Exploitation of iron ore tailing for the development of ceramic tiles

India ranks as the sixth largest producer of iron ore in the world. The current practice of washing iron ore in India generates as high as 18 million tonnes of tailings per year. These tailings are stored in massive ponds and pose environmental hazards. Safe disposal or utilisation of these materials thus remains a challenging task for the iron ore industry in India. The present paper describes a new development in managing these tailings by converting them into value added products such as ceramic floor and wall tiles for building application. These tiles have high strength and hardness compared to conventional tiles and conform to most of the EN standards. Energy economy and lower production costs are some other benefits.     

The building materials decree: an example of a Dutch regulation based on the potential impact of materials on the environment

Some 20 years ago Dutch society became very aware of the problem of the increasing production of waste materials and of the need to find solutions. Technical solutions had to be developed and introduced into society. Due to the discovery of many soil pollution problems and other environmental calamities, people asked for clear criteria on which proper and safe solutions could be based. Therefore a large number of environmental aspects had to be taken into account in the developing field of environmental policy. The Dutch building materials decree is one of the steps on the road towards a sustainable society. The decree is based on the soil protection act and the surface water protection act. The decree gives quality criteria for the application and re-use of stony materials and earth used as building materials. No difference is made between primary materials, secondary materials and waste materials. The decree is applicable in case these materials are used in constructions where they are in contact with rain, surface water and ground water (e.g. in embankments, road building, outside walls of buildings, foundations and roofs). For implementation of the decree in the construction industry it was necessary to develop standards, methods for testing and certification schemes. In order to guarantee independent testing and judgement, laboratories had to meet quality standards put forward in an accreditation scheme. Although this legislation does not cover all environmental aspects, it has proved to be an important element in judging the environmental quality of construction materials in a direct or indirect way, and a contribution to the management of waste materials. The question of clear and fair criteria was easily put forward. Answering this question, however, turned out to be a complex task in which a great number of aspects had to be considered and a great many tools had to be developed, checked and thoroughly discussed. In some cases practical choices had to be made in order to prevent an unclear situation continuing too long. After an introduction period of three years, the decree came into full operation on 1 July 1999.     

Genotoxicity of substances extracted from construction materials

Construction waste such as road pavement and concrete is estimated to constitute about 50% of the total industrial waste in Japan, and the recycling of such material has recently become a prominent topic among construction engineers. It has also been suggested that various types of industrial waste be utilized as components of construction materials. This paper investigates the environmental safety of certain materials in terms of the elutions and genotoxicities of these substances. The substances extracted from some materials, such as emulsifier, ash, and sediment, were found to have genotoxic characteristics. The dose-related responses of the various materials and their genotoxic strengths are shown. Received: June 16, 1998 / Accepted: September 7, 1999     

Synthesis of artificial aggregates and their impact on performance of concrete: a review

Infrastructure development and urbanization have created a demand for the prime construction material—"Concrete." The manufacture of concrete has pressurized the aggregate supply chain for over-exploitation of natural resources leading to eco-detrimental impacts besides environmental regulations. The auxiliary sectors of the construction industry are creating a vast quantum of by-products and waste, causing environmental degradation, which concerns governing bodies. Developing aggregates artificially using these by-products and waste materials would be an eco-friendly and economical solution. This article provides an overview of the ingredients, production methods, and factors influencing the characteristics of such sustainable building materials, which can substitute conventional aggregates in the near future.

     

Environmental impact of APC residues from municipal solid waste incineration: reuse assessment based on soil and surface water protection criteria

Waste management and environmental protection are mandatory requirements of modern society. In our study, air pollution control (APC) residues from municipal solid waste incinerators (MSWI) were considered as a mixture of fly ash and fine particulate solids collected in scrubbers and fabric filters. These are hazardous wastes and require treatment before landfill. Although there are a number of treatment options, it is highly recommended to find practical applications rather than just dump them in landfill sites. In general, for using a construction material, beyond technical specifications also soil and surface water criteria may be used to ensure environmental protection. The Dutch Building Materials Decree (BMD) is a valuable tool in this respect and it was used to investigate which properties do not meet the threshold criteria so that APC residues can be further used as secondary building material. To this end, some scenarios were evaluated by considering release of inorganic species from unmoulded and moulded applications. The main conclusion is that the high amount of soluble salts makes the APC residues a building material prohibited in any of the conditions tested. In case of moulding materials, the limits of heavy metals are complied, and their use in Category 1 would be allowed. However, also in this case, the soluble salts lead to the classification of "building material not allowed". The treatments with phosphates or silicates are able to solve the problem of heavy metals, but difficulties with the soluble salts are still observed. This analysis suggests that for APC residues to comply with soil and surface water protection criteria to be further used as building material at least a pre-treating for removing soluble salts is absolutely required.     

