para a valorização do biogás. O 1º cenário contempla a instalação de um sistema gerador de energia para comercialização junto da Rede Eléctrica Nacional. O 2º Cenário contempla a instalação de um sistema alternativo de alimentação à caldeira da central de valorização energética de forma a substituir o combustível utilizado actualmente. E o 3º Cenário vem de encontro com os resultados observados actualmente onde se verifica uma reduzida produção/recolha de biogás no aterro. Assim é proposto um sistema gerador de energia que garanta o auto-consumo da exploração do aterro (26 MWh/ano). Qualquer um dos cenários apresenta uma VAL negativa o que leva a concluir que não são viáveis. No entanto, através da análise de sensibilidade, verificamos que estes são claramente afectados por factores como o benefício e o investimento anual, concluindo-se que com alterações nos factores de cálculo, como por exemplo, um aumento no consumo de combustível auxiliar da caldeira (2º cenário), ou com um aumento da factura eléctrica (3º cenário), ou com o aumento do tempo de retorno do investimento inicial(1º cenário), os projectos podem-se tornar viáveis. Por fim importa referir que independentemente da valorização é fundamental continuar a eliminar a máxima quantidade de metano produzida para tentar diminuir o impacto que este tem sobre o ambiente.

Influence of traffic emissions on the carcinogenic polycyclic aromatic hydrocarbons in outdoor breathable particles

Because polycyclic aromatic hydrocarbons (PAHs) have been proven to be toxic, mutagenic, and/or carcinogenic, there is widespread interest in analyzing and evaluating exposure to PAHs in atmospheric environments influenced by different emission sources. Because traffic emissions are one of the biggest sources of fine particles, more information on carcinogenic PAHs associated with fine particles needs to be provided. Aiming to further understand the impact of traffic particulate matter (PM) on human health, this study evaluated the influence of traffic on PM10 (PM with aerodynamic diameter <10 µm) and PM2.5 (PM with aerodynamic diameter <2.5 µm), considering their concentrations and compositions in carcinogenic PAHs. Samples were collected at one site influenced by traffic emissions and at one reference site using lowvolume samplers. Analysis of PAHs was performed by microwave-assisted extraction combined with liquid chromatography (MAE-LC); 17 PAHs, including 9 carcinogenic ones, were quantified. At the site influenced by traffic emissions, PM10 and PM2.5 concentrations were, respectively, 380 and 390% higher than at the background site. When influenced by traffic emissions, the total concentration of nine carcinogenic compounds (naphthalene, chrysene, benzo(a)anthracene, benzo(b) fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, dibenzo(a,h)anthracene, indeno(1,2,3-cd)pyrene, and dibenzo(a,l)pyrene) was increased by 2400 and 3000% in PM10 and PM2.5, respectively; these nine carcinogenic compounds represented 68 and 74% of total PAHs (ƩPAHs) for PM10 and PM2.5, respectively. All PAHs, including the carcinogenic compounds, were mainly present in fine particles. Considering the strong influence of these fine particles on human health, these conclusions are relevant for the development of strategies to protect public health.

An integrated recycling approach for GFRP pultrusion wastes: recycling and reuse assessment into new composite materials using Fuzzy Boolean Nets

In this study, efforts were made in order to put forward an integrated recycling approach for the thermoset based glass fibre reinforced polymer (GPRP) rejects derived from the pultrusion manufacturing industry. Both the recycling process and the development of a new cost-effective end-use application for the recyclates were considered. For this purpose, i) among the several available recycling techniques for thermoset based composite materials, the most suitable one for the envisaged application was selected (mechanical recycling); and ii) an experimental work was carried out in order to assess the added-value of the obtained recyclates as aggregates and reinforcement replacements into concrete-polymer composite materials. Potential recycling solution was assessed by mechanical behaviour of resultant GFRP waste modified concrete-polymer composites with regard to unmodified materials. In the mix design process of the new GFRP waste based composite material, the recyclate content and size grade, and the effect of the incorporation of an adhesion promoter were considered as material factors and systematically tested between reasonable ranges. The optimization process of the modified formulations was supported by the Fuzzy Boolean Nets methodology, which allowed finding the best balance between material parameters that maximizes both flexural and compressive strengths of final composite. Comparing to related end-use applications of GFRP wastes in cementitious based concrete materials, the proposed solution overcome some of the problems found, namely the possible incompatibilities arisen from alkalis-silica reaction and the decrease in the mechanical properties due to high water-cement ratio required to achieve the desirable workability. Obtained results were very promising towards a global cost-effective waste management solution for GFRP industrial wastes and end-of-life products that will lead to a more sustainable composite materials industry.

