Improving rapeseed carbon footprint evaluation via the integration of remote sensing technology into an LCA approach.

Agricultural carbon footprint (CF) evaluation plays an important role in climate change mitigation and national food security. Many studies have been conducted worldwide to evaluate the CF of rapeseed and its byproducts; however, only a few of these studies have considered finer-scale spatial-temporal heterogeneity. Considering the advantages of using detailed crop information extracted by remote sensing (RS) techniques, we attempted to integrate RS into life cycle assessments to improve rapeseed CF evaluation. A case study was conducted from 2021 to 2023 in one of the most important grain- and rapeseed-producing areas in Southwest China, namely, the Chengdu Plain, covering an area of 18,810.00 km2. The results of our study suggest that: (1) the proposed approach is applicable for high-resolution (10 m ∗ 10 m) rapeseed distribution mapping; (2) the farm-based CFs of rapeseed in the studied region range from 3333.08 to 4572.82 kgCO2-eq ha-1, while the product-based CFs (PCFs) vary from 1316.23 to 2443.95 kgCO2-eq t-1. Nitrogen fertilizer processing and its application are identified as the dominant contributors to upstream and downstream greenhouse emissions (GHGs), respectively; (3) the significant role of soil properties and soil organic carbon in influencing crop PCFs indicates good GHG offsets. The method used in the current study has strong adaptability and universality in different areas with various climatic conditions and can provide a solid basis for policymakers to formulate differentiated agricultural carbon reduction policies.

How to identify suitable ways for the hydrothermal treatment of wet bio-waste? A critical review and methods proposal.

A considerable amount of wet biogenic residues and waste has no resource-efficient use in several European countries yet. Hydrothermal processes (HTP) seem to be promising for treating such biomass as they best work with substrates with 70% to 90% water content. However, thus far the suitability of HTP for this purpose has not been sufficiently evaluated, for which this