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Cement production has advanced greatly in the last few decades. The traditional fuels used in traditional kilns include coal, oil, petroleum coke, and natural gas. Energy costs and environmental concerns have encouraged cement companies worldwide to evaluate to what extent conventional fuels can be replaced by waste materials, such as waste oils, mixtures of non-recycled plastics and paper, used tires, biomass wastes, and even wastewater sludge. The paper aims to discuss these issues.

The work is based on literature review.

The clinker firing process is well suited for various alternative fuels (AF); the goal is to optimize process control and alternative fuel consumption while maintaining clinker product quality. The potential is enormous since the global cement industry produces about 3.5 billion tons that consume nearly 350 million tons of coal-equivalent fossil and AF. This study has shown that several cement plants have replaced part of the fossil fuel used by AF, such waste recovered fuels. Many years of industrial experience have shown that the use of wastes as AF by cement plants is both ecologically and economically justified.

The substitution of fossil fuels by AF in the production of cement clinker is of great importance both for cement producers and for society because it conserves fossil fuel reserves and, in the case of biogenic wastes, reduces greenhouse gas emissions. In addition, the use of AF can help to reduce the costs of cement production.

The purpose of this paper is to determine the production and energy potential of refuse derived fuel (RDF) in Latvia, in order to understand how large an impact municipal waste incineration with energy recovery has on waste management and energy supply systems in Latvia.

The results of the study are based on historical data of municipal solid waste (MSW) management. The potential of RDF in Latvia is estimated and future sources of RDF production until 2020 are projected. The calculations of RDF potential are based on data on MSW generation, landfilling and composition, and on the calorific value of RDF fractions. The study also takes into account experimental results of RDF production trials in one landfill in Latvia.

The amount of MSW landfilled annually until 2020 will grow, therefore new waste management options will have to be found in order to comply with EU waste policy. One of the options is waste‐to‐energy. The energy amount potentially produced by incinerating RDF made of MSW in Latvia could account for approximately 2 per cent of the total energy amount produced in 2010, if the RDF conversion rate is assumed to be 30per cent, and up to 3.5 per cent – if the RDF conversion rate is 50 per cent.

There are just a few studies analysing RDF potential for a certain region (in this case – country). There is a lack of data and official projections of generated waste amounts which are typical for Latvia, therefore no detailed assessments are available on how much energy it would be possible to produce from the waste generated in Latvia. In this paper, the RDF production potential itself, as well as the energy potential produced via RDF in Latvia, is assessed. In order to estimate future availability of resources for RDF production, future MSW generation and landfilling amounts in Latvia until 2020 are projected.

This paper seeks to focus on energy recovery from municipal solid waste (MSW) in Croatia. The state strategy is based on the mechanical and biological treatment of waste in the future waste management centers (WMC). Left over after the treatment is waste that can be used as fuel (e.g. RDF).

Starting from the geographical distribution of waste generation (quantities and transport distances), taking into account the costs of collection, transfer and thermal treatment, recommendations on optimal number and size of the dedicated waste‐to‐energy (WtE) plants in Croatia as well as their potential locations are given. The opportunity of the cement industry to utilize ash from thermal treatment of waste in the process of the cement production and the RDF as a substitute fuel is also examined.

By varying the number of WMCs, the minimal specific cost of waste collection of €33 is obtained, for maximal number of WMCs, which is 21. The optimal capacity of WtE facility is approximately 300,000 t/year, for expected quantity of 600,000 t/year of waste available for energy recovery. However, the geographical shape of Croatia and traffic connections suggest that its area could be better covered by four WtE facilities, each with the capacity of 150,000 t/year. The alternative solution could include the existing cement industry. In this case one bigger WtE plant (preferably near the city of Zagreb) could be built, with the capacity of 400,000 t/year, while the rest of the waste would be used in the cement industry, which capacity amounts to 167,000 tons of RDF annually.

