Feasibility studies on using microwave-heating techniques for recycling lead waste

Lead is present everywhere in the environment and has been defined as one of the greatest threats to the human health. In this paper, attempts have been made to study a way of recycling the lead produced from waste usage and disposed of in such a way as to avoid degrading the surrounding environment. In order to contain the waste, recycled asphalt material is mixed with the lead and then heated with microwave energy. This is an attempt to solidify and reduce the lead contaminants and use the final product as sub-base material in road pavement construction. The microwave heating of the specimens is carried out with 30%, 50%, 80% and 100% of power at 800W. The optimum power mode is used to compare with the conventional heating of asphalt with sulfur additive. The results are characterized by compact density, permeability, and subjected to toxicity test with regards to lead concentration. A mechanical test to evaluate the stability is also performed on the three methods of solidification and to prove that microwave zapping method allow to convert into an environmentally stable material for recycling without having to be deposited in a landfill site.

Final report : task 4 : waste minimisation in construction

The Regenerating Construction Project for the CRC for Construction Innovation aims to assist in the delivery of demonstrably superior ‘green’ buildings. Components of the project address eco-efficient redesign, achieving a smaller ecological footprint, enhancing indoor environment and minimising waste in design and construction. The refurbishment of Council House 1 for Melbourne City Council provides an opportunity to develop and demonstrate tools that will be of use for commercial building refurbishment generally. It is hoped that the refurbishment will act as an exemplar project to demonstrate environmentally friendly possibilities for office building refurbishment.

Decision support in using fibre reinforced polymer (FRP) composites in rehabilitation of concrete bridge structures

This paper compares and reviews the recommendations and contents of the guide for the design and construction of externally bonded FRP systems for strengthening concrete structures reported by ACI committee 440 and technical report of Externally bonded FRP reinforcement for RC structures (FIB 14) in application of carbon fiber reinforced polymer (CFRP) composites in strengthening of an aging reinforced concrete headstock. The paper also discusses the background, limitations, strengthening for flexure and shear, and other related issues in use of FRP for strengthening of a typical reinforced concrete headstock structure such as durability, de-bonding, strengthening limits, fire and environmental conditions. A case study of strengthening of a bridge headstock using FRP composites is presented as a worked example in order to illustrate and compare the differences between these two design guidelines when used in conjunction with the philosophy of the Austroads (1992) bridge design code.

Waste minimisation in office refurbishment projects : an Australian perspective

The refurbishment of commercial buildings is growing as a percentage of overall construction activity in Australia and this trend is likely to continue. Refurbishment generates a significant waste stream much of which is potentially reusable or recyclable. Despite this potential, several factors are known to unnecessarily inhibit the amount of recycling that actually occurs on renovation projects. In order to identify the reasons causing this reluctance, a process of project monitoring and expert consultation was carried out. Twenty three experts experienced in commercial refurbishment projects and three waste contractors with specific knowledge of construction waste were interviewed. Records of receipts for waste from a case study project reveal three principal factors inhibiting recycling rates: the presence of asbestos in the building; the continued occupation of the building during construction; and the breaking up of a large project into small separate contracts thereby reducing economies of scale. To ascertain the potential for improvement, current rates for reuse and recycling of materials were collected from the experts. The results revealed a considerable variation in practice between companies and indicated key areas which should be targeted to improve performance.

The efficacy of waste management plans in Australian commercial construction refurbishment projects

Renovation and refurbishment of the existing commercial building stock is a growing area of total construction activity and a significant generator of waste sent to landfill in Australia. A written waste management plan (WMP) is a widespread regulatory requirement for commercial office redevelopment projects. There is little evidence, however, that WMPs actually increase the quantity of waste that is ultimately diverted from landfill. Some reports indicate an absence of any formal verification or monitoring process by regulators to assess the efficacy of the plans. In order to gauge the extent of the problem a survey was conducted of twenty four consultants and practitioners involved in commercial office building refurbishment projects to determine the state of current practice with regard to WMPs and to elicit suggestions with regard to ways of making the process more effective. Considerable variation in commitment to recycling policies was encountered indicating a need to revisit waste minimisation practices if the environmental performance of refurbishment projects is to be improved.

