Nanoparticles based Permeable Reactive Barriers as an Eco-efficient Technology for nitrate remediation in soil and groundwater

The need to increase agricultural yield led, among others, to an increase in the consumption of nitrogen based fertilizers. As a consequence, there are excessive concentrations of nitrates, the most abundant of the reactive nitrogen (Nr) species, in several areas of the world. The demographic changes and projected population growth for the next decades, and the economic shifts which are already shaping the near future are powerful drivers for a further intensification in the use of fertilizers, with a predicted increase of the nitrogen loads in soils. Nitrate easily diffuses in the subsurface environments, portraying high mobility in soils. Moreover, the presence of high nitrate loads in water has the potential to cause an array of health dysfunctions, such as methemoglobinemia and several cancers. Permeable Reactive Barriers (PRB) placed strategically relatively to the nitrate source constitute an effective technology to tackle nitrate pollution. Ergo, PRB avoid various adverse impacts resulting from the displacement of reactive nitrogen downstream along water bodies. A four stages literature review was carried out in 34 databases. Initially, a set of pertinent key words were identified to perform the initial databases searches. Then, the synonyms of those initial key words were used to carry out a second set of databases searches. The third stage comprised the identification of other additional relevant terms from the research papers identified in the previous two stages. Again, databases searches were performed with this third set of key words. The final step consisted of the identification of relevant papers from the bibliography of the relevant papers identified in the previous three stages of the literature review process. The set of papers identified as relevant for in-depth analysis were assessed considering a set of relevant characterization variables

Patents as a Measure for Eco-Innovation

This paper examines the usefulness of patent analysis for measuring eco-innovation. The overall conclusion is that patents are a useful means for measuring environmentally motivated innovations, such as pollution control technologies and green energy technologies, and for general purpose technologies with environmental benefits. For these types of innovations it is acceptable to use patent analysis, provided they are carefully screened. Patent analysis may be used for measuring five attributes of eco-innovation: (1) eco-inventive activities in specific technology fields, (2) international technological diffusion, (3) research and technical capabilities of companies, (4) institutional knowledge sources of eco-innovation, and (5) technological spillovers and knowledge flows. Up until now it is mainly used for measuring eco-inventive activity.Eco-innovation, patents

What Green Economy? Diverse agendas, their tensions and potential futures

The 'green economy' has become a prominent global concept for debating desirable futures, while recasting or marginalising ‘sustainable development’. The dominant agenda promotes state incentives for private-sector solutions through two parallel approaches: A techno-environmental Keynesian agenda attempts to stimulate eco-innovation which can become more resource-efficient and economically competitive. And a green markets agenda seeks to make natural resources more economically visible, as a basis to alleviate poverty. Like sustainable development, green economy agendas claim to redress the socially unequal access to natural resources. These claims have been widely questioned, thus generating extra remedial proposals, opposition and alternative frameworks. The debate features diverse agendas for co-constructing ‘green’ with ‘economy’, especially for assigning economic value to natural resources or environmental burdens. Struggles over potential futures take the form of disputes over defining, allocating and valuing resources – i.e. what counts for a ‘green economy’

A Framework for the Application of Eco-efficiency to the Technology Development Process

The use of technology development process (TDP) models by the enterprises can contribute to the usage control of natural resources of technologies before or after its integration on products, services or processes. Although the choice of a technology can consider the use of some performance metrics to identify their eco-efficiency, the literature about technology development models neglects this element. Based on a qualitative analysis of existing models, this paper proposes a conceptual model for the adoption of eco-efficiency indicators in the TDP by the innovation managers, distributed in three different stages: the initial stage, during the planning of a technology, the intermediate stage, at the technology development, and the final stage, at the technology transfer. Future research, such as prioritizing the indicators and the extent of the present analysis to other sustainability dimensions are suggested for structuring a sustainable model of TDP

From a fossil-fuel to a biobased economy : the politics of industrial biotechnology

Industrial biotechnology involves the replacement of petrochemical processes and inputs with more energy-efficient and renewable biological ones. It is already being used in the production of biofuels and bioplastics and has been touted as a means by which modern economies can be shifted toward a more competitive, low-carbon growth model. This paper does two things. First, it outlines the policy framework established in the European Union and the narrative of a knowledge-based bioeconomy (KBBE) underpinning this. Second, it argues that the ‘win – win’ rhetoric contained within the KBBE narrative is misleading. Among the different groups commenting on the use of industrial biotechnology, the paper locates cleavages between farmers and agribusiness, between those convinced and those sceptical of environmental technofixes, and between procorporate and anticorporate NGOs. Taken together, they show the purported transition from a fossil-fuel to a bio-based economy to be a resolutely political one

Influence of NaNA[3] and CuSO[4] catalytic additives on coal oxidation process kinetic dependencies

Experimental studies of bituminous coal and lignite oxidation were conducted with the addition of different nature catalytic additives: NaNO[3] and CuSO[4]. The results showed that added mineral salts led to a noticeable decrease in the coals initial oxidation temperature and reaction acceleration at an early stage of the process

Innovating Two-Stage Concrete with Improved Rheological, Mechanical and Durability Properties