Legacy PCB building remediation

Polychlorinated biphenyls (PCBs) came onto the scene as an environmental threat quickly after they were discovered in humans and wildlife by Jensen in 1966. By October 1970, it was reported that PCBs were “truly ubiquitous pollutants” as PCBs were found at detectable concentrations in environmental samples throughout the world. Before 1971, the U.S. Environmental Protection Agency (EPA) reported that 26% of PCBs sold were used in open‐end use applications, such as caulks, sealants, plasticizers, surface coatings, ink, adhesive, and carbonless paper. Processing and distribution of PCBs in commerce were largely banned in the U.S. after July 1979 with certain continued uses authorized by the EPA. While PCBs were banned a long time ago, the ban had no immediate tangible effect on the continued use of regulated levels of PCBs in buildings constructed before the bans were implemented. Legacy buildings with PCB‐containing building materials continue to represent potential sources of indoor air, dust, outdoor air, and soil contamination. Where PCBs are present in building materials, they have the potential to pose a risk to building occupants. Proper removal of PCB‐containing materials is a highly effective approach to abating the risk. The removal can range from targeting specific building PCB‐containing materials through demolition of the building. Engineering and administrative controls can also be useful tools when addressing the risks posed by PCB‐containing materials.     

Inertization of hazardous dredging spoils

Vitrification and production of ceramics materials starting from sediment excavated from Venice lagoon is described. This sediment is classified as toxic waste because contains several heavy metal ions and organic pollutants and was successfully vitrified at 1200-1350 degrees C. Twenty weight percentage of glass cullet, coming from a community glass recycling program, was added to the raw materials, previously calcined at 900 degrees C, as a way of adjusting the variations of composition of the individual sediment batches. Chemical durability (leaching) tests showed that the optimized glass compositions are inert, and thus not only volume reduction but also inertization of the waste was obtained by this process. Moreover, the economics of the entire process was analysed. The valorization of the waste was accomplished by the subsequent processing of the glass derived from the inertization. Glass ceramic materials were produced by viscous phase sintering of pressed glass powders which crystallized during the densification process. Sintered glass ceramic products had good mechanical characteristics (HV = 7.5 GPa, bending strength 150 +/- 8 MPa), making them suitable for applications in the building industry.     

Cement-based materials as containment systems for ash from hospital waste incineration

Waste generation has increased considerably worldwide in the last decades. As a consequence, incineration became an alternative for reducing waste volume, leading to the generation of ash as a new type of waste. The new cement-ash composite systems have been tested for future applications in building materials. Having in mind the previous data and scientific reports, the objective of the present study is oriented to evaluate the additions of hospital waste ash in cement matrices to be potentially used as construction elements. This involved the assessment of the effect of the additions (different proportions of ash and metal-spiked ash) on the physico-mechanical properties of the building materials and the leachability of metals. The experiences show the feasibility of including hospital waste ashes in masonry blocks or other similar products.     

Fly ash of mineral coal as ceramic tiles raw material

The aim of this work was to evaluate the use of mineral coal fly ash as a raw material in the production of ceramic tiles. The samples of fly ash came from Capivari de Baixo, a city situated in the Brazilian Federal State of Santa Catarina. The fly ash and the raw materials were characterized regarding their physical chemical properties, and, based on these results; batches containing fly ash and typical raw materials for ceramic tiles were prepared. The fly ash content in the batches varied between 20 and 80 wt%. Specimens were molded using a uniaxial hydraulic press and were fired. All batches containing ash up to 60 wt% present adequate properties to be classified as several kinds of products in the ISO 13006 standard () regarding its different absorption groups (pressed). The results obtained indicate that fly ash, when mixed with traditional raw materials, has the necessary requirements to be used as a raw material for production of ceramic tiles.     

废弃印刷线路板中材料的资源化回收利用技术

废弃印刷线路板（WPCBs）既有污染环境的一面,又有可资源化回收利用的一面.通过机械物理法、热解、超临界流体氧化和离子液体溶解等方法对其进行分离和回收金属和非金属材料.初步分选的金属需要进一步提纯以实现高附加值.而非金属材料可以用热解法、微波处理、超临界流体技术、等离子技术等技术进行产气和能量回收,也可以通过制备建筑材料或填料和其它功能村料进行物料回收.总之,对WPCBs进行适当地处理不但可以减轻环境压力,还可以变废为宝,实现资源再生利用.     

