Avaliação dos impactos ambientais da tilápia cultivada em sistema semi-intensivo

The main objective of the present study is to assess the physical, chemical and bacteriological characteristics of continuous wastewater and of fish harvesting in tilapia (Oreochromis niloticus) farming, considering the possible effects of wastewater discharges and alternatives to minimize their effects. The samples were collected between April and October, thus spanning the whole developmental cycle of tilapia. The dissolved oxygen demand is the major cause of environmental problems, but the eutrophication index is low despite considerable total phosphorus levels compared to the legal standards established by Resolution 357/05 of the Brazilian National Environmental Council (CONAMA). The environmental pressure index amounted to 2.47, which underscores the necessity for measures that can minimize this impact. The use of wastewaters in irrigation is the best alternative, resulting in rational water use, lower fertilizer utilization rates and reduction of water pollution.O principal objetivo do presente estudo é avaliar as características físicas, químicas e bacteriológicas dos efluentes contínuos e da despesca de peixes como a tilápia (Oreochromis niloticus), analisar os possíveis impactos das descargas de águas residuais e propor alternativas para minimizar os seus efeitos. As amostras foram coletadas entre abril e outubro, abrangendo assim todo o ciclo de desenvolvimento de tilápia. A demanda de oxigênio dissolvido é a principal causa de problemas ambientais, mas o índice de eutrofização é baixo, apesar de apresentar consideráveis níveis de fósforo total em comparação com os padrões legais estabelecidos pela Resolução 357/05 do Conselho Nacional do Meio Ambiente do Brasil (CONAMA). O índice de pressão ambiental elevou-se a 2,47, o que reforça a necessidade de medidas que possam minimizar esse impacto. A utilização de águas residuais na irrigação é a melhor alternativa, resultando em uso racional da água, menores taxas de utilização de fertilizantes e redução da poluição hídrica

AVALIAÇÃO DA EFICIÊNCIA DA MACRÓFITA HYMENACHNE GRUMOSA COMO ORGANISMO TESTE, EM DOIS SISTEMAS DE TRATAMENTO DE EFLUENTES, ATRAVÉS DE ENSAIOS ECOTOXICOLÓGICOS

O trabalho teve como objetivo avaliar a eficiência da macrófita Hymenachne grumosa como teste para remoção de poluentes através de ensaios de toxicidade aguda de duas estações experimentais utilizando Daphnia magna Straus como organismo-teste. Desenho experimental 1 (PA-1), proveniente da Estação de Tratamento de Esgoto (ETE-UNISC), com Wetlands construídos (WC’s), entre abril e setembro de 2010. Já o desenho experimental 2 (PA-2) corresponde a um sistema de captação e tratamento de água em uma propriedade rural localizada em Vera Cruz, RS, entre setembro de 2013 e fevereiro de 2014. Os resultados para o PA-1 indicaram que o efluente bruto apresentou uma CE (I)50% 48h de 51,3 ± 17,2%, correspondendo a uma amostra medianamente tóxica. Nos pontos P2, P3, P4 e P5 as amostras apresentaram-se pouco tóxicas. Para o PA-2, os resultados indicaram que o efluente bruto apresentou uma CE (I)50% 48h de 8,1 ± 2,6%, correspondendo a uma amostra extremamente tóxica. Nos pontos P2 e P3 as amostras enquadraram-se como altamente e pouco tóxicas, respectivamente. No P4 os efluentes não apresentaram toxicidade. Do ponto de vista da ecotoxicologia, os resultados sugerem que o uso de H. grumosa como componente principal nos WC’s foi significativa, representando uma alternativa promissora para remover toxicidade de efluentes domésticos

