ESTUDO EXPERIMENTAL E NUMÉRICO DO COMPORTAMENTO DO ÍON CÁLCIO EM SOLO DO ATERRO MUNICIPAL DE VOLTA REDONDA.

O presente trabalho consiste no estudo da previsão da dinâmica do íon cálcio através do solo do Aterro Municipal de Volta Redonda, situado no Estado do Rio de Janeiro. O estudo se baseia no movimento do líquido contaminante (solução) no meio poroso (solo), com a determinação da sua taxa de sorção. Para tanto, foram realizados ensaios em colunas de PVC, contendo solo do Aterro, onde ocorre o processo de transferência do íon cálcio entre a solução contaminante e o solo. Utilizaram-se como solução contaminante o lixiviado do Aterro e a solução de gesso agrícola. Foram realizados ensaios de laboratório para determinar parâmetros de interação do solo com o íon cálcio e simulações computacionais para prever o comportamento do transporte do íon após período de 5 dias. O modelo utilizado foi o MPHMTP (Multi Phase Heat and Mass Transfer Program) desenvolvido pelo programa de Pós-Graduação em Engenharia Metalúrgica de Volta Redonda (PPGM/EEIMVR/UFF). A simulação computacional determina numericamente os parâmetros de transporte no sistema solo-chorume. Os resultados obtidos durante a realização deste trabalho mostraram que a migração do cálcio pode ser explicada através da ação simultânea de três fenômenos, que são: difusão, sorção e advecção. Palavras-chave: difusão, sorção, mecanismos de transporte, lixiviado ABSTRACT Experimental and numerical study of the behavior of Calcium ion in the Volta Redonda municipal solid waste landfill. The present work aims to study the dynamics of calcium ion within the soil of Volta Redonda Municipal Solid Waste (MSW) landfill, located in Rio de Janeiro state, Brazil. The study is based on the movement of fluid contaminant (solution) into the porous matrix (soil) and determination of the sorption rate of calcium. The experimental procedure was carried out in PVC columns containing soil from the Landfill, with both, the leachate of the MSW and synthetic solutions with controlled concentrations of calcium ion. The experimental results were carried out for 5 days and the concentrations of the liquid were recorded. A computer software (MPHMTP), developed by the Graduate Program on Metallurgical Engineering of Volta Redonda (PPGM/EEIMVR/UFF) was used to determine the transport parameters and the ion concentration on liquid and solid for same conditions of the experiment. The computational simulation determines numerically the parameters of transport in the system soilleachate. Based on the experimental and numerical simulations carried out in this investigation, it is concluded that the migration of calcium can be explained by the simultaneous action of phenomena which are diffusion, advection in the liquid solution and sorption/desorption in the soil particles. Key words: diffusion, sorption, transport mechanisms, leachat

Simulação computacional e validação da migração de íons de chorume no solo através de um modelo baseado nos fenômenos de transferência de massa

Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorA técnica de aterros sanitários para disposição de resíduos sólidos é a mais difundida e aceita no Brasil. Os mecanismos de decomposição da matéria orgânica, a influência da composição no comportamento da massa de lixo, a eficiência na atenuação de sua carga contaminante, tipos de tratamento e os riscos ambientais são aspectos relevantes que não foram ainda completamente explorados. Neste trabalho, utiliza-se a técnica da simulação computacional aliada a experimentos direcionados, com o objetivo de se construir uma ferramenta de cálculo para análise dos impactos ambientais causados pela deposição de lixo urbano no Aterro Metropolitano de Gramacho, localizado na cidade de Duque de Caxias RJ. O desenvolvimento da pesquisa se deu através da construção do modelo para a simulação a partir de dados experimentais, com o objetivo de determinar parâmetros da cinética de transferência de íons do chorume para o solo, e vice-versa. Pesquisas anteriores enfatizaram os fenômenos de difusão e sorção através de modelos simples (Linear, Langmuir e Freundlich) no processo de migração de contaminantes do chorume para o solo. Neste trabalho, através da simulação computacional, foi possível verificar que o processo de migração de íons não pode ser explicado completamente como resultado de difusão iônica e sorção, mas sim através da ação simultânea de três fenômenos de transferência de massa: difusão, sorção e advecção

Effects of the silica nanoparticles (NPSiO2) on the stabilization and transport of hazardous nanoparticle suspensions into landfill soil columns