Planning for SMEs’ Proactive Waste Management in Office Building Retrofit Projects

Office building retrofit projects face many challenges for on-site waste management. While the projects themselves have the potential for a significant level of reuse and recycling from decon-struction and demolition, their unique characteristics often prohibit direct application of existing waste management systems, which are typically based on managing waste generated through new material application in new build projects. Moreover, current waste management plans include no stimuli to involve Small and Medium Enterprises (SMEs) for on-site waste management. As SMEs carry out the majority of on-site work as subcontractors, their active involvements will result in more proactive approaches to waste management and enhance project delivery. This paper discusses the interim results of a continuing research aimed at engaging SMEs in the planning processes of waste management through the collaboration between subcontractors and main contractors of retrofitting projects. It introduces a conceptual model for SMEs to proactively plan and manage on-site waste generation for both deconstruction and construction stages, before traditional waste management plans by the main contractor come into place. The model also suggests a collaboration process between SMEs as subcontractors and large companies as the main contractor to improve the involvement and performance of SMEs in waste management of office building retrofit projects.

New strategies of managing waste in office building retrofit projects

Retrofit projects are different from newly-built projects in many respects. A retrofit project involves an existing building, which imposes constraints on the owners, designers, operators and constructors throughout the project process. Retrofit projects are risky, complex, less predictable and difficult to be well planned, which need greater coordination. For office building retrofit project, further restrictions will apply as these buildings often locate in CBD areas and most have to remain operational during the progression of project work. Issues such as site space, material storage and handling, noise and dust, need to be considered and well addressed. In this context, waste management is even more challenging with small spaces for waste handling, uncertainties in waste control, and impact of waste management activities on project delivery and building occupants. Current literatures on waste management in office building retrofit projects focus on increasing waste recovery rate based on project planning, monitoring and stakeholders’ collaboration. However, previous research has not produced knowledge of understanding the particular retrofit processes and their impact on waste generation and management. This paper discusses the interim results of a continuing research on new strategies for waste management in office building retrofit projects. Firstly based on the literature review, it summarizes the unique characteristics of office building retrofit projects and their influence on waste management. An assumption on waste management strategies is formed. Semi-structured interviews were conducted towards industry practitioners and findings are then presented in the paper. The assumption of the research was validated in the interviews from the opinions and experiences of the respondents. Finally the research develops a process model for waste management in office building retrofit projects. It introduces two different waste management strategies. For the dismantling phase, waste is generated fast along with the work progress, so integrated planning for project delivery and waste generation is needed in order to organize prompt handling and treatment. For the fit-out phase, the work is similar as new construction. Factors which are particularly linked to generating waste on site need to be controlled and monitored. Continuing research in this space will help improve the practice of waste management in office building retrofit projects. The new strategies will help promote the practicality of project waste planning and management and stakeholders’ capability of coordinating waste management and project delivery.

Nourishing or polluting : redefining the role of waste in the fashion system

Waste is intrinsic to the fashion system. Fashion is predicated on built-in obsolescence, and as such outmoded garments are rapidly discarded to charity shops or landfill. However, the story of fashion is also one of abundance and extravagance in design ideas. Every season there are new design details – prints, embroidery, embellishments, shapes and textures. This excess of ideas is in itself another form of waste, albeit one that is culturally nourishing. The grave of a fashion garment may also be the grave of a season’s research and creativity. This paper compares the tangible waste of the industry with its intangible waste, namely fashion’s creativity and cultural excess. Fashion’s excess and abundance of trends and ideas makes any move to curb the environmental impact difficult. For all practitioners of fashion – whether designers or consumers – the waste and excess inherent in the fashion system is a difficult ethical terrain to negotiate. However, inverting the wasteful phases of the production cycle can help reframe waste from pollution to a source of nourishment for future practice. While creative excesses of designers may be ‘wasted’ after a season, fashion styles and tropes are recycled and reinvented, with the once passé styles and design ideas from previous years revalorized and returned into the fashion system. Similarly, material garments acquire new value through entering or re-entering the second hand or vintage markets. Design processes can utilise pre or post-consumer textile waste, or eliminate waste through design. In these processes, waste becomes the primary source of nourishment for future fashion cycles.

Synthetic reevesite-like material as a visible light photocatalyst for the decontamination of water

A synthetic reevesite-like material has been shown to decolorize selected dyes and degrade phenolic contaminants photocatalytically in water when irradiated with visible light. This material can photoactively decolorize dyes such as bromophenol blue, bromocresol green, bromothymol blue, thymol blue and methyl orange in less than 15 min under visible light radiation in the absence of additional oxidizing agents. Conversely, phenolic compounds suc has phenol, p-chlorophenol and p-nitrophenol are photocat- alytically degraded in approximately 3hwith additional H2O2 when irradiated with visible light. These reactions offer potentially energy effective pathways for the removal of recalcitrant organic waste contaminants.

