Environmental impact of incineration of calorific industrial waste: Rotary kiln vs. cement kiln

Rotary kiln incinerators and cement kilns are two energy intensive processes, requiring high temperatures that can be obtained by the combustion of fossil fuel. In both processes, fossil fuel is often substituted by high or medium calorific waste to avoid resource depletion and to save costs. Two types of industrial calorific waste streams are considered: automotive shredder residue (ASR) and meat and bone meal (MBM). These waste streams are of current high interest: ASR must be diverted from landfill, while MBM can no longer be used for cattle feeding. The environmental impact of the incineration of these waste streams is assessed and compared for both a rotary kiln and a cement kiln. For this purpose, data from an extensive emission inventory is applied for assessing the environmental impact using two different modeling approaches: one focusing on the impact of the relevant flows to and from the process and its subsystems, the other describing the change of environmental impact in response to these physical flows. Both ways of assessing emphasize different aspects of the considered processes. Attention is paid to assumptions in the methodology that can influence the outcome and conclusions of the assessment. It is concluded that for the incineration of calorific wastes, rotary kilns are generally preferred. Nevertheless, cement kilns show opportunities in improving their environmental impact when substituting their currently used fuels by more clean calorific waste streams, if this improvement is not at the expense of the actual environmental impact.     

RANS-based simulation of transverse turbulent mixing in a 2D geometry

Although transverse mixing is a significant process in river engineering when dealing with the discharge of pollutants from point sources or the mixing of tributary inflows, no theoretical basis exists for the prediction of its rate, which is indeed based upon the results of experimental works carried on in laboratory channels or in streams and rivers. The paper presents the preliminary results of a numerical study undertaken to simulate the transverse mixing of a steady-state point source of a tracer in a two-dimensional rectangular geometry, which is expected to reproduce a shallow flow. This geometry is that of Lau and Krishnappan (J Hydraul Div 13(HY10):1173–1189, 1977), who collected turbulent mixing data for a shallow flow. In the numerical study an approach based on the Reynolds Averaged Navier–Stokes (RANS) equations was applied, where the closure problem was solved by using turbulent viscosity concept. Particularly, the classical two-equations k–? model was used. Two methods were applied to the model results to evaluate the turbulent transverse mixing coefficient. The effect on transverse mixing of a grid located upstream the tracer source was also studied. Numerical results were generally higher than the experimental data. This overestimation could be explained considering the hypothesis of isotropic turbulence underlying the k–? model, which can lead to large turbulent viscosities and rate of mixing. However, RANS-based results may still be considered acceptable also providing the large uncertainties associated with literature predictive equations.     

Opportunities and challenges for Common Agricultural Policy reform to support the European Green Deal

The Common Agricultural Policy (CAP) is the European Union's main instrument for agricultural planning, with a new reform approved for 2023–2027. The CAP intends to align with the European Green Deal (EGD), a set of policy initiatives underpinning sustainable development and climate neutrality in the European Union (EU), but several flaws cast doubts about the compatibility of the objectives of these 2 policies. We reviewed recent literature on the potential of CAP environmental objectives for integration with the EGD: protection of biodiversity, climate change mitigation and adaptation, and sustainable management of natural resources. The CAP lacks appropriate planning measures, furthering instead risks to biodiversity and ecosystem services driven by landscape and biotic homogenization. Funding allocation mechanisms are not tailored to mitigate agricultural emissions, decreasing the efficiency of climate mitigation actions. The legislation subsidies farmers making extensive use of synthetic inputs without adequately supporting organic production, hindering the transition toward sustainable practices. We recommend proper control mechanisms be introduced in CAP Strategic Plans from each member state to ensure the EU is set on a sustainable production and consumption path. These include proportional assignment of funds to each CAP objective, quantitative targets to set goals and evidence-based interventions, and relevant indicators to facilitate effective monitoring of environmental performance. Both the CAP and the EGD should maintain ambitious environmental commitments in the face of crisis to avoid further degradation of the natural resources on which production systems stand.     

Oxidative degradation of chlorophenol derivatives promoted by microwaves or power ultrasound: a mechanism investigation

Background, aim, and scope

Phenols are the most common pollutants in industrial wastewaters (particularly from oil refineries, resin manufacture, and coal processing). In the last two decades, it has become common knowledge that they can be effectively destroyed by nonconventional techniques such as power ultrasound (US) and/or microwave (MW) irradiation. Both techniques may strongly promote advanced oxidation processes (AOPs). The present study aimed to shed light on the effect and mechanism of US- and MW-promoted oxidative degradation of chlorophenols; 2,4-dichlorophenoxyacetic acid (2,4-D), a pesticide widespread in the environment, was chosen as the model compound.

Materials and methods

2,4-D degradation by AOPs was carried out either under US (20 and 300 kHz) in aqueous solutions (with and without the addition of Fenton reagent) or solvent-free under MW with sodium percarbonate (SPC). All these reactions were monitored by gas chromatography–mass spectrometry (GC–MS) analysis and compared with the classical Fenton reaction in water under magnetic stirring. The same set of treatments was also applied to 2,4-dichlorophenol (2,4-DCP) and phenol, the first two products that occur a step down in the degradation sequence. Fenton and Fenton-like reagents were employed at the lowest active concentration.

Results

The effects of US and MW irradiation were investigated and compared with those of conventional treatments. Detailed mechanisms of Fenton-type reactions were suggested for 2,4-D, 2,4-DCP, and phenol, underlining the principal degradation products identified. MW-promoted degradation under solvent-free conditions with solid Fenton-like reagents (viz. SPC) is extremely efficient and mainly follows pyrolytic pathways. Power US strongly accelerates the degradation of 2,4-D in water through a rapid generation of highly reactive radicals; it does not lead to the formation of more toxic dimers.