This analysis gives another view of a possible system for energy recovery from MSW in Croatia. MSW has never been used in Croatia for the purpose of energy generation on a wider scale.

This paper aims to present the production of waste plastic oil from landfill waste plastics, the performance and emissions of a compression ignition (CI) engine, using waste plastic oil, were tested and compared with using diesel oil. The physical characteristics, gross calorific value (MJ/kg), kinematic viscosity cst @40°C, specific gravity @15.6°C, cetane index, flash point and distillation temperature @90 per cent are determined. The experimental CI engine is a four-stroke, direct injection, single cylinder, 709 C.C. and has been tested with in-brake-specific fuel consumption (BSFC), brake conversion efficiency, brake-specific energy consumption and exhaust gas emissions.

The results show that the characteristics of liquid fuel from landfill plastics (LFLP3) are similar to diesel oil. The CI engine was able to run with LFLP3. The efficiency was slightly higher than that of diesel fuel, whereas the BSFC was lower. The exhaust-gas emission average for LFLP3 was reduced compared to diesel oil operation.

The efficiency of the CI engine using LFLP3 is slightly higher than diesel fuel at all load conditions. In this study, LFLP3 was a lower pollutant than diesel fuel. Environmental values and energy consumption are important when reviewing the ignition of any fuel in a combustion chamber.

The efficiency of the CI engine using LFLP3 is slightly higher than diesel fuel at all load conditions. In this study, LFLP3 was a lower pollutant than diesel fuel. Environmental values and energy consumption are important when reviewing the ignition of any fuel in a combustion chamber.

In a new build waste incinerator, the waste (refuse derived fuel) was burned on a discontinuous moving grate. Frequent furnace overpressure peaks occurred because of this firing method and as a result, flue gas and fly‐ash were pushed out of the boiler and into the building. During the plant start up period, a seal in a water‐feed pipeline broke, and a large amount of condensed steam was discharged into the boiler house. Shortly thereafter, very severe corrosion was noticed on the galvanised gangways, steel building components, the boiler aluminium sheeting and on processing lines. A theoretical study of the condensation of the flue gas indicated that sulphuric acid would condense before it reached the external aluminium sheeting and that under normal conditions, dry hydrochloric acid fumes would be removed by the boiler house ventilators. However, the steam leakage had caused the hydrochloric acid to be dissolved in the condensed water and that had resulted in the severe corrosion damage, which had become evident subsequently.

Circular economy (CE) disclosure is becoming urgent for firms, but an accepted and recognized approach to address it is still missing, especially at small and medium enterprises (SMEs) level. This study aims to contribute to this issue by exploring the potential of the adoption of Global Reporting Initiative (GRI) Standards as a standardized approach for CE disclosure. The paper proposes a framework that identifies the existence of specific relationships between the topics included in GRI 300 Standards and CE strategies, which can be considered as managerial guidelines for CE strategy disclosure by companies.

The paper uses an explorative research methodology based on the content analysis of secondary data taken from the sustainability reports of the SMEs listed in STAR segment of Borsa Italiana.

The analysis shows that GRI Standards are currently adopted to disclose the CE strategies by Italian SMEs across different economic sectors including construction, food, automotive, retail, personal and household goods, industrial goods and services, electronics, media and technology. In particular, GRI 301 is used for the disclosure about Recycling, Reuse, Reverse logistics, Industrial Symbiosis, Eco-Design, Product as a Service and Refurbishing/Reconditioning/Remanufacturing. GRI 302 is suited to disclose CE strategies about Eco-Design, Renewable Energy and Industrial Symbiosis. GRI 303 can be useful to disclose about Reuse and Industrial Symbiosis. GRI 305 is appropriate for Eco-Design, Renewable Energy, Product as a Service, Industrial Symbiosis and Recycling. Finally, GRI 306 is useful to communicate the CE strategies of Recycling, Reuse, Reverse Logistics, Eco-Design, Industrial Symbiosis, Maintenance/Repair, Refurbishing/Reconditioning/Remanufacturing.

