Use of recycled products in UK construction industry: An empirical investigation into critical impediments and strategies for improvement

© 2014 Elsevier B.V. All rights reserved.Construction industry consumes about half of all material resources taken from nature, and generates a large portion of waste to landfill. A way of tackling negative environmental impacts impending from continuous material extraction and waste generation is the use of recycled materials for construction projects. However, the use of recycled materials is yet to become a commonplace in construction industry. This study evaluates the factors hampering the use of recycled products in UK construction industry as well as strategies that could be adopted to enhance its use in the industry. In order to identify the impediments and critical strategies, a two-fold methodical approach was used. An unstructured interview preceded a quantitative questionnaire survey which was used to elicit broader industry practitioners' opinion. The study shows that designers rarely specify recycled products. This is due to lack of adequate information about quality and market availability of the products, negative perception from clients, and unexpectedly high cost of the products, despite its perceived low quality. The study suggests that a number of strategies could be adopted to promote the use of the products. These include allocation of points to the use of recycled products in sustainable design appraisal tools, governments legislative measures, improved collaboration between designers, contractors and materials suppliers, contractors involvement at earlier stage of design, improved education of the professionals about the products, and the use of tax break to influence the cost of the products. The findings of this study would therefore help policy makers, manufacturers and construction professionals to identify the factors hampering the use of recycled products for construction projects as well as the strategies that could be adopted in order to create market for the products

Crisis? What Crisis? The Normality of the Current Food Crisis

The 2005–8 food crisis was a shock to political elites, but in some respects the situation was normal. Food policies are failing to respond adequately to the squeeze on land, people, health and environment. Strong evidence of systems failure and stress, termed here New Fundamentals, ought to reframe twenty-first century food politics and effort. Yet so far, international discourse is too often narrow and technical. The paper suggests that 2005–8 reinforced how the dominant twentieth century productionist policy paradigm is running out of steam. This assumed that producing more food would resolve social problems. Yet distortions in markets, access and culture remain. At national and international levels of governance, despite realization of the enormity of the challenge ahead, there is still a belief in slow incremental change

Concentrations of organic contaminants in industrial and municipal bioresources recycled in agriculture in the UK

Many types of bioresource materials are recycled in agriculture for soil improvement and as bedding materials for livestock and have potential for transfer into plant and animal foods. Representative types of industrial and municipal bioresources were selected to assess the extent of organic chemical contamination, including: (i) land applied materials: treated sewage sludge biosolids), meat and bone meal ash (MBMA), poultry litter ash (PLA), paper sludge ash (PSA) and compost-like-output (CLO), and (ii) bedding materials: recycled waste wood (RWW), dried paper sludge (DPS), paper sludge ash (PSA) and shredded cardboard. The materials generally contained lower concentrations of polychlorinated dibenzo-pdioxins/dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (PCBs) relative to earlier reports, indicating the decline in environmental emissions of these established contaminants. However, concentrations of polycyclic aromatic hydrocarbons (PAHs) remain elevated in biosolids samples from urban catchments. Polybrominated dibenzo-p-dioxins/dibenzofurans (PBDD/Fs) were present in larger amounts in biosolids and CLO compared to their chlorinated counterparts and hence are of potentially greater significance in contemporary materials. The presence of non-ortho-polychlorinated biphenyls (PCBs) in DPS was probably due to non-legacy sources of PCBs in paper production. Emerging flame retardant compounds, including: decabromodiphenylethane (DBDPE)and organophosphate flame retardants (OPFRs), were detected in several of the materials. The profile of perfluoroalkyl substances (PFAS) depended on the type of waste category; perfluoroundecanoic acid (PFUnDA) was the most significant PFAS for DPS, whereas perfluorooctane sulfonate (PFOS) was dominant in biosolids and CLO. The concentrations of polychlorinated alkanes (PCAs) and di-2-ethylhexyl phthalate (DEHP) were generally much larger than the other contaminants measured, indicating that there are major anthropogenic sources of these potentially hazardous chemicals entering the environment. The study results suggest that continued vigilance is required to control emissions and sources of these contaminants to support the beneficial use of secondary bioresource materials

