Premises for eco-efficiency analysis on construction and demolition waste recycling

The construction industry is associated with significative impacts such a consumption of natural resources and waste generation. Eco-efficiency is an instrument for sustainable analysis which indicates the relation between environmental costs and impacts. While the most environmental method used is the lifecycle assessment (LCA), standardized by ISO 14040, the economic indicator should be selected according to the stakeholder. Total cost, Unit Cost, Net Present Value (NPV) and Internal Rate of Return (IRR) are some of the economic indicators used in the economic analysis of Construction and Demolition Waste (CDW) recycling, however, the search for literature regarding the Eco-efficiency analysis shows a tendency to use the total cost regardless of its objective. In this sense, the objective of this paper is to propose the main premises to be considered in the selection of the economic indicator and in the normalization of the analysis of the CDW recycling Eco-efficiency index results. The search method adopted was comprised for three steps: Systematic review of literature; Analysis and comparison of Eco-efficiency indicators (including economic and environmental inputs); Discussion about the main assumptions in the CDW recycling Eco-efficiency analysis. 14 articles were identified in the Science Direct and Springer platforms. This paper provides information to propose premises to the Eco-efficiency analysis on CDW recycling. As a result, was defined a standard Eco-efficiency analysis according the objective: assessment of the cost to minimizing impacts, a simple comparison between scenarios or economic and environmental viability. The first two objectives refer to the input data variation and the scenarios evaluated, respectively. The third objective needs to compare the results with the current scenario, the final disposal and established market material that recycled aggregate can replace. Using the simplified flowchart proposed for each CDW recycling Eco-efficiency analysis objective will allow to standardize studies of this aspect, thus enabling more credible, replicable and comparable development

Avaliação do potencial de uso de resíduos de construção e demolição como componente para a recuperação de áreas degradadas por mineração

The evolution of modern civilization brings with it a series of challenges regarding the management of its waste. Proper disposal of construction and demolition waste (CDW) has become a challenge across the planet. Parallel to this challenge, there is another, that of recovering areas degraded by mining. The objective of the present work was to characterize through X-ray fluorescence (XRF),and X-ray diffraction (XRD) samples of CDW collected during the period from October 2018 to October 2019 in a recycling plant and to determine its potential as an element in the production of soils in the recovery of areas degraded by mining. Calcite and quartz were found in the CDW samples, as well as trace elements such as Fe, Mg, Mn, Cu, Zn, Ni, essential elements for plantnutrition, capable of restoring the chemical and physical conditions of soils. The results obtained showed that Chromium (Cr) and Barium (Ba) elements were found above the limits of CONAMA Resolution 420/2009 (Brazil). A comparison was made with Orden AAA/661/2013 (Spain), which guides the disposal of CDW in mining areas as a form of final disposal and mine closure.The presence of heavy metals is considered normal in Brazilian soils, some being considered essential micronutrients. The results provide datato affirmthat the CDWs can be used in soil production to recover areas degraded by mining, through the application of tests on a larger scale and with a soil-water-plant interface.A evolução da civilização moderna traz consigo uma série de desafios quanto à gestão de seus resíduos. A destinação adequada de resíduos de construção e demolição (RCD) tem se tornado um desafio em todo o planeta. Paralelo a este desafio, surge outro, o de recuperar áreas degradadas por mineração. O objetivo do presente trabalho foi caracterizar através de Fluorescência de raios X (FRX) e difração de raios X (DRX) amostras de RCD coletados durante período de outubro de 2018 a outubro 2019 em uma central de reciclagem e determinar seu potencial como elemento na produção de solos em recuperação de áreas degradadas por mineração. Foram encontrados calcita e quartzo nas amostras de RCD, além de elementos traço como Fe, Mg, Mn, Cu, Zn, Ni, elementos essenciais para anutrição vegetal, capazes de restaurar as condições químicas e físicas dos solos. Os resultados obtidos demonstraram que elementos Cromo (Cr) e Bário (Ba) encontraram-se acima dos limites da Resolução CONAMA 420/2009 (Brasil). Foi efetuada a comparação deparâmetros com aOrden AAA/661/2013(Espanha),a qual orienta a destinação de RCD em áreas de mineração como forma de destinação final e fechamento de minas.A presença de metais pesados é considerada normal em solos brasileiros, sendo alguns consideradosmicronutrientes essenciais. Os resultados fornecem dados para afirmar que os RCD são passíveis de utilização em produção de solos para fins de recuperação de áreas degradadas por mineração, mediante aplicação de testes em maior escala e com interface solo-água-planta