The paper includes implications concerning how to report the implementation of a wide range of CE practices, mainly using GRI 301, 302, 303, 305 and 306. These implications are mainly addressed to SMEs in different economic sectors.

The use of the proposed framework, by improving the transparency and communication of the CE strategies used by companies, may contribute to accelerate the consumer awareness on CE practices fostering the CE transition, especially of SMEs, with a positive effect on society and environment.

This study extends the literature on CE by developing one among the few standardized approaches using the GRI Standards for the disclosure of CE strategies, a topic mainly investigated in the literature with reference to large companies in a few industries. The framework is also useful to explore the implementation of CE strategies across SMEs in different industrial sectors.

This paper examines future trends in the environment and clean technologies (ECT) sector. Seven national technology foresight studies have been reviewed with the purpose of (i) screening the main issues linked to environmental and clean technologies (ii) highlighting major developments that are likely to play a crucial role for future paths towards sustainability.

The purpose of this study is to assess the performance of fuel blends containing ethanol and gasoline in spark ignition engines. The aim is to explore alternative fuels that can enhance performance while minimizing or eliminating adverse environmental impacts, particularly in the context of limited fossil fuel availability and the need for sustainable alternatives.

The authors used the Ricardo Wave software to evaluate the performance of fuel blends with varying ethanol content (represented as E0, E10, E25, E40, E55, E70, E85 and E100) in comparison to gasoline. The assessment involved different composition percentages and was conducted at various engine speeds (1,500, 3,000, 4,500 and 6,000 rpm). This methodology aims to provide a comprehensive understanding of how different ethanol-gasoline blends perform under different conditions.

The study found that, across all fuel blends, the highest brake power (BP) and the highest brake-specific fuel consumption (BSFC) were observed at 6,000 rpm. Additionally, it was noted that the presence of ethanol in gasoline fuel blends has the potential to increase both the BP and BSFC. These findings suggest that ethanol can positively impact the performance of spark-ignition engines, highlighting its potential as an alternative fuel.

This research contributes to the ongoing efforts in the automotive industry to find sustainable alternative fuels. The use of Ricardo Wave software for performance assessment and the comprehensive exploration of various ethanol-gasoline blends at different engine speeds add to the originality of the study. The emphasis on the potential of ethanol to enhance engine performance provides valuable insights for motor vehicle manufacturers and researchers working on alternative fuel solutions.

The chief reason for disciplinary action against blue collar workers is poor timekeeping, followed by unauthorised absence and poor work standards, says a report from the Institute of Personnel Management.

Important differentiating attributes in the procedures used, the characteristic mineral composition of the binders, and the implications these have on the final long term stability and physico-mechanical performance of the concretes produced are identified and discussed, with the intent to improve transparency and clarity in the field of geopolymer concrete technologies.

This state-of-the-art review covers the area of geopolymer concrete, a class of sustainable construction materials that use a variety of alternative powders in lieu of cement for composing concrete, most being a combination of industrial by-products and natural resources rich in specific required minerals. It explores extensively the available essential materials for geopolymer concrete and provides a deeper understanding of its underlying chemical mechanisms.

This is a state-of-the-art review introducing the essential characteristics of alternative powders used in geopolymer binders and the effectiveness these have on material performance.

With the increase of need for alternative cementitious materials, identifying and understanding the critical material components and the effect they may have on the performance of the resulting mixes in fresh as well as hardened state become a critical requirement to for short- and long-term quality control (e.g. flash setting, efflorescence, etc.).

The topic explored is significant in the field of sustainable concrete technologies where there are several parallel but distinct material technologies being developed, such as geopolymer concrete and alkali-activated concrete. Behavioral aspects and results are not directly transferable between the two fields of cementitious materials development, and these differences are explored and detailed in the present study.