Carbon dioxide reduction in the building life cycle: a critical review

The construction industry is known to be a major contributor to environmental pressures due to its high energy consumption and carbon dioxide generation. The growing amount of carbon dioxide emissions over buildings’ life cycles has prompted academics and professionals to initiate various studies relating to this problem. Researchers have been exploring carbon dioxide reduction methods for each phase of the building life cycle – from planning and design, materials production, materials distribution and construction process, maintenance and renovation, deconstruction and disposal, to the material reuse and recycle phase. This paper aims to present the state of the art in carbon dioxide reduction studies relating to the construction industry. Studies of carbon dioxide reduction throughout the building life cycle are reviewed and discussed, including those relating to green building design, innovative low carbon dioxide materials, green construction methods, energy efficiency schemes, life cycle energy analysis, construction waste management, reuse and recycling of materials and the cradle-to-cradle concept. The review provides building practitioners and researchers with a better understanding of carbon dioxide reduction potential and approaches worldwide. Opportunities for carbon dioxide reduction can thereby be maximised over the building life cycle by creating environmentally benign designs and using low carbon dioxide materials

Nutrients from anaerobic digestion effluents for cultivation of the microalga Nannochloropsis sp. — Impact on growth, biochemical composition and the potential for cost and environmental impact savings

Microalgal biotechnology has yielded a range of products for different consumer markets, but large scale production for bulk commodities is limited by the cost and environmental impact of production. Nutrient requirements for large-scale production contribute significantly to the cost and environmental impact of microalgal biomass production and should subsequently be addressed by more careful sourcing of nutrients. This study assessed the use of nitrogen and phosphorus contained in effluents from anaerobic digestion of food waste to cultivate the marine microalga Nannochloropsis sp. With suitable dilution, effluent could replace 100% of nitrogen demands and 16% of required phosphorus, without significant impacts on growth or biomass productivity. Additional phosphorus requirements could be decreased by increasing the N:P molar ratio of the media from 16:1 to 32:1. Nannochloropsis sp. accumulated lipid up to 50% of dry weight under N-stress, with significant increases in the content of saturated and mono-unsaturated fatty acids. Using empirical data generated in this study, the cost and environmental impact of nitrogen and phosphorus supply was assessed versus the use of fertilizers for biomass and biodiesel production. Nutrient requirements predicted by the Redfield Ratio overestimating impacts by as much as 140% compared to empirical data. By utilising residual nutrients and optimising nutrient supply, the cost and environmental impact of nitrogen and phosphorus were decreased by >90% versus the use of artificial fertilizers. This study demonstrates the importance of using empirical data for process evaluation and how anaerobic digestate effluent derived nutrients can contribute to the sustainability of algal biomass production

Freeze/thaw protection of concrete with optimum rubber crumb content

This research looks at utilising an optimum quantity of rubber crumb as an air entraining ad-mixture in concrete, thus providing maximum freeze-thaw protection and maximum strength. Microscopic and chemical analysis was carried out on the rubber sample to investigate how rubber crumb entrains air and reacts with the surrounding concrete. The work contained two pilot studies that informed the main test methodology. The pilot studies examined the air content/compressive strength relationship (1) and freeze/thaw cycle durations (2). Pilot study 1 informed the main test program by identifying an optimum addition of rubber crumb to a concrete mix, which was found to be 0.6% by weight of concrete. The main test investigated the use of rubber crumb in providing freeze-thaw protection of a C40 concrete mix after 3 days of curing. A freeze-thaw test was carried out on three separate batches of concrete containing washed rubber crumb, unwashed rubber crumb and plain concrete respectively. It was found rubber crumb was effective in providing freeze/thaw protection in both cases. This work builds on recent work to identify the best practical solution for reducing waste and providing the maximum freeze/thaw protection for a cleaner production process