A web-based Decision Support System for the optimal management of construction and demolition waste

Wastes from construction activities constitute nowadays the largest by quantity fraction of solid wastes in urban areas. In addition, it is widely accepted that the particular waste stream contains hazardous materials, such as insulating materials, plastic frames of doors, windows, etc. Their uncontrolled disposal result to long-term pollution costs, resource overuse and wasted energy. Within the framework of the DEWAM project, a web-based Decision Support System (DSS) application - namely DeconRCM - has been developed, aiming towards the identification of the optimal construction and demolition waste (CDW) management strategy that minimises end-of-life costs and maximises the recovery of salvaged building materials. This paper addresses both technical and functional structure of the developed web-based application. The web-based DSS provides an accurate estimation of the generated CDW quantities of twenty-one different waste streams (e.g. concrete, bricks, glass, etc.) for four different types of buildings (residential, office, commercial and industrial). With the use of mathematical programming, the DeconRCM provides also the user with the optimal end-of-life management alternative, taking into consideration both economic and environmental criteria. The DSS's capabilities are illustrated through a real world case study of a typical five floor apartment building in Thessaloniki, Greece.     

Recycled Polyethylene Composites Reinforced with Jute Fabric from Sackcloth: Part I-Preparation and Preliminary Assessment

In recent times, environmental safety has been on priority in the development of new materials leading to a recycling and reuse approach to conserve the materials resources. This has resulted in more focus on the application of natural materials such as lignocellulosic fibers. This paper presents the characterization of continuous and aligned jute fabrics obtained from new and used sacks as well as the preparation and characterization of their composites incorporated into recycled polyethylene or as isolated pieces up to 40 wt%. These environmentally friendly composites were subjected to bend test and the fracture surface analyzed by SEM. The fabric from new sacks showed greater damage tolerance than that from the used sacks. The flexural stress increased steadily with increasing used fabric content up to 30 wt%, which is explained using fractographic studies on ruptured specimens. Used jute fabric composites are found to be viable alternative materials for low strength conventional materials based on cost–performance comparison with conventional materials.     

Eco-efficient waste glass recycling: Integrated waste management and green product development through LCA

As part of the EU Life + NOVEDI project, a new eco-efficient recycling route has been implemented to maximise resources and energy recovery from post-consumer waste glass, through integrated waste management and industrial production. Life cycle assessment (LCA) has been used to identify engineering solutions to sustainability during the development of green building products. The new process and the related LCA are framed within a meaningful case of industrial symbiosis, where multiple waste streams are utilised in a multi-output industrial process. The input is a mix of rejected waste glass from conventional container glass recycling and waste special glass such as monitor glass, bulbs and glass fibres. The green building product is a recycled foam glass (RFG) to be used in high efficiency thermally insulating and lightweight concrete. The environmental gains have been contrasted against induced impacts and improvements have been proposed. Recovered co-products, such as glass fragments/powders, plastics and metals, correspond to environmental gains that are higher than those related to landfill avoidance, whereas the latter is cancelled due to increased transportation distances. In accordance to an eco-efficiency principle, it has been highlighted that recourse to highly energy intensive recycling should be limited to waste that cannot be closed-loop recycled.     

生物膜填料塔净化工业废气用填料的研究

以净化低浓度甲苯废气为对象，采用实验室及工业化规模的 生物塔料塔对轻质陶块、瓷环、不锈钢环和塑料环4种填料进行选择研究，结果表明：轻质陶块是一种优质、廉价的废气处理用生物膜填料塔的填料；4种填料的净化性能及经济性的综合排序为：轻质陶块＞瓷环＞不锈钢环＞塑料环；用轻质陶块填充的工程应用生物膜填料塔，在生物挂膜约10d时，甲苯的净化效率可达90％以上，且设备运行稳定。     

Spectral cullet classification in the mid-infrared field for ceramic glass contaminants detection.

The presence of glass-like contaminants inside waste glass products, usually resulting from both industrial and differentiated urban waste collection, has greatly increased in recent years, due to the introduction to the market of a large amount of goods manufactured from ceramic glass. The presence of contaminants in the glass recycling streams reduces product quality and increases production costs. The detection of ceramic glass detection is an unresolved problem, as such material looks like normal glass and can only be detected by trained personnel. In this study an innovative approach to ceramic glass recognition, based on the spectral signature in the mid-infrared (MIR) field, was proposed and investigated. The study specifically addressed the spectral characterization of glass and ceramic glass fragments collected in a real recycling plant from two different production lines: coloured container glass and white container glass. To define suitable inspection strategies to separate the useful (glass) from the polluting (ceramic glass) materials at the recycling plants, fragments presenting different colour, thickness, size, shape and manufacturing were selected. Both dirty and clean cullet was considered. The analyses, carried out in the MIR spectral field (2280-4480 nm), show that ceramic glass and glass fragments can be recognized according to their different spectral signature. In particular, by selecting a specific wavelength ratio the two classes of materials can be rapidly recognized, suggesting the possibility of developing an integrated hardware and software sorting system for 'on-line' ceramic glass separation.     