Discussion

We show that US and MW enhance the oxidative degradation of 2,4-D and that a considerable saving of oxidants and cutting down of reaction times is thereby achieved. The results support the interpretation of previously published data and improve the understanding of the factors of direct degradation along different pathways.

Conclusions

Oxidative pathways for 2,4-D, 2,4-DCP, and phenol were proposed by a careful monitoring of the reactions and detection of intermediates by GC–MS.

Recommendations and perspectives

The understanding of the factors that affect chlorophenols degradation along different pathways may facilitate the optimization of the treatment. Type of energy source (US or MW), power, and frequency to be applied could be designed in function of the operative scenario (amount of pollutant in soil, water, or oils).     

Village pubs as a social propellant in rural areas: an econometric study

There is no place like England to witness the role of pubs as a social networking hotspot. Social networks lie at the foundations of most of the social and economic interactions of individuals. The aim of this paper is to assess the importance of pubs as natural locations for the development of social networks and how their presence affects the socio-economic activity of a given area or region. The econometric analysis conducted on rural parishes in Cumbria, a peripheral county in Northern England, reveals that village pubs have a positive influence on the socio-economic activity of local communities.     

Climate hotspots: key vulnerable regions,climate change and limits to warming

This paper reviews scientific and gray literature addressing climate change vulnerability and adaptation in the Inuvialuit Settlement Region (ISR) in the western Canadian Arctic. The review is structured using a vulnerability framework, and 420 documents related directly or indirectly to climate change are analyzed to provide insights on the current state of knowledge on climate change vulnerability in the ISR as a basis for supporting future research and long-term adaptation planning in the region. The literature documents evidence of climate change in the ISR which is compromising food security and health status, limiting transportation access and travel routes to hunting grounds, and damaging municipal infrastructure. Adaptations are being employed to manage changing conditions; however, many of the adaptations being undertaken are short term, ad-hoc, and reactive in nature. Limited long-term strategic planning for climate change is being undertaken. Current climate change risks are expected to continue in the future with further implications for communities but less is known about the adaptive capacity of communities. This review identifies the importance of targeted vulnerability research that works closely with community members and decision makers to understand the interactions between current and projected climate change and the factors which condition vulnerability and influence adaptation. Research gaps are identified, and recommendations for advancing adaptation planning are outlined.     

Recovery of MSWI and soil washing residues as concrete aggregates

The aim of the present work was to study if municipal solid waste incinerator (MSWI) residues and aggregates derived from contaminated soil washing could be used as alternative aggregates for concrete production.Initially, chemical, physical and geometric characteristics (according to UNI EN 12620) of municipal solid waste incineration bottom ashes and some contaminated soils were evaluated; moreover, the pollutants release was evaluated by means of leaching tests. The results showed that the reuse of pre-treated MSWI bottom ash and washed soil is possible, either from technical or environmental point of view, while it is not possible for the raw wastes.Then, the natural aggregate was partially and totally replaced with these recycled aggregates for the production of concrete mixtures that were characterized by conventional mechanical and leaching tests. Good results were obtained using the same dosage of a high resistance cement (42.5R calcareous Portland cement instead of 32.5R); the concrete mixture containing 400 kg/m³ of washed bottom ash and high resistance cement was classified as structural concrete (C25/30 class). Regarding the pollutants leaching, all concrete mixtures respected the limit values according to the Italian regulation.     

Comparative study of the urban quality of life in Cuban first-level cities from an objective dimension

The urban quality of life (UQoL) from objective dimension was analyzed in the main Cuban cities. An Urban Quality of Life Index (UQoLI) was developed in collaboration with 60 experts (five in each city). These experts belong to one of two categories: in charge of the planning of the city and members of the Municipal Council of Administration. One hundred and forty-two directors of the Local District Administration also participated in the analysis. The UQoLI includes three dimensions: social services, economic performance, and urban services, the importance of which is weighed according to expert criteria. A Ranking of the studied cities, sorted by the UQoLI, shows a tendency of increase it UQoL in the west even and central regions. This tendency contradicts one of the foundations of the Cuban sustainable development framework, i.e., equity.     

Cardiac flow after fetal blood sampling in normally grown and growth-retarded fetuses

The objective of this study was to evaluate the effect of fetal blood sampling on cardiac flow velocity waveforms. Flow velocity waveforms were measured from the ascending aorta and pulmonary artery immediately before and after fetal blood sampling in 29 normally grown and 12 growth-retarded fetuses. The latter group was characterized by abnormal Doppler indices in the umbilical artery and middle cerebral artery suggestive of uteroplacental insufficiency as the causative factor of the impaired growth. The flow velocity parameters studied were the peak velocity, the time to peak velocity, and the left and right cardiac output and their ratio. In normally grown fetuses, the peak velocity and right and left cardiac output values increased significantly after fetal blood sampling, while no significant changes were observed in the other indices considered. The gestational age at the time of the procedure was positively related to the amplitude of these changes. In growth-retarded fetuses, fetal blood sampling did not induce any significant increase in cardiac output or peak velocities, while in more than 50 per cent of the fetuses these Doppler indices decreased. The amplitude of the decrease was significantly related to the severity of acidosis in the umbilical vein. In conclusion, the cardiac haemodynamic response to fetal blood sampling differs between normally grown and growth-retarded fetuses. This difference may explain the higher rate of complications occurring in the latter group of fetuses after blood sampling.