Abstract This study evaluates the stability and transport behaviors of hazardous nanoparticles into soil landfills using experimental procedures to simulate the effects of natural silica nanoparticle suspensions during their percolation into the soil layers of municipal waste landfills. For this, we prepared stabilized suspensions of nanoparticle oxides containing silicon (NPSiO2), titanium (NPTiO2), copper (NPCuO) and zinc (NPZnO), which are recognized as hazardous to the environment, and we conducted leaching experiments within the soil column by simulating landfills layers and simulating the capture and attenuation of nanomaterials into municipal waste landfills. The results demonstrated that the presence of NPSiO2 in suspensions increases the stable concentrations of copper, zinc and titanium oxides and strongly decreases soil layer effectiveness. In contrast, NPZnO improves effectiveness due to its ability to promote agglomeration and setting conditions, allowing further complexation

Brazilian Flora 2020: Leveraging the power of a collaborative scientific network

International audienceThe shortage of reliable primary taxonomic data limits the description of biological taxa and the understanding of biodiversity patterns and processes, complicating biogeographical, ecological, and evolutionary studies. This deficit creates a significant taxonomic impediment to biodiversity research and conservation planning. The taxonomic impediment and the biodiversity crisis are widely recognized, highlighting the urgent need for reliable taxonomic data. Over the past decade, numerous countries worldwide have devoted considerable effort to Target 1 of the Global Strategy for Plant Conservation (GSPC), which called for the preparation of a working list of all known plant species by 2010 and an online world Flora by 2020. Brazil is a megadiverse country, home to more of the world's known plant species than any other country. Despite that, Flora Brasiliensis, concluded in 1906, was the last comprehensive treatment of the Brazilian flora. The lack of accurate estimates of the number of species of algae, fungi, and plants occurring in Brazil contributes to the prevailing taxonomic impediment and delays progress towards the GSPC targets. Over the past 12 years, a legion of taxonomists motivated to meet Target 1 of the GSPC, worked together to gather and integrate knowledge on the algal, plant, and fungal diversity of Brazil. Overall, a team of about 980 taxonomists joined efforts in a highly collaborative project that used cybertaxonomy to prepare an updated Flora of Brazil, showing the power of scientific collaboration to reach ambitious goals. This paper presents an overview of the Brazilian Flora 2020 and provides taxonomic and spatial updates on the algae, fungi, and plants found in one of the world's most biodiverse countries. We further identify collection gaps and summarize future goals that extend beyond 2020. Our results show that Brazil is home to 46,975 native species of algae, fungi, and plants, of which 19,669 are endemic to the country. The data compiled to date suggests that the Atlantic Rainforest might be the most diverse Brazilian domain for all plant groups except gymnosperms, which are most diverse in the Amazon. However, scientific knowledge of Brazilian diversity is still unequally distributed, with the Atlantic Rainforest and the Cerrado being the most intensively sampled and studied biomes in the country. In times of “scientific reductionism”, with botanical and mycological sciences suffering pervasive depreciation in recent decades, the first online Flora of Brazil 2020 significantly enhanced the quality and quantity of taxonomic data available for algae, fungi, and plants from Brazil. This project also made all the information freely available online, providing a firm foundation for future research and for the management, conservation, and sustainable use of the Brazilian funga and flora

Growing knowledge: an overview of Seed Plant diversity in Brazil

Abstract An updated inventory of Brazilian seed plants is presented and offers important insights into the country's biodiversity. This work started in 2010, with the publication of the Plants and Fungi Catalogue, and has been updated since by more than 430 specialists working online. Brazil is home to 32,086 native Angiosperms and 23 native Gymnosperms, showing an increase of 3% in its species richness in relation to 2010. The Amazon Rainforest is the richest Brazilian biome for Gymnosperms, while the Atlantic Rainforest is the richest one for Angiosperms. There was a considerable increment in the number of species and endemism rates for biomes, except for the Amazon that showed a decrease of 2.5% of recorded endemics. However, well over half of Brazillian seed plant species (57.4%) is endemic to this territory. The proportion of life-forms varies among different biomes: trees are more expressive in the Amazon and Atlantic Rainforest biomes while herbs predominate in the Pampa, and lianas are more expressive in the Amazon, Atlantic Rainforest, and Pantanal. This compilation serves not only to quantify Brazilian biodiversity, but also to highlight areas where there information is lacking and to provide a framework for the challenge faced in conserving Brazil's unique and diverse flora