Life Cycle Assessment applied to construction and demolition waste treatment : proposal of a Brazilian scenario

Important amounts of construction and demolition wastes (CDW) are currently generated in several countries. Considering the correct management of this kind of residue, and the search for its noblest use, several studies have focused on the environmental potential impacts from CDW management. Life Cycle Assessment (LCA) is often used to investigate the potential environmental impacts over the life cycle of a product, thus becoming an important tool to support decision-making. CDW recycling process produces coarse, fine and mix aggregate as outputs, characterizing a multifunctional process. But, how CDW’s LCA should be run, considering a circular and more sustainable built environment? Thus, the objective of this work is to explore the basic premises in proposing a product system for the CDW recycling process in Brazil. For this, data available in the literature on the recycling process in Brazil and in other countries support the definition of the product system. The complexity of this management option is explored, considering how the use of the recycled materials interfere in the scope, objective, unit function and other modelling choices, as well as reliability of CDW studies. Finally, the datasets provided by Ecoinvent are examined in order to promote debate on data adaptation, followed by remarks on the most appropriate choices on allocation in the CDW LCA. The cut-off system modelling associated with the new perspective on the avoided burden approach is concluded by the authors to be the most suitable for this waste recycling multifunctional processes. Understanding system models is key. When no inventory adaptation is intended, available inventory datasets are more advisable to be used when performing end of life scenarios only, once burdens differ according to countries management scenarios, as well as life cycle inventory approaches

Integrated use of sewage sludge and basalt mine waste as soil substitute for environmental restoration

If not managed properly, mining waste can be detrimental to the environment. In addition, sewage treatment plants produce sludge, a biowaste rich in organic matter which is often sent to landfills. The present study evaluated the use of sewage sludge as an amendment for mine waste from a basalt quarry as an alternative to the use of soil from borrow areas during environmental restoration. An ex situ experiment was developed at the Federal University of Rio Grande do Sul – UFRGS. The experimental delineation compared the addition of two sources of organic matter (sewage sludge – SS and cover soil from that same region - CS) to basalt waste rock (BWR) against the sole use of cover soil, which a current restoration technique. The graminoid Avena strigosa (black oats) and soil fertility tests were used as indicators of soil conditions. Amending BWR with SS led to the best physical and chemical conditions and the highest production of dry matter in comparison to the use of CS as amendment or its single use as cover soil. These results show that mixing SS to BWR can be used as a substitute for cover soil during the environmental restoration of basalt quarries, further contributing to the final disposal of these materials

Water hyacinth composting as a waste management strategy : a systematic review

Macrophytes proliferation problem is worldwide know resulting in impacts on natural environment, human health and economic activities. These organisms have several parameters resilience, which ensures high rate of reproduction and proliferation, hindering their management. As a management difficulty consequence, however, solutions are sought to disposal this large amount of macrophytes, such as composting and fertilizer production. Thus, this study aims to conduct a systematic literature review in Scientific Platforms Science Direct and Scopus, identifying current status of macrophytes composting process, main methods, analyses and results obtained, in order to contribute in innovation studies to convert this type of weed into fertilizer. The general words source in titles, summary, or keywords specified by author were “Macrophyte” or “water hyacinth” and “compost” or “composting”. Only articles dating from the last 20 years were maintained. Macrophyte composting process interest is addressed around the world because of their potential environmental, economic and social impacts, mainly for Eichhornia crassipes. Natural aeration predominates (56%) with composting time equal to or less than 60 days. Humidity control is essential (around 60%) like macrophytes dehydration prior to the composting process beginning. The significant quantity cellulose requires previous comminution and/or the cellulose-degrading inoculants addition. Composting process operational parameters are not standardized. Micro and macro nutrients richness can be considered for next evolutionary composting studies stage for this plant type, either by organic matter sources characteristics and/or mineral sources addition

Cost assessment of the Brazilian construction and demolition waste recycling plant : a case study of Porto Alegre

