The aim of this diploma thesis is to investigate the removability of microplastsic particles with different shapes (fragments, sphers, fibers) by standard water treatment process, such as coagulation, filtration and sedimentation. For the experimental purpose in this study, polyvinyl chloride with a size ≤ 50 μm and a density of 1.38 g/cm3 , was used as a representative of microplastics. The coagulation has been provided by ferric sulphate in pH range 5, 6, 7 and 8 and at a diferent dose of coagulant 20, 40, and 60 mg/l. The study results has shown, that the coagulation efficiency of polyvinyl chloride particles were affected by pH. The optimal value of pH has been 7 at the coagulant dose of 20, 40 and 60 mg/l. The presence of polyvinyl chloride shown a positive effect on coagulation. It has been reflected in a reduction of the residuals of iron concentration after coagulation, at pH 5-7. Solution with polyvinyl chloride contained 1,2 mg/l dissolved organic carbon. After fitlration the concentration decreased up to 70 % at pH 7 at dose of coagulant 40 and 60 mg/l. Experiments have shown that polyvinyl chloride particles are capable of faster sedimentation after coagulation. The flocs formed during coagulation interacted effectively with the polyvinyl chloride particles and facilitate their removal...

Single-use plastic packaging waste is overflowing the Earth’s surface, releasing mi- croplastics that contaminate our food. This poses serious threats and concerns to food safety and security. The project aims to raise public awareness about the issue of microplastic con- tamination in the food system. It will use friendly visual language to help people understand how plastic waste from local recycling stations can end up back on their plates and in their bodies. The outcome of the project is a dining workshop that explores the journey of microplastics into the food system. Visual elements and dishes are used as tools to connect partic- ipants with this complex issue. This enables the audience to learn, think critically and reflect on their daily plastic consumption habits. It inspires them to take responsibility and makea change towards reducing plastic waste. Currently, there is no clear scientific literature on whether there is a potential risk to humans associated with exposure to microplastics in food.

Plastic contamination in cotton is a problem in cotton industry and researchers have worked on this problem with different approaches. This thesis documents the design of mechanical and electronic real-time systems for detecting and removing plastic contaminants. The mechanical system was designed to expose plastic embedded inside the seed cotton to the sensor and to separate plastic contaminated cotton from the process stream. The detection system consisted of an embedded computer interfaced with a USB camera and Neural Network (NN) software running in it. Two NN models were tested, a transfer learning model and a built-from-scratch original model. The original NN model had better performance and accuracy than the transfer learning model. An accuracy 95% was achieved for classifying images containing plastic or not containing plastic with an original model. The plastic removal rate of the overall machine was 68%.

