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Abstract(s)
A presente dissertação dividiu-se em três objetivos principais. O primeiro objetivo consistiu em avaliar o funcionamento da estação de tratamento de água residuais (ETAR) da empresa Dias Ruivo Lda e estudar e propor alterações ao funcionamento de forma a respeitar valores limite de emissão (VLE) exigidos pelo regulamento interno das condições de afluência de águas residuais às infraestruturas da SIMDOURO. Para esse efeito, recolheram-se amostras de efluente bruto e tratado e determinou-se o teor em sólidos suspensos totais (SST), carência química de oxigénio (CQO), carência biológica de oxigénio (CBO5), teor de crómio, teor de azoto Kjeldhal total (NKJ) e pH. Durante o estudo, a ETAR apresentou eficiências de remoção, para os parâmetros referidos, de 91 %, 63 %, 29%, 98% e 26 %, respetivamente. Os parâmetros CQO, crómio e NKJ apresentaram resultados acima dos VLE com valores médios de 1261,0 mg O2/L, 3,14 mg Cr/L e 142,8 mg NKJ/L, respetivamente. Realizaram-se ensaios experimentais, em batch, de adsorção em carvão ativado e obtiveram-se eficiências de remoção na CQO de 73 %, 42 % no teor de crómio e 39 % no teor de azoto total, demonstrando ser uma tecnologia eficiente para o cumprimento dos VLE exigidos. O segundo objetivo pretendeu avaliar a aplicabilidade de um processo de recurtume compacto de forma a reduzir o impacto ambiental, sem comprometer a qualidade do couro produzido. O processo compacto consegue reduzir o consumo de água em 78 %, o consumo de energia elétrica em 51 %, o de energia térmica em 77 % e gera efluentes líquidos com menor carga poluente por kg de pele tratada. Porém, o couro obtido apresenta, em média, menor resistência à tração e alongamento, menor resistência ao rasgamento por extremidade única e dupla e menor resistência à tração na superfície, quando comparado com o couro obtido pelo processo tradicional. Quanto à solidez à luz artificial, os resultados foram semelhantes. O terceiro objetivo da dissertação consistiu em avaliar a eficiência energética da Dias Ruivo Lda no ano de 2019, utilizando os indicadores de consumo específico de energia (CEE) e intensidade carbónica (IC). Em 2019, a Dias Ruivo Lda apresentou um consumo energético igual a 166 tep/ano não se tratando de uma instalação consumidora intensiva de energia, com CEE de 1,69 kgep/ft2 e IC de 19 730 kg CO2e/tep.
The present dissertation was divided into three main objectives. The first objective was to evaluate the operation of the wastewater treatment plant (WWTP) of the company Dias Ruivo Lda and to study and propose changes to the operation in order to respect the emission limit values (ELV) required by the internal regulation of the conditions for the inflow of waste water to SIMDOURO's infrastructures. For this purpose, samples of raw and treated effluent were taken and the parameters of total suspended solids content (SST), chemical oxygen deficiency (COD), biological oxygen deficiency (BOD5), chromium content, total Kjeldhal nitrogen content (NKJ) and pH were determined. During the study, the WWTP showed removal efficiencies for polluting load equal to 91 %, 63 %, 29 %, 98 %, 26 %, respectively. The parameters COD, chromium and NKJ showed results above the ELV with average values equal to 1261,0 mg O2/L, 3,14 mg Cr/L and 142,8 mg NKJ/L, respectively. Experimental batch adsorption tests were carried out using activated carbon and removal efficiencies were obtained in the COD of 73%, 42% in the chromium content and 39% in the total nitrogen content, proving to be an efficient technology to accomplish required ELVs. The second objective was to evaluate the applicability of a compact retanning process in order to reduce the environmental impact, without compromising the quality of the leather. The compact process manages to reduce water consumption by 78 %, electricity consumption by 51 %, thermal energy by 77 % and generates liquid effluents with less polluting load per kg of skin. However, the obtained leather has less tensile strength and elongation, less tear strength using single and double edge tear.and less resistance to traction on the surface. As for light fastness, the results were similar. The third objective of the dissertation was to assess the energy efficiency of Dias Ruivo Lda in 2019 using the specific energy consumption (SEC) and carbon intensity (CI) indicators. In 2019, Dias Ruivo Lda presented an energy consumption equal to 166 tep/year, not being an energy-intensive installation, with SEC of 1.69 kgep/ft2 and CI of 19 730 kg CO2/tep.
The present dissertation was divided into three main objectives. The first objective was to evaluate the operation of the wastewater treatment plant (WWTP) of the company Dias Ruivo Lda and to study and propose changes to the operation in order to respect the emission limit values (ELV) required by the internal regulation of the conditions for the inflow of waste water to SIMDOURO's infrastructures. For this purpose, samples of raw and treated effluent were taken and the parameters of total suspended solids content (SST), chemical oxygen deficiency (COD), biological oxygen deficiency (BOD5), chromium content, total Kjeldhal nitrogen content (NKJ) and pH were determined. During the study, the WWTP showed removal efficiencies for polluting load equal to 91 %, 63 %, 29 %, 98 %, 26 %, respectively. The parameters COD, chromium and NKJ showed results above the ELV with average values equal to 1261,0 mg O2/L, 3,14 mg Cr/L and 142,8 mg NKJ/L, respectively. Experimental batch adsorption tests were carried out using activated carbon and removal efficiencies were obtained in the COD of 73%, 42% in the chromium content and 39% in the total nitrogen content, proving to be an efficient technology to accomplish required ELVs. The second objective was to evaluate the applicability of a compact retanning process in order to reduce the environmental impact, without compromising the quality of the leather. The compact process manages to reduce water consumption by 78 %, electricity consumption by 51 %, thermal energy by 77 % and generates liquid effluents with less polluting load per kg of skin. However, the obtained leather has less tensile strength and elongation, less tear strength using single and double edge tear.and less resistance to traction on the surface. As for light fastness, the results were similar. The third objective of the dissertation was to assess the energy efficiency of Dias Ruivo Lda in 2019 using the specific energy consumption (SEC) and carbon intensity (CI) indicators. In 2019, Dias Ruivo Lda presented an energy consumption equal to 166 tep/year, not being an energy-intensive installation, with SEC of 1.69 kgep/ft2 and CI of 19 730 kg CO2/tep.
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Keywords
Indústria de Curtumes Impacto Ambiental Tratamento de águas residuais Carvão ativado Processo de recurtume compacto Eficiência energética Tannery Industry Environmental Impact Wastewater Treatment Activated Carbon Compact retanning process Energy Efficiency