The construction activities generate representative amount of Construction and Demolition Waste (CDW) around the world. Brazilian City Halls collected about 45 million tons/year. CDW recycling plants needs to be economically viable. The characteristics of recycling plants and future expectations vary around the world. Thus, the cost analysis needs to be adapted to the local reality and future scenarios should be evaluated. In this context, the objective of this paper is to evaluate the CDW recycling plant costs in Brazil. Two scenarios are tested, actual Scenario (1) and future Scenario (2), with air jig. Four steps are performed: literature review, inventory of the inputs, economic indicators analysis, and sensitivity analysis of alternative solutions. The results suggest that both scenarios do not reach positive economic indicators (IRR, NPV and Payback). The Fixed Costs are the main influence on the results, mainly due to the acquisition of Equipment. The Variable Costs represent, in Scenario 1 and 2, 18% and 10% of their Total Fixed Costs, respectively. Scenario 1, however, has possible conversion into positive IRR easier than for Scenario 2, once the Air Jig influence significantly in the increment of costs. A Government subsidy tested would not make the CDW Recycling Scenarios economically attractive. Only Scenario 1 can achieve positive results, however without the acquisition costs of Land, Equipment and Vehicles. Counterparts with the City Hall, in exchange for the supply of these inputs, would not influence the positive results. The use of new technologies maybe will be possible after the recycled aggregate market is consolidated in Brazil

Sample design for Brazilian construction and demolition waste

Resíduos da Construção e Demolição (CDW) estão entre os mais gerados em vários países, resultando em uma preocupação com este tipo de resíduo. Vários estudos são realizados com o CDW, muitos deles com o objetivo de avaliar a realidade técnica, econômica, social e ambiental de uma região, cidade ou país. Para este fim, é importante aplicar métodos estatísticos que apresentem representatividade da amostra. O trabalho tem como objetivo identificar um conjunto de amostras representativas de RCD brasileiro, para estudos que visam sua aplicação com substituição do agregado natural pelo reciclado. Foi utilizado o projeto fatorial 2k em conjunto com a divisão de materiais de interesse em quartis. Três conjuntos de amostras foram definidos, fixando dois tipos de materiais, de acordo com o planejamento fatorial 2k, seguido da definição dos terceiros valores. Como resultado, foi possível identificar a aplicabilidade da união dos métodos estatísticos, o que resultou em 16 amostras. Os três conjuntos de amostras avaliadas puderam ser aplicados. No entanto, a determinação dos valores de argamassa e concreto, seguida da determinação dos valores da cerâmica foi a mais adequada.Waste from Construction and Demolition (CDW) are among the most generated in several countries resulting in an emerging concern with this kind of waste. Thus, several studies are conducted with the CDW, many of them aimed to evaluate the technical, economic, social and environmental reality of a region, city or country. To this end, it is important to apply statistical methods that achieve both sample sufficiency and representativeness. Hence, the present work aims to identify a set of samples representative of the Brazilian CDW, mainly for studies aimed at its application as a large aggregate in substitution to the natural aggregate. The 2k factorial project was used in conjunction with the division of materials of interest in the RCC in quartiles. Three sets of samples were defined, fixing two types of materials, according to the factorial design 2k, followed by the definition of the third values. As a result, it was possible to identify the applicability of the union of the statistical methods, which resulted in 16 samples. The three sets of samples evaluated were able to be applied. However, the determination of the mortar and concrete values, followed by the determination of the values of Ceramics (CA3) was more adequate

Systematization and implementation of na environmental education project for the valorization of compostable solid waste in an integrated municipal waste plan

Este estudo apresenta resultados da educação socioambiental sistematizada como ferramenta de gestão e valorização de resíduos sólidos. Por meio de um convênio entre o Laboratório de Estudos Ambientais para Metalurgia (LEAMet/UFRGS), e as Secretarias do Meio Ambiente (SEMAM) e da Educação (SMED) de Novo Hamburgo (NH) RS, para viabilizar projetos contidos no Plano Municipal de Gestão Integrada de Resíduos Sólidos do Município (PMGIR) e implantar programas socioeducativos, promovendo a redução dos resíduos na coleta comum e/ou seletiva de NH. Este trabalho tem como objetivo sensibilizar, organizar, orientar e facilitar práticas em campo para a gestão de resíduos e desenvolvimento de projetos e boas práticas de educação socioambiental. A metodologia inicia com o cadastro das escolas para as ações pedagógicas, elaboração de um plano de ação, oficinas de compostagem e registro das atividades em um diário de campo. A coleta de dados e a produção de conteúdos foi realizada através de Pesquisa-ação. As atividades realizadas correspondem às oficinas de educação socioambiental e Compostagem, destinadas à comunidade escolar (alunos, pais, professores e funcionários) e ao coletivo educador. As escolas capacitadas receberam conjuntos de caixas composteiras, disponibilizadas pela SEMAM. Participaram das oficinas de treinamento e receberam composteiras 57 escolas deste município, onde 1747 pessoas foram capacitadas e sensibilizadas. Entende-se que esta iniciativa tenha sido um protótipo de sucesso deste tipo de programa e que pode ser replicado para outras escolas e até mesmo para outros municípios.This study presents results of systematic socioenvironmental education as a tool for the management and recovery of solid waste. This tool was developed through an agreement between Enviromental Studies Laboratory (LEAMet/UFRGS)and Secretariats of Environment (SEMAM) and Education (SMED) from Novo Hamburgo (NH), to enable projects contained in the Municipal Plan for Integrated Management of Solid Waste (PMGIR) and implement socio-educational programs, promoting the reduction of waste in the common and/or selective collection of NH. This work aims to raise awareness, organize, guide and facilitate field practices for waste management and development of projects and socio-environmental education good practices. The methodology begins with the registration of schools for pedagogical actions, preparation of an action plan, composting workshops and recording activities in a field diary. Data collection and content production were carried out through Action Research. The activities carried out correspond to the socio-environmental education and composting workshops, facing the school community (students, parents, teachers and employees) and the educating collective. Trained schools received sets of composting boxes, donated by SEMAM. 57 schools in this municipality participated in the training workshops and received composting boxes and 1747 people were trained and sensitized. It is understood that this initiative has been a successful prototype of this type of program and that it can be replicated to other schools and even to other municipalities

Prevenction of the acid mine drainage (AMD) by blending coal tail and a slag from an eletric steel plant

Uma das tecnologias de prevenção da geração da Drenagem Ácida de Minas (DAM) é o método de aditivos alcalinos. A alcalinidade impede as reações de oxidação da pirita, evitando a geração de acidez e a solubilização de metais em meio aquoso. Assim, o objetivo deste trabalho é estudar o uso de escória do forno panela de aciaria elétrica como aditivo alcalino para o controle da geração de DAM. O rejeito de carvão foi obtido em uma mina de carvão do Estado do Rio Grande do Sul e a escória foi fornecida por uma usina siderúrgica semi-integrada. Inicialmente, caracterizaram-se os materiais pelo método de contabilização de ácidos e bases. Após, realizaram-se ensaios cinéticos em células úmidas pelo método ASTM D 5744-96. A qualidade da água de percolação nas células úmidas foi analisada em termos de pH, Eh e concentração de metais e sulfatos. Os resultados demonstram que a DAM pode ser evitada pela mistura do rejeito de carvão com a escória em uma proporção de 3:1. Pode-se concluir que a disposição conjunta de escória de aciaria com rejeito de carvão é uma alternativa viável para o controle da geração de DAM em minerações de carvão.Alkaline additive is an effective method for controlling acid mine drainage (AMD). Alkalinity hinders pyrite oxidation reactions, avoiding acidity and metals solubilization in water. Thus, the aim of this work is to study the use of a ladle furnace slag as an alkaline additive for controlling AMD. The coal tailing was obtained from a coal mine in Rio Grande do Sul State and the slag from a minimill steel plant. Initially the materials were characterized by the acid-base accounting method. After, kinetic tests in humidity cells were carried out according to ASTM D 5744-96 method. The leaching water was evaluated in terms of pH, Eh, metals, and sulfates concentration. The results showed that AMD could be avoided by mixing the coal’s tailings with slag at 3:1 proportion. It is demonstrated that ladle furnace slag is a suitable alkaline material for AMD prevention in coal tailings deposits

Processo para redução do teor de cloro em poeiras de aciaria

GerdauUniversidade Federal do Rio Grande do SulEngenhariaDepositad