Universities in capacity building in sustainable development: focus on solid waste management and technology.

This paper analyses some of the higher education and research capacity building experiences gained from 1998-2006 by Danish and Malaysian universities. The focus is on waste management, directly relating to both the environmental and socio-economic dimensions of sustainable development. Primary benefits, available as an educational legacy to universities, were obtained in terms of new and enhanced study curricula established on Problem-oriented Project-based Learning (POPBL) pedagogy, which strengthened academic environmental programmes at Malaysian and Danish universities. It involved more direct and mutually beneficial cooperation between academia and businesses in both countries. This kind of university reach-out is considered vital to development in all countries actively striving for global and sustainable development. Supplementary benefits were accrued for those involved directly in activities such as the 4 months of field studies, workshops, field courses and joint research projects. For students and academics, the gains have been new international dimensions in university curricula, enhanced career development and research collaboration based on realworld cases. It is suggested that the area of solid waste management offers opportunities for much needed capacity building in higher education and research, contributing to sustainable waste management on a global scale. Universities should be more actively involved in such educational, research and innovation programmes to make the necessary progress. ISWA can support capacity building activities by utilizing its resources--providing a lively platform for debate, securing dissemination of new knowledge, and furthering international networking beyond that which universities already do by themselves. A special challenge to ISWA may be to improve national and international professional networks between academia and business, thereby making education, research and innovation the key driving mechanisms in sustainable development in solid waste management.     

Preparation sequences and pretreatment optimization of alkali-activated red mud and blast furnace slag-based materials

Journal of Material Cycles and Waste Management - The preparation of alkali-activated materials from red mud for building materials is a promising way to solve the environmental pollution caused by...     

Physical-mechanical and environmental properties of sintered municipal incinerator fly ash

A step-wise treatment of Municipal Solid Waste (MSW) incinerator fly ash including washing, milling and sintering was investigated in order to manufacture ceramic materials with improved physical, mechanical and environmental properties and, possibly, to reduce the power input of the sintering process. An interpretation of the test results based on the microstructure of sintered products and sintering kinetic modeling was also attempted to identify the densification mechanisms. It was found that milling of washed fly ash represents a basic step for manufacturing high-density ceramic materials with very high compressive strengths (up to 500 N/mm2). A significant reduction in the power input of the sintering process (reduction of firing temperature from 1210 degrees C for washed fly ash to 1140 degrees C for milled-washed fly ash) is also achieved. A dense, well-sintered microstructure is formed through an intermediate-stage, liquid-phase sintering mechanism controlled by liquid-phase diffusion and grain shape accommodation. Such a microstructure is able to strongly immobilise heavy metals, thus giving good environmental properties to sintered product.     

Reuse of textile effluent treatment plant sludge in building materials

This study examines the potential reuse of textile effluent treatment plant (ETP) sludge in building materials. The physico-chemical and engineering properties of a composite textile sludge sample from the southern part of India have been studied. The tests were conducted as per Bureau of Indian Standards (BIS) specification codes to evaluate the suitability of the sludge for structural and non-structural application by partial replacement of up to 30% of cement. The cement-sludge samples failed to meet the required strength for structural applications. The strength and other properties met the Bureau of Indian Standards for non-structural materials such as flooring tiles, solid and pavement blocks, and bricks. Results generally meet most ASTM standards for non-structural materials, except that the sludge-amended bricks do not meet the Grade NW brick standard. It is concluded that the substitution of textile ETP sludge for cement, up to a maximum of 30%, may be possible in the manufacturing of non-structural building materials. Detailed leachability and economic feasibility studies need to be carried out as the next step of research.     

Marine dredged sediments as new materials resource for road construction

Large volumes of sediments are dredged each year in Europe in order to maintain harbour activities. With the new European Union directives, harbour managers are encouraged to find environmentally sound solutions for these materials. This paper investigates the potential uses of Dunkirk marine dredged sediment as a new material resource for road building. The mineralogical composition of sediments is evaluated using X-ray diffraction and microscopy analysis. Since sediments contain a high amount of water, a dewatering treatment has been used. Different suitable mixtures, checking specific geotechnical criteria as required in French standards, are identified. The mixtures are then optimized for an economical reuse. The mechanical tests conducted on these mixtures are compaction, bearing capacity, compression and tensile tests. The experimental results show the feasibility of the beneficial use of Dunkirk marine dredged sand and sediments as a new material for the construction of foundation and base layers for roads. Further research is now needed to prove the resistance of this new material to various environmental impacts (e.g., frost damage).