Laboratory study on the performance of recycled concrete aggregates blended with reclaimed asphalt pavement as pavement granular material

Production of recycled concrete aggregates (RCA) from construction and demolition (C&D) waste has become popular all over the world since the availability of land spaces are limited to dispose. Therefore it is important to seek alternative applications for RCA. The use of RCA in base and sub-base layers in granular pavement is a viable solution. In mechanistic pavement design, rutting (permanent deformation) is considered as the major failure mechanisms of the pavement. The rutting is the accumulation of permanent deformation of pavement layers caused by the repetitive vehicle load. In Queensland, Australia, it is accepted to have the maximum of 20% of reclaimed asphalt pavement (RAP) in RCA and therefore, it is important to investigate the effect of RAP on the permanent deformation properties of RCA. In this study, a series of repeated load triaxial (RLT) tests were conducted on RCA blended with different percentage of RAP to investigate the permanent deformation and resilient modulus properties of RCA. The vertical deformation and resilient modulus values were used to determine the response of RCA for the cyclic loading under standard pressure and loading conditions.

Assessment of recycled concrete aggregates as a pavement material

Population increase and economic developments can lead to construction as well as demolition of infrastructures such as buildings, bridges, roads, etc resulting in used concrete as a primary waste product. Recycling of waste concrete to obtain the recycled concrete aggregates (RCA) for base and/or sub-base materials in road construction is a foremost application to be promoted to gain economical and sustainability benefits. As the mortar, bricks, glass and reclaimed asphalt pavement (RAP) present as constituents in RCA, it exhibits inconsistent properties and performance. In this study, six different types of RCA samples were subjected classification tests such as particle size distribution, plasticity, compaction test, unconfined compressive strength (UCS) and California bearing ratio (CBR) tests. Results were compared with those of the standard road materials used in Queensland, Australia. It was found that material type ‘RM1-100/RM3-0’ and ‘RM1-80/RM3-20’ samples are in the margin of the minimum required specifications of base materials used for high volume unbound granular roads while others are lower than that the minimum requirement.

Estimates of lost material stock of buildings and roads due to the great east Japan earthquake and tsunami

This article describes research conducted for the Japanese government in the wake of the magnitude 9.0 earthquake and tsunami that struck eastern Japan on March 11, 2011. In this study, material stock analysis (MSA) is used to examine the losses of building and infrastructure materials after this disaster. Estimates of the magnitude of material stock that has lost its social function as a result of a disaster can indicate the quantities required for reconstruction, help garner a better understanding of the volumes of waste flows generated by that disaster, and also help in the course of policy deliberations in the recovery of disaster-stricken areas. Calculations of the lost building and road materials in the five prefectures most affected were undertaken. Analysis in this study is based on the use of geographical information systems (GIS) databases and statistics; it aims to (1) describe in spatial terms what construction materials were lost, (2) estimate the amount of infrastructure material needed to rehabilitate disaster areas, and (3) indicate the amount of lost material stock that should be taken into consideration during government policy deliberations. Our analysis concludes that the material stock losses of buildings and road infrastructure are 31.8 and 2.1 million tonnes, respectively. This research approach and the use of spatial MSA can be useful for urban planners and may also convey more appropriate information about disposal based on the work of municipalities in disaster-afflicted areas.

Determinants of trade in recyclable wastes: Evidence from commodity-based trade of waste and scrap

This paper examines factors that affect the trade of recyclable waste in both exporting and importing countries. To this end, we employ two important elements: first, we adopt a gravity model in our empirical methodology; second, we select five waste and scrap commodities and undertake estimations using commodity-level trade data. We demonstrate that, the higher the wage/per capita GDP/population of an importing country, the more recyclable wastes it imports. This result suggests that the demand for final goods and, accordingly, the demand for materials including recycled material, have strong effects on the import volume of recyclable waste. Moreover, this implies that the imports of a developing country from developed countries increase with expanding industrial activity and economic growth. We find no evidence for a pollution haven for wastes and recycling.

Assessment of permeable covers for odour reduction in piggery effluent ponds. 2. Field-scale trials

The efficacy of supported covers was investigated under field conditions using a series of prototypes deployed on an anaerobic pond treating typical piggery waste. Research focused on identifying effective cover support materials and deployment methods, quantifying odour reduction, and estimating the life expectancy of various permeable cover materials. Over a 10-month period, median odour emission rates were five to eight times lower from supported straw cover surfaces and a non-woven, spun fibre polypropylene weed control material than from the adjacent uncovered pond surface. While the straw covers visually appeared to degrade very rapidly, they continued to reduce odour emissions effectively. The polypropylene cover appeared to offer advantages from the perspectives of cost, reduced maintenance and ease of manufacture.