Evaluation of microplastic contamination by metals in a controlled environment: A risk to be considered.

The metal contamination and the degradation of polyethylene terephthalate (PET) due to human activities have contributed to the worsening of environmental problems in aquatic systems. Therefore, the study aimed to evaluate PET microplastic adsorption levels when exposed to high amounts of Ni, Cu and Co. The PET microplastic was characterized by scanning electron microscopy, Brunner-Emmet-Teller, porosimetry system, Barrett-Joyner-Halenda and Fourier transform infrared spectroscopy with attenuated total reflectance for evaluation of surface morphology, surface area, porosity, pore size and functional groups, respectively. The results showed that the surface area, the presence of macro and mesopores, and the functional groups influence the adsorption of metals on the surface of PET microplastic. The adsorption isotherms confirmed the presence of mesoporosity and macroporosity on the PET microplastic surface. The Freundlich and Langmuir models were used to study the adsorption capacity. The kinetics of adsorptions were interpreted using pseudo-first order and pseudo-second order models. The results indicated that the Langmuir isotherm and the pseudo-second order adequately described the adsorption of metals by the PET microplastic. The removal rates by the PET microplastic varied from 8 to 34% for Ni, 5 to 40% for Cu and 7 to 27% for Co after a period of 5 days. Furthermore, the adsorption was predominantly chemical and extremely fast, indicating that the presence of microplastics in the environment can lead to a rapid metal accumulation which elevates the hazards potential of microplastic in living beings.

Challenges of selective collection of the household waste: A case study in a Brazilian metropolis.

This work sought to analyse the main difficulties in implementing and maintaining the selective waste collection in a Brazilian metropolis with more than one million inhabitants. Therefore, a qualitative method was used through in-depth interviews with 18 professionals working in the area of selective collection. The interviews were recorded and the data submitted to content analysis. The results showed the following difficulties: lack of management by the government, low efficiency and limited coverage; poor separation of waste at source; distortions in the selective collection logistics chain and in the distribution of waste by cooperatives; high informality, precarious work and low pay for waste collectors; the presence of middlemen and corruption in the system; and idle capacity of cooperatives and public organs. It was concluded that to overcome the difficulties in the selective collection and for it to be more effective, there is a need to improve the management of the process by the government with greater transparency and integration between the various actors involved, education of the population, better working conditions and remuneration for waste collectors.

An electrochemical sensor-based carbon black associated with a modified mixed oxide (SiO2/TiO2/Sb2O5) for direct determination of thiamethoxam in raw honey and water samples.

The study aimed to develop an electrochemical sensor based on glassy carbon, mixed oxide (SiO2/TiO2/Sb2O5), and carbon black. The material was synthesized, characterized, and used to determine thiamethoxam in raw honey and water. The morphologic structure and electrochemical performance of the sensor was characterized by scanning electron microscopy and cyclic voltammetry. Differential pulse voltammetry with a concentration of 0.1 mol L-1 of Britton-Robinson buffer at pH 7.0 allowed the generation of a method to determine thiamethoxam in a linear range of 0.25 to 100.5 µmol L-1 and with a limit of detection of 0.012 µmol L-1. The system efficiently quantified traces of thiamethoxam in raw honey and tap water samples. The modified sensor did not present interferences of K+, Na+, Ca2+, Mg2+, glyphosate, imidacloprid, and carbendazim. In addition, the device showed good recovery values for thiamethoxam when applied directly to honey and water samples without any treatment, presenting an electrochemical sensor to monitor real-time hazardous substances in environmental and food matrices.

Treatment of a slaughterhouse wastewater by anoxic-aerobic biological reactors followed by UV-C disinfection and microalgae bioremediation.

In this study, removal of organic matter and nitrogen from a cattle slaughterhouse wastewater was investigated in a two-stage anoxic-aerobic biological system, followed by UV-C disinfection. Ecotoxicity of the raw, biotreated, and disinfected wastewater against the microalgae Scenedesmus sp. was evaluated in short-term tests, while the potential of the microalgae as a nutrient removal step was addressed in long-term experiments. Throughout 5 operational phases, the biological system was subjected to gradual reduction of the hydraulic retention time (8-1.5 day), increasing the organic (0.21-1.11 kgCOD·m-3 ·day-1 ) and nitrogen (0.05-0.28 kgN·m-3 · day-1 ) loading rates. COD and total ammoniacal nitrogen (TAN) removal ranged within 83%-97% and 83%-99%, respectively. While providing alkalinity source, effluent TAN concentrations were below 5 mg·L-1 . Nitrate was the main nitrification product, while nitrite levels remained low (<1 mgN·L-1 ). Upon supplementation of external COD as ethanol, total nitrogen removal reached up to 90% at the highest load (0.28 kgN·m-3 ·day-1 ). After UV-C treatment, 3-log reduction of total coliforms was attained. The 96-hr ecotoxicity tests showed that all non-diluted samples tested (raw, biologically treated and UV-C irradiated wastewater) were toxic to microalgae. Nevertheless, these organisms were able to acclimate and grow under the imposed conditions, allowing to achieve nitrogen and phosphorous removal up to 99.1% and 43.0%, respectively. PRACTITIONER POINTS: The treatment of a slaughterhouse wastewater in an anoxic-aerobic biological system followed by a UV-C disinfection step was assessed. The pre-denitrification system showed efficient simultaneous removal of organic matter and nitrogen from the wastewater under increasing applied loads. UV-C disinfection worked effectively in reducing coliforms from the biotreated effluent, boosting the performance of microalgae on nutrients removal. Despite the toxicity to microalgae, they were capable to acclimate to the aqueous matrices tested, reducing efficiently the nutrients content. The combined stages of treatment presented great capacity for depleting up to 97% COD, 99% nitrogen, and 43% phosphorous.

Tratamento de lixiviado por processos combinados: coagulação/floculação, air stripping, ozonização e lodo ativado / Leachate treatment by combined processes: coagulation/flocculation, air stripping, ozonation and activated sludge

RESUMO Os lixiviados de áreas de disposição de resíduos municipais apresentam, em geral, alta complexidade, variabilidade, toxicidade, recalcitrância e alta concentração de nitrogênio amoniacal. Neste estudo, aplicaram-se técnicas combinadas para o tratamento de um lixiviado, a saber: coagulação/floculação (C/F), air stripping e ozonização, combinados com o tratamento por lodo ativado com/sem inserção de carvão ativado. O processo de C/F levou a uma redução na demanda química de oxigênio (DQO) de 58,1% e na cor, de 85,6%. O air stripping foi realizado em pH>12 e obteve-se diminuição dos níveis de nitrogênio amoniacal para abaixo de 60 mg.L-1. O processo de ozonização, com consumo de ozônio de 397 mgO3.L-1 e 2.376 mgO3.L-1, apresentou bons resultados, com aumento de 59,4% na relação DBO5/DQO e uma redução de toxicidade superior a 85%. Obteve-se melhor eficiência para o lodo ativado sem carvão ativado, com lixiviado pré-tratado por C/F + air stripping + ozonização (400 mgO3.L-1). Tal combinação resultou em uma redução de 90,6% na DQO do lixiviado e mais de 99% nos níveis de nitrogênio amoniacal.

ABSTRACT Leachate from waste disposal areas generally presents high complexity, variability, toxicity, recalcitrance and high concentration of ammonia nitrogen. In this work, combined techniques for the treatment of leachate were applied, namely: coagulation/flocculation, air stripping and ozonation combined with activated sludge treatment with/without activated carbon. The coagulation/flocculation process led to a COD reduction of 58.1% and color removal of 85.6%. The air stripping was performed at pH>12 and reduced ammonia levels below of 60 mg.L-1. The ozonation process (ozone consumption of 397 mgO3.L-1 and 2376 mgO3.L-1) presented good results. It was observed a BOD5/COD increase of 59.4% and a toxicity reduction of more than 85%. The best efficiency was observed with sludge activated without activated carbon for the pre-treated leachate by coagulation/flocculation + air stripping + ozonation (400 mgO3.L-1). This combination resulted in a COD reduction of 90.6% and more than 99% of ammonia nitrogen removal.

Avaliação de novas práticas de compostagem em pequena escala com aproveitamento energético / Evaluation of new composting practices in small-scale with energy recovery

RESUMO: Foram avaliados neste estudo novos sistemas de compostagem de mínimo impacto ambiental para o tratamento in loco de resíduos orgânicos. Dois tipos de composteiras e quatro formas de manejo foram testados. Focaram-se ainda duas composições de resíduos sólidos orgânicos com relação ao aproveitamento energético por aquecimento de água. Os resíduos mantiveram temperaturas termofílicas por mais de 20 dias, apresentaram produção desprezível de metano e não geraram chorume em condições de aeração passiva. Como aspectos de maior influência, podem ser considerados: a suspensão das composteiras sobre pallets, a composição dos resíduos, as condições de contorno das composteiras e o manejo adotado. No teste de recuperação energética, temperaturas de até 51ºC foram alcançadas após 24 horas de circulação de água no sistema, sugerindo que o processo pode ser uma fonte potencial de economia de energia. O modelo de compostagem proposto é ambientalmente adequado, porque minimiza emissões e geração de lixiviado se comparado a aterros sanitários e plantas de compostagem industrial, sendo indicado para cozinhas industriais, condomínios, shopping centers e outros geradores em pequena e média escalas.

ABSTRACT: This study comprehends the research of new composting systems for the organic solid waste treatment with low environmental impact. Two types of composting, four types of management and its economic feasibility were tested, as well as two compositions of organic solid waste focused at energy recovery by heating water. The composting maintained the thermophilic process for more than 20 days, showed a non-significant CH4 emission, maintained aerobic conditions by passive aeration, without leachate generation. The aspects with increase influence were: suspension of composters on pallets, waste composition, condition of composters, and adopted management. The test of energetic recovery showed that the water reached temperatures up to 51ºC after 24 hours of recirculation, demonstrating that this process can be a potential energy source. The proposed composting model is environmental feasible, because it minimizes gas emission and leachate generation compared to the landfill or industrial composting plants. Therefore, it is suggested to be used in industrial kitchens, condos, shopping malls, and other small and medium generators.

Respiratory diseases of children living near a dumpsite / Doenças respiratórias de população infantil residente próxima a lixão

Despite recognition of the socioenvironmental impacts of improper manangement and disposal of municipal solid waste (MSW), often involiving diseases, few studies have been carried out to investigate the association between this waste management and health. It is important to know the health status of people living near landfills and dumps, to make those responsible for managment aware of the need to establish more effective sanitation policies. For this purpose, we conducted a descriptive case study with primary data on repiratory diseases of children living near a trash dump. The field work was performed in two periods in 2005 and 2016. In the first, the dump was in operation, while in the second it had been shut down for about five years. The study was conducted in a city in the state of Rio de Janeiro with a population of about 47,000 people in 2006. The results indicate that the rates of respiratory diseases among children living in the area surrounding the dump were higher in 2005 than in 2016, a finding that might be related to the dump's closure. In ten cases the decline in the ailments reported by the respondents was significant, led by wheezing attacks after exercise (26.4 percengage points lower) and pneumonia (16 p.p.lower). In six cases, the rates were slightly higher, suggesting the need for a more thorough study to investigate this increase. The results are not definitive, but indicate the importance of the considering the negative health effects of trash dumps and the need to close them or improve the treatment and disposal of municipal solid waste.

Apesar de reconhecidos os impactos socioambientais causados pelo manejo e disposição irregulares dos resíduos sólidos urbanos (RSU), muitas vezes relacionados à incidência de doenças, poucos estudos têm sido realizados com o intuito de verificar a associação entre os efeitos do seu gerenciamento inadequado e a saúde. É importante conhecer o estado de saúde da população residente nas proximidades de aterros de RSU visando conscientizar os responsáveis pelo seu gerenciamento sobre a necessidade de estabelecer políticas mais efetivas nos programas de saneamento dos Estados. Para isso, foi feito um estudo de caso descritivo e quantitativo com dados primários sobre doenças respiratórias de crianças residentes no entorno de um lixão. As pesquisas de campo foram feitas em duas épocas distintas: em 2005 e 2016. Na primeira pesquisa o lixão se encontrava em operação, enquanto que na segunda pesquisa, estava desativado há cerca de cinco anos. O estudo foi desenvolvido numa cidade do Estado do Rio de Janeiro com população aproximada de 47.000 habitantes em 2006. Os resultados dão conta de que as doenças do trato respiratório em crianças residentes próximas ao aterro estudado apresentam índices mais elavados, na primeira, com declínio, na segunda pesquisa, e que este fato pode estar relacionado com o fechamento do lixão. Em dez casos o declinio das doenças relatadas pelos sujeitos da pesquisa é significativo, como por exemplo, assovio ou chiado no peito (de 26.4% menor) e pneumonia (16% menor). Em outros 6 casos os índices são levemente mais elevados, sugerindo a necessida de realização de um estudo mais profundo de modo a investigar este aumento. Os resultados não são definitivos, mas indicam a importância de fechamento dos lixões, seus possíveis efeitos negativos à saúde e melhores tratamentos e disposições de residuos solidos urbanos.

Analytical study of the performance of a geomembrane leak detection system.

The electrical detection of leaks in geomembranes is a method that allows identifying leakage of contaminants in lined facilities (e.g. sanitary landfills, pollutant ponds, etc.). The procedure in the field involves placing electrodes above and below the geomembrane, to generate an electrical current, which in turn engenders an electric potential distribution in the protective layer (generally a clayey soil). The electric potential will be greater in areas with higher current density, i.e. near leaks. In this study, we combined models from the literature to carry out a parametric analysis to identify the variables that most influence the amplitude of the electrical signals produced by leaks. The basic hypothesis is that the electrical conduction phenomena in a liner system could be depicted by a direct current circuit. After determining the value of the current at the leak, we calculated the electric potential distribution according to the model of Darilek and Laine. This enabled analysing the sensitivity of the parameters, which can be useful in the design of landfills and facilitate the location of leaks. This study showed that geomembranes with low electrical resistance (owing to low thickness, low resistivity, or extensive area) can hinder the leak detection process. In contrast, low thickness and high resistivity of the protection layer magnify the leak signal.

A soil-plant model applied to phytoremediation of metals.

This study reports a phytoremediation pot experiment using an open-source program. Unsaturated water flow was described by the Richards' equation and solute transport by the advection-dispersion equation. Sink terms in the governing flow and transport equations accounted for root water and solute uptake, respectively. Experimental data were related to application of Vetiver grass to soil contaminated by metal ions. Sensitivity analysis revealed that due to the specific experimental set-up (bottom flux not allowed), hydraulic model parameters did not influence root water (and contaminant) uptake. In contrast, the results were highly correlated with plant solar radiation interception efficiency (leaf area index). The amounts of metals accumulated in the plant tissue were compared to numerical values of cumulative uptake. Pb(2+) and Zn(2+) uptake was satisfactorily described using a passive model. However, for Ni(2+) and Cd(2+), a specific calibration of the active uptake model was necessary. Calibrated MM parameters for Ni(2+), Cd(2+), and Pb(2+) were compared to values in the literature, generally suggesting lower rates and saturation advance. A parameter (saturation ratio) was introduced to assess the efficiency of contaminant uptake. Numerical analysis, applying actual field conditions, showed the limitation of the active model for being independent of the transpiration rate.

Phytoremediation of metals: a numerical analysis.

A finite element code was used for investigating the effect of some relevant characteristics of a phytoremediation project (crop type and density, presence of an irrigation system, soil capping and root depth). The evolution of the plume of contamination of Cd2+, Pb2+, and Zn2+ was simulated taking into account reactive transport and root processes. The plant contaminant uptake model was previously calibrated using data from greenhouse experiments. The simulations adopted pedological and climatological data representative of a sub-tropical environment. Although the results obtained were specific for the proposed scenario, it was observed that, for more mobile contaminants, poor water conditions favor stabilization but inhibit plant extraction. Otherwise an irrigation system that decreases crop water stress had an opposite effect. For less mobile contaminants, the remediation process did not have appreciable advantages. Despite its simplifying assumptions, particularly about contaminant sorption in the soil and plant system, the numerical analysis provided useful insight for the phytoextraction process important in view of field experiments.

Barreira capilar construida com residuo pre-tratado mecanica e biologicamente / Capillary barrier constructed with mechanical biological treatment waste

O controle da entrada de água de chuva no interior do aterro de resíduos sólidos urbanos durante sua construção e após seu fechamento é crucial para manter o controle da geração de lixiviado. Este fator pode contribuir para a elevação de gastos com tratamento e monitoramento e para a instabilidade mecânica do aterro. Por esta razão, o sistema de cobertura final de um aterro de resíduos sólidos urbanos é decisivo ao controle da entrada de água no mesmo. Na maioria dos casos, o sistema de cobertura final é composto por solo compactado. Frequentemente, um solo adequado para a cobertura não é encontrado nos arredores do aterro; portanto, recursos têm que ser despendidos para o transporte do mesmo até o devido local. Uma alternativa seria a utilização de uma barreira capilar construída com resíduos pré-tratados mecânica e biologicamente. No entanto, o uso deste material para esta construção ainda não foi bem estudado, e as diversas variáveis envolvidas no funcionamento de uma barreira capilar construída com resíduos sólidos pré-tratados mecânica e biologicamente são desconhecidas. O objetivo deste trabalho foi analisar os parâmetros envolvidos no funcionamento de uma barreira capilar construída exclusivamente de resíduos sólidos urbanos pré-tratados mecânica e biologicamente. Observou-se que este utilizado como material de uma barreira capilar pode funcionar de maneira equivalente àquela construída com solo, sendo boa a sua capacidade de retenção da água de chuva.

The control of rainwater entry into the municipal solid waste landfill during its construction and after its closure is crucial to keep track of leachate generation. This is a factor that may contribute to the increase of costs on treatment and monitoring and to the mechanical instability of the landfill. For this reason, the final cover system of a municipal solid waste landfill is critical for controling the water entering into the landfill. In most cases, the final cover system is made of compacted soil. Often, suitable soil for landfilling is not found in its surroundings, and resources must be expended in transporting the soil to the landfill site. An alternative would be to use a capillary barrier constructed with mechanical and biologically pretreated waste. However, the use of this material to construct capillary barriers has not been studied and several variables involved in the operation of a capillary barrier constructed with municipal solid mechanical and biologically pretreated waste landfill are unknown. The objective of this study was to analyze the parameters involved in the operation of a capillary barrier built exclusively solid waste pre-treated mechanically and biologically. It was observed that the MSW MBT used as a capillary barrier material may function similarly to that constructed with soil, with a good capacity for rain water retention.

A model for estimation of potential generation of waste electrical and electronic equipment in Brazil.

Sales of electrical and electronic equipment are increasing dramatically in developing countries. Usually, there are no reliable data about quantities of the waste generated. A new law for solid waste management was enacted in Brazil in 2010, and the infrastructure to treat this waste must be planned, considering the volumes of the different types of electrical and electronic equipment generated. This paper reviews the literature regarding estimation of waste electrical and electronic equipment (WEEE), focusing on developing countries, particularly in Latin America. It briefly describes the current WEEE system in Brazil and presents an updated estimate of generation of WEEE. Considering the limited available data in Brazil, a model for WEEE generation estimation is proposed in which different methods are used for mature and non-mature market products. The results showed that the most important variable is the equipment lifetime, which requires a thorough understanding of consumer behavior to estimate. Since Brazil is a rapidly expanding market, the "boom" in waste generation is still to come. In the near future, better data will provide more reliable estimation of waste generation and a clearer interpretation of the lifetime variable throughout the years.

Sistema de avaliação para classificar áreas de disposição de resíduos sólidos urbanos visando a remediação e a pós-ocupação / Evaluation system for rating urban solid waste disposal sites for remediation and post occupation

A disposição de resíduos sólidos urbanos em locais sem infra-estrutura de proteção ambiental pode ser responsável pela contaminação de recursos naturais e de seres humanos e animais por meio da emissão de efluentes líquidos e gasosos. A metodologia proposta visa contribuir com a avaliação do risco de exposição ao lixiviado, bem como sugerir procedimentos de monitoramento da área, de acordo com diferentes níveis de cuidado e urgência. O método baseia-se em quatro matrizes onde é possível ser feita uma avaliação inicial da fonte do risco, do sujeito potencialmente atingido, e dos caminhos ambientais superficiais e subterrâneos. Neste trabalho foi considerada, essencialmente, a contaminação causada por efluentes líquidos.

Disposal of urban solid waste in sites without infrastructure for environmental protection may be responsible for contamination of natural resources and human beings by gas and liquid effluent emission. The proposed methodology aims to contribute in the evaluation of risk to the exposure to leachate as well as suggested procedures for site monitoring, according to different levels of care and urgency. The method is based on four matrices where it is possible to make an initial evaluation of the source of the risk, the potential target and the superficial and underground environmental paths. In this paper only the contamination caused by liquid effluents were considered.

Avaliação de aspectos de saúde e geo ambientais de aterros de resíduos sólidos / Evaluation of health, environmental and geographyca aspects of solid waste landfills

Este trabalho visou contribuir com o estudo de Aterros de Resíduos Sólidos no que se refere aos seus efeitos ambientais e à saúde da população que vive em suas proximidades. O aterro de um município próximo à cidade do Rio de Janeiro, com uma população de aproximadamente 40.000 habitantes foi escolhido como caso de pesquisa. O mesmo foi extensamente instrumentado para análise da sua dinâmica hídrica e de gases, tendo sido observado por um período de aproximadamente dois anos nos seus aspectos geo-hidrológicos e ambientais. Diversas análises químicas e físico-químicas de amostras das águas superficiais e subterrâneas, além de análise do solo e de gases foram realizados, assim como medições do nível freático e ensaios de campo que contribuíssem com o conhecimento da dinâmica ambiental do caso em estudo e servissem de referência no uso de procedimento de avaliação e projeto de tais aterros.Seus efeitos na saúde da população infantil foram também investigados fazendo aplicação de um questionário a uma população de 80 crianças que vivem e/ou estudam na proximidade do aterro. Utilizando-se o programa Hydrological Evaluation of Landfill Perfomance (H.E.L.P), estimou-se o volume de percolado produzido, e foi desenvolvido um modelo conceitual da dinâmica hídrica do aterro. A partir deste modelo quantificou-se o percentual da precipitação pluviométrica que atinge o aqüífero como lixiviado, a parte que permanece retida na massa de resíduos, e a parte que escoa superficialmente, em períodos do ano com diferentes características de balanço hídrico. Dentro de suas limitações como modelo o HELP mostrou ser uma ferramenta numérica interessante na previsão da produção de lixiviado em aterros de resíduos sólidos. Os procedimentos propostos para medidas de gás mostraram-se de grande valia, apesar das dificuldades encontradas no campo devido aos procedimentos de operação da execução da camada de cobertura. Previsões da produção de gás deste aterro foram feitas fazendo uso de doi...

Seminário Contribuição da Reciclagem de Entulho da Construção Civil à Saúde Ambiental no Estado do Rio de Janeiro - Claudio Mahler

O Prof. Claudio citou dados de pesquisas já realizadas e mostrou índices de qualidade no sistema de gestão ambiental em aterros de resíduos sólidos urbanos. Arquivo disponível para leitura, audição e/ou downlod nos ícones ao lado.