MÉTODOS PARA A REMOÇÃO DE SULFETO DE HIDROGÊNIO DE EFLUENTES GASOSOS APLICÁVEIS A REATORES ANAERÓBIOS

Neste trabalho de revisão foram avaliados os principais métodos utilizados para o tratamento de emissões atmosféricas contendo H2S, descrevendo suas vantagens e desvantagens. Buscou-se encontrar tecnologias mais adequadas para o tratamento do H2S emitido por reatores anaeróbios. Uma análise qualitativa dos vários métodos indicou que a utilização de absorção química com solução redox de ferro (III) reúne o maior conjunto de vantagens para o tratamento do H2S emitido por este tipo de reatores, como a possibilidade da reutilização da solução de ferro evitando gastos com reposição de reagentes e geração de um coproduto (enxofre elementar) que pode ser comercializado ou retornado ao meio ambiente em forma de insumos agrícolas

Proposta de implantação de P+L em um frigorífico de suínos de grande porte

Customarily awareness by companies occurs through the need to service a new audience, called "green consumer", which requires knowledge about the origin of the products they consume and also require that the production conforms to environmentally sound practices, or by means of coercive factors such as fines and penalties due to possible impacts on the environment. This study evaluated the critical points in the production process of a large pig fridge, using the tools of Environmental Impact Assessment (EIA), the Failure Mode and Effect Analysis (FMEA) and Severity Urgency and Trend (GUT). It was observed that the comparison between the headquarters FMEA and GUT pointed to the high water consumption as the main critical point, especially in the premises cleaning process. The implementation of an Environmental Management System and the adoption of Cleaner Production measures contributed positively to the reduction in water consumption and meant a reduction in the company's production costs, bringing guidelines for proper waste management, awareness for the rational use of water and adding value to the waste generated.Costumeiramente a conscientização por parte das empresas ocorre por meio da necessidade de atendimento de um novo público, denominado “consumidor verde”, que exige o conhecimento sobre a procedência dos produtos que consomem e também exigem que a produção esteja de acordo com praticas ambientalmente corretas, ou ainda por meio de fatores coercitivos como multas e sanções em função de possíveis impactos gerados sobre o meio ambiente. O presente trabalho avaliou os pontos críticos do processo produtivo de um frigorífico de suínos de grande porte, utilizando as ferramentas Avaliação de Impacto Ambiental (AIA), Análise dos Modos de Falhas e seus Efeitos (FMEA) e Gravidade Urgência e Tendência (GUT). Foi possível observar que o comparativo entre as matrizes FMEA e GUT apontaram o elevado consumo de água como ponto crítico principal, principalmente no processo de limpeza das instalações. A implantação de um Sistema de Gestão Ambiental e a adoção de medidas de Produção mais Limpa contribuiu positivamente para a redução no consumo de água e significou a redução nos custos de produção da empresa, trazendo diretrizes para o correto gerenciamento dos resíduos, a conscientização para o uso racional da água e a agregação de valores aos resíduos gerados

Evaluation of the influence of glycerol in ceramic matrix

O presente trabalho avalia os efeitos da adição de glicerol sobre a porosidade e resistência mecânica de um material cerâmico. As amostras foram compactadas por prensagem uniaxial e submetidas a temperaturas de queima de 950 °C e 1100 °C, com taxa de aquecimento de 7 °C min-1 . Foram realizados ensaios físicos e mecânicos para analisar porosidade aparente, absorção de água, retração linear e resistência mecânica a flexão. Os resultados mostram que a adição de 10% de glicerol à argila melhora principalmente suas propriedades mecânicas, podendo ser um aditivo promissor para gerar materiais cerâmicos estruturais com microestrutura mais resistente.The present work evaluates the effects of the glycerol addition on the porosity and mechanical resistance of a ceramic material. Samples were compacted by uniaxial pressing and were submitted to different sintering temperatures, 950 °C and 1100° C, with a heating rate of 7 °C min-1 . Physical and mechanical analysis were performed to evaluate porosity, water absorption and linear retraction. The results show that the addition of 10% of glycerol into the clay mainly improves its mechanical properties, being able to be a promising additive to generate structural materials with more resistant microstructure

Link Between Sustainability and Industry 4.0: Trends, Challenges and New Perspectives