Gestão de resíduos produzidos num sistema de drenagem e tratamento de águas residuais

O presente trabalho centra-se na gestão de resíduos produzidos no sistema de drenagem e tratamento de águas residuais do município de Vila Nova de Gaia. A entidade onde decorreu o trabalho é uma empresa responsável pela distribuição de água e pela drenagem e tratamento de águas residuais. A empresa está certificada pela norma NP EN ISO 14001, desde 2001, sendo então um dos objectivos o enquadramento da gestão dos resíduos em estudo na referida norma, acompanhando os requisitos da mesma com vista ao seu total cumprimento. Outros dos objectivos foi estudar qual a opção de tratamento mais adequada a aplicar ao resíduo no seu local de armazenamento temporário com vista a minorar os seus impactes ambientais. De acordo com a caracterização analítica do resíduo e com os aspetos legais aplicáveis, foram também analisados os destinos finais possíveis e ambientalmente adequados ao resíduo. A medida proposta para a minimização de impactes no local de armazenamento temporário do resíduo foi a estabilização com cal nos leitos de secagem, disponíveis numa antiga ETAR de loteamento. O doseamento de cal a aplicar ao resíduo será de 10 kg de cal apagada comercial (Ca (OH)2) por uma tonelada de resíduo fresco com um período mínimo de secagem de 2 meses. Outra das medidas de minimização de impactes selecionada foi a implantação de uma cortina arbórea ao redor da instalação. Sendo o resíduo em estudo muito heterogéneo, constituído principalmente por areias, terras e gradados, a valorização foi equacionada mas não foram encontrados alternativas viáveis. O destino final considerado como mais adequado tendo em conta todas as características do resíduo e eluato, analisadas de acordo com o previsto no Decreto-Lei n.º 183/2009 de 10 de Agosto, foi o aterro para resíduos não perigosos. Foi também objecto do estudo a identificação e análise de todos os aspectos ambientais relacionados com a gestão de resíduos e a avaliação da sua significância. Dos aspectos ambientais identificados como significativos, destacam-se aqueles que ocorrem presentemente, os resíduos armazenados (gradados/limpeza de redes), e os que podem ocorrer em situações de emergência, fuga/derrame de óleos/combustíveis e cheiros/odores. De forma a minimizar os aspectos ambientais identificados, e de acordo com a norma NP EN ISO 14001, foram propostas ações que constam de um programa de gestão elaborado para este trabalho, onde se definem os objectivos, metas e prazos. As principais medidas propostas no programa de gestão foram: Estabilização com cal (inicial e reforço se necessário); melhoria do espaço envolvente; análise de questões de saúde ocupacional/segurança; adjudicação de prestação de serviços da recolha por operador licenciado; implantação da cortina arbórea; registo no SIRAPA; criação de planos de emergência ambiental e de segurança.

New recycling approaches for thermoset polymeric composite wastes – an experimental study on polyester based concrete materials filled with fibre reinforced plastic recyclates

In this study, a new waste management solution for thermoset glass fibre reinforced polymer (GFRP) based products was assessed. Mechanical recycling approach, with reduction of GFRP waste to powdered and fibrous materials was applied, and the prospective added-value of obtained recyclates was experimentally investigated as raw material for polyester based mortars. Different GFRP waste admixed mortar formulations were analyzed varying the content, between 4% up to 12% in weight, of GFRP powder and fibre mix waste. The effect of incorporation of a silane coupling agent was also assessed. Design of experiments and data treatment was accomplished through implementation of full factorial design and analysis of variance ANOVA. Added value of potential recycling solution was assessed by means of flexural and compressive loading capacity of GFRP waste admixed mortars with regard to unmodified polymer mortars. The key findings of this study showed a viable technological option for improving the quality of polyester based mortars and highlight a potential cost-effective waste management solution for thermoset composite materials in the production of sustainable concrete-polymer based products.

Hybrid thermoset polymeric composites – an Innovation towards sustainability

In this study, a new waste management solution for thermoset glass fibre reinforced polymer (GFRP) based products was assessed. Mechanical recycling approach, with reduction of GFRP waste to powdered and fibrous materials was applied, and the prospective added-value of obtained recyclates was experimentally investigated as raw material for polyester based mortars. Different GFRP waste admixed mortar formulations were analyzed varying the content, between 4% up to 12% in weight, of GFRP powder and fibre mix waste. The effect of incorporation of a silane coupling agent was also assessed. Design of experiments and data treatment was accomplished through implementation of full factorial design and analysis of variance ANOVA. Added value of potential recycling solution was assessed by means of flexural and compressive loading capacity of GFRP waste admixed mortars with regard to unmodified polymer mortars. The key findings of this study showed a viable technological option for improving the quality of polyester based mortars and highlight a potential cost-effective waste management solution for thermoset composite materials in the production of sustainable concrete-polymer based products.

Experimental study on polyester based concretes filled with glass fibre reinforced plastic recyclates – a contribution to composite materials sustainability

The development and applications of thermoset polymeric composites, namely fibre reinforced plastics (FRP), have shifted in the last decades more and more into the mass market [1]. Despite of all advantages associated to FRP based products, the increasing production and consume also lead to an increasing amount of FRP wastes, either end-of-lifecycle products, or scrap and by-products generated by the manufacturing process itself. Whereas thermoplastic FRPs can be easily recycled, by remelting and remoulding, recyclability of thermosetting FRPs constitutes a more difficult task due to cross-linked nature of resin matrix. To date, most of the thermoset based FRP waste is being incinerated or landfilled, leading to negative environmental impacts and supplementary added costs to FRP producers and suppliers. This actual framework is putting increasing pressure on the industry to address the options available for FRP waste management, being an important driver for applied research undertaken cost efficient recycling methods. [1-2]. In spite of this, research on recycling solutions for thermoset composites is still at an elementary stage. Thermal and/or chemical recycling processes, with partial fibre recovering, have been investigated mostly for carbon fibre reinforced plastics (CFRP) due to inherent value of carbon fibre reinforcement; whereas for glass fibre reinforced plastics (GFRP), mechanical recycling, by means of milling and grinding processes, has been considered a more viable recycling method [1-2]. Though, at the moment, few solutions in the reuse of mechanically-recycled GFRP composites into valueadded products are being explored. Aiming filling this gap, in this study, a new waste management solution for thermoset GFRP based products was assessed. The mechanical recycling approach, with reduction of GFRP waste to powdered and fibrous materials was applied, and the potential added value of obtained recyclates was experimentally investigated as raw material for polyester based mortars. The use of a cementless concrete as host material for GFRP recyclates, instead of a conventional Portland cement based concrete, presents an important asset in avoiding the eventual incompatibility problems arisen from alkalis silica reaction between glass fibres and cementious binder matrix. Additionally, due to hermetic nature of resin binder, polymer based concretes present greater ability for incorporating recycled waste products [3]. Under this scope, different GFRP waste admixed polymer mortar (PM) formulations were analyzed varying the size grading and content of GFRP powder and fibre mix waste. Added value of potential recycling solution was assessed by means of flexural and compressive loading capacities of modified mortars with regard to waste-free polymer mortars.