Os plásticos são moléculas poliméricas de cadeia longa. O plástico é versátil, leve, flexível, resistente à umidade, forte e economicamente viavel. Essas qualidades atraentes levam a um consumo excessivo de bens plásticos. No entanto, eles são duráveis e muito dificeis de degradar pelo que os materiais plásticos que são usados na fabricação de tantos produtos se tornam resíduos com poder de permanência. Nossa tremenda atração pelo plástico, juntamente com uma propensão inegável de consumir cada vez mais, descartar, jogar lixo e, assim, poluir, tornou-se uma combinação de natureza letal. A produção anual de plásticos duplicou nos últimos 15 anos, alcançando 245 milhões de toneladas, portanto, uma grande quantidade de plásticos é acumulada no meio ambiente gerando problemas ecológicos. O objetivo do presente estudo foi isolar bactérias de um aterro sanitário e de uma amostra de água contaminada com diesel com potencial para degradar o polietileno e outros plásticos, como o polivinil e o poliuretano. Essas bactérias foram isoladas em Ribeirão Preto, SP, utilizando filmes dos três tipos de plástico como fonte de carbono e meio mínimo de sais (MMS). Após a extração do DNA genômico foi utilizada a técnica de reação em cadeia da polimerase (PCR) para detectar o gene alkB e as bactérias que apresentaram esse gene foram identificadas e incubadas com os filmes dos plásticos (polietileno, poliuretano e policloreto de vinil) e o meio MMS (90mL) por 6 meses. Após a incubação foram realizadas as análises de perda de peso, dos espectros obtidos por Espectroscopia de Infravermelho com Transformada Fourier (EIVTF) e das micrografias obtidas por Microscopia Eletrônica de Varredura (MEV) para avaliar a capacidade de biodegradação dos isolados. Foram realizados também testes de suscetibilidade antimicrobiana para conhecer o perfil de resistência dos isolados. Dois isolados bacterianos apresentaram o gene alkB e foram identificados como Paenibacillus sp. S5 e Bacillus cereus A1, respectivamente, utilizando o sequenciamento do gene 16S rDNA. Após o período de incubação foi detectada uma diferença significativa no peso final em relação ao peso inicial para os 3 tipos de plástico e também foram observadas alterações químicas pela EIVTF, como o aparecimento de novos grupos funcionais e rupturas de ligações, sendo essas alterações mais evidentes para os filmes de polietileno. Através da MEV foram visualizadas mudanças físicas, como formação de poros e fissuras, e colonização bacteriana na superfície plástica em todos os casos, especialmente nos filmes de polietileno. Os resultados mais promissores foram obtidos com o isolado Paenibacillus sp. S5, na biodegradação dos três plásticos testados. Esse isolado apresentou suscetibilidade a todos os antibióticos testados, exceto para amicacina e B. cereus A1 foi resistente a 7 dos 12 antibióticos testados. Portanto, as bactérias do presente estudo, especialmente o Paenibacillus sp. S5 podem ser utilizadas em processos de biodegradação para a eliminação de plásticos do meio ambiente. / Plastics are man-made long chain polymeric molecules. Plastic is versatile, lightweight, flexible, moisture resistant, strong, and relatively inexpensive. Those are the attractive qualities that lead us, around the world, to such a voracious appetite and over-consumption of plastic goods. However, durable and very slow to degrade, plastic materials that are used in the production of so many products all, ultimately, become waste with staying power. Our tremendous attraction to plastic, coupled with an undeniable behavioral propensity of increasingly over-consuming, discarding, littering and thus polluting, has become a combination of lethal nature. The annual production of plastics has doubled over the past 15 years to 245 million tons due to their great physical and chemical properties, thus a large amount of plastic gets accumulated in the environment generating plastic waste ecological problems. The purpose of this study was to isolate bacteria from a waste disposal area and also from diesel contaminated water with potential to degrade polyethylene and other plastics as polyvinyl and polyurethane. These bacteria were isolated in Ribeirão Preto, SP, Brazil using plastic discs as a carbon source and a minimal salt medium (MSM). After genomic DNA extraction, PCR reactions were performed to detect the alkB gene and bacteria that showed this gene were identified and incubated with plastic discs (polyethylene, polyurethane and polyvinyl chloride 5cm discs) and MSM (90mL) for 6 months. After incubation, lose weight measurement analysis, Fourier Transforms Infra-red (FT-IR) analysis, Scanning Electron Microscopy (SEM) analysis and antimicrobial susceptibility tests were performed to evaluate the biodegradation capacity and the resistance profile of the isolates. Five bacteria were isolated from soil however, only one showed the alkB gene. From water just one bacterium was isolated which presented the alkB gene. These bacteria were identified as Paenibacillus sp. S5 and Bacillus cereus A1 respectively using the 16S rDNA gene sequencing. A significant difference in final weight compared to initial weight was assessed for the 3 types of plastic in both cases. Chemical changes were observed by FTIR. The appearance of new functional groups and bond scissions were more evident for polyethylene films. SEM visualized physical changes, such as formation of pits and cracks, and bacterial colonization on the plastic surface in all cases especially for polyethylene films. Biodegradation experiments demonstrated the best results for Paenibacillus sp. S5 for the three plastics tested. Paenibacillus sp. S5 showed susceptibility to all antibiotics tested except to amikacin and B. cereus A1 was resistance to seven from 12 antibiotics tested. Hence these bacteria, especially Paenibacillus sp. S5 can be used for biodegradation process as a promising tool for the elimination of plastic from the environment