The increasing number of studies that underline the relationship between industry 4.0 and sustainability shows that sustainability is one of the pillars of smart factories. Through a bibliometric performance and network analysis (BPNA), this research describes the existing relationship between industry 4.0 and sustainability, the strategic themes from 2010 to March 2019, as well as the research gaps for proposing future work. With this goal in mind, 894 documents and 5621 keywords were included for bibliometric analysis, which were treated with the support of Science Mapping Analysis Software Tool (SciMAT). The bibliometric performance analysis presented the number of publications over time and the most productive journals. The strategic diagram shown 12 main research clusters, which were measured according to bibliometric indicators. Moreover, the network structure of each cluster was depicted, and the patterns found were discussed based on the documents associated to the network. Our findings show the scientific efforts are focused to enhance economic and environmental aspects and highlights a lack of effort relating the social sphere. Finally, the paper concludes the challenges, perspectives, and suggestions for the potential future work in the field of study relating to industry 4.0 and sustainability

Floating treatment wetlands in domestic wastewater treatment as a decentralized sanitation alternative

Floating treatment wetlands (FTW) are technologies that have stood out for their efficiency, ease of installation and maintenance. They consist of macrophytes emerging in a floating structure that keep the plant roots in direct contact with the effluent regardless of the water flow variation over time, allowing the removal of pollutants by various processes. The application of FTWs for the treatment of domestic wastewater has the advantage of low costs in terms of removing nutrients and at the same time reducing the cost of maintenance and energy consumption when compared to the conventional centralized treatment of effluent. The lack of wastewater treatment in areas distant from urban centers is even more limited, mainly due to the high cost of tubing and pumps for the effluent to reach the treatment plants. Therefore, the objective of this study was to research FTW systems applied to the decentralized treatment of domestic wastewater. First, a bibliometric analysis was conducted comparing the main issues involving FTW, and the challenges regarding the integration of FTW and domestic wastewater treatment systems. The feasibility of the floating system as a decentralized treatment approach were discussed, as well as the removal of nutrients in domestic wastewater, which was the most covered topic by researchers who developed studies in the area. In addition, other technologies are being integrated into the phytoremediation systems seeking to improve the quality of the treated effluent and assessing the potential reuse in the homes where they are generated and treated, determining the costs and space requirements for the entire process. There is a large research gap regarding the treatment of domestic wastewater by FTW in decentralized systems, mainly in terms of operation, cost assessment and reuse Therefore, further investigations in order to better understand the performance of the process and the reactions that occur with physical, chemical and microbiological removal mechanisms are still necessary

Hybrid constructed wetlands integrated with microbial fuel cells and reactive bed filter for wastewater treatment and bioelectricity generation

The present study aimed to develop a pilot-scale integrated system composed of anaerobic biofilter (AF), a floating treatment wetland (FTW) unit, and a vertical flow constructed wetland coupled with a microbial fuel cell (CW-MFC) and a reactive bed filter (RBF) for simultaneously decentralized urban wastewater treatment and bioelectricity generation. The first treatment stage (AF) had 1450 L and two compartments: a settler and a second one filled with plastic conduits. The two CWs (1000 L each) were vegetated with mixed plant species, the first supported in a buoyant expanded polyethylene foam and the second (CW-MFC) filled with pebbles and gravel, whereas the RBF unit was filled with P adsorbent material (light expanded clay aggregate, or LECA) and sand. In the CW-MFC units, 4 pairs of electrode chambers were placed in different spacing. First, both cathode and anode electrodes were composed of graphite sticks and monitored as open circuit. Later, the cathode electrodes were replaced by granular activated carbon (GAC) and monitored as open and closed circuits. The combined system efficiently reduced COD (> 64.65%), BOD₅(81.95%), N-NH₃(93.17%), TP (86.93%), turbidity (94.3%), and total coliforms (removal of three log units). Concerning bioenergy, highest voltage values were obtained with GAC electrodes, reaching up to 557 mV (open circuit) and considerably lower voltage outputs with closed circuit (23.1 mV). Maximum power densities were obtained with 20 cm (0.325 mW/m²) and 30 cm (0.251 mW/m2). Besides the electrode superficial areas, the HRT and the water level may have influenced the voltage values, impacting DO and COD concentrations in the wastewater