Two-stage concrete (TSC), also known as preplaced aggregate concrete, is a special type of concrete that is produced using a unique procedure which differs from that of conventional concrete. TSC is distinguished by its high coarse aggregate content and exceptional placement technique, whereby aggregates are first pre-placed in the mold then injected with a special grout. The preplacement of aggregates saves substantial energy since only the grout needs mechanical mixing; the grout is self-leveling and needs no vibration and no mechanical compaction. However, TSC applications are still limited despite substantial advancement of modern concrete technology. Therefore, there is a need to explore new possibilities and applications for TSC through adjusting and improving its properties. The objective of this study is to advance the TSC technology through the use of supplementary cementitious materials (SCMs), fibre reinforcement, capturing its sustainability features to develop novel pavements with very high recycled content, and establishing models with predictive capability for its engineering properties. Therefore, the fresh and hardened properties of grout mixtures incorporating various SCMs, including fly ash (FA), silica fume (SF) and metakaolin (MK) were investigated. An attempt was made to identify the optimum water-to-binder (w/b) ratio and the high-range water-reducing admixture (HRWRA) dosages for grout mixtures that meet the recommended efflux time (i.e. 35-40 ± 2 sec) according to ACI 304.1. Moreover, the effects of various SCMs at different dosages on the development of TSC mechanical properties were investigated. Likewise, the performance of TSC made with single, binary and ternary binders exposed to different environments conducive to physical and chemical sulfate attack was explored. The negative influence of fibres on the workability of conventional concrete is eliminated in TSC since the coarse aggregates and fibres are preplaced in the formwork and then injected with a flowable grout. This allows using fibre dosages beyond the practical levels typically adopted in conventionally mixed concrete. Therefore, the mechanical performance of two-stage steel fibre-reinforced concrete (TSSFRC) made with different dosages of steel fibres having various lengths was explored for the first time. The high coarse aggregate content endows TSC with superior volume stability, making it an ideal contender for pavements and sidewalks, which typically suffer from shrinkage and thermal cracking. In this study, the preplaced material consists of recycled concrete aggregate and scarp tire rubber granules along with scrap tire steel wire fibres, while the grout uses high-volume fly ash. The performance of such a “green” TSC pavement construction technology was explored. Finally, the experimental results were used to create a database which was utilized for developing fuzzy logic (FL) models as a means of predicting the grout flowability (i.e. efflux time and spread flow) and the mechanical properties (i.e. compressive and tensile strength) of a variety of two-stage concrete (TSC) mixtures. Results indicated that grouts made with water-to-binder ratio (w/b) = 0.45 can achieve the recommended grout flowability for successful TSC production. Moreover, TSC grout properties highly depended on the type and dosage of SCM used. The grout flowability was significantly enhanced as the FA dosage was increased, while the compressive strength was decreased. Partially replacing cement with 10% SF or 10% MK reduced the grout flowability and enhanced its compressive strength. Moreover, the binder composition has a great influence on the TSC mechanical properties. Empirical relationships between the properties of the grout and those of the corresponding TSC were proposed, offering a potential tool for estimating TSC properties based on primary grout properties. Furthermore, the ease of using a high dosage of pre-placed fibres in TSSFRC allowed achieving exceptional engineering properties for the pre-placed aggregate concrete. Indeed, TSSFRC can easily be produced with 6% steel fibre dosage, which makes it an innovative option and a strong contender in many construction applications. Fully immersed TSC specimens incorporating FA or MK in sodium sulfate solution exhibited high sulfate resistance. Surprisingly, TSC specimens incorporating SF deteriorated significantly due to thaumasite formation. Under physical sulfate attack exposure, TSC specimens incorporating FA and/or SF incurred severe surface scaling at the evaporative front, while those made with MK exhibited high resistance to surface scaling. A novel eco-efficient technology for the construction of pavements and sidewalks was proposed. The results demonstrate the feasibility of TSC eco-efficient technology to produce durable and cost-effective sidewalks and pavements, offering ease of placement and superior sustainability features. Finally, the performance of the developed FL models was evaluated using error and statistical analyses. The results indicate that the FL models can offer a flexible, adaptable and reasonably accurate tool for predicting the TSC grout flowability and mechanical properties. The findings of this study should provide a leap forward in establishing the TSC technology as a strong contender in many construction applications. It contributes to taking the TSC from a basic technology to a more modern system that benefits from advancements in concrete technology through the use of SCMs, chemical admixtures and fibre reinforcement. In particular, in a new context that values sustainability and “green” construction technology, this study has proven TSC to be exceptional in its ability to use recycled materials without the drawbacks observed in normal concrete technology. These findings should contribute to enhancing the understanding of the TSC behaviour, paving the way for its wider implementation in today’s concrete industry

Post-growth perspectives: Sustainable development based on efficiency and on sufficiency

With the United Nations Sustainable Development Goals (SDGs) and the Paris Agreement the general idea of sustainable development has been transformed into a policy concept with well-defined goals, indicators for measurement and an implementation process. To reduce environmental impact (e.g. on climate, SDG 13) two basic options are available: efficiency and sufficiency. Eco-efficiency (less environmental impact per unit of GDP) still plays the most important role and has the potential to delink economic growth and environmental impact. Growth could continue (green growth). However, rates of efficiency increase are not (yet) large enough to comply with e.g. climate goals – and efficiency increase is (partly) compensated by rebound effects. Therefore, greater emphasis on the sufficiency option (lower GDP) is necessary, i.e. consumption patterns and lifestyles will have to change; in macro-economic terms: economic growth (in rich countries) will have to end. This has significant consequences for the transformation of economies and societies and for government policies, which have been dominated by growth policy. Nevertheless, given the ambitious environmental (climate) goals and the only small effects of efficiency strategies, strengthening of the sufficiency option is inevitable. Only with policy concepts that integrate the efficiency and sufficiency components is there a chance to fulfill environmental SDGs – which are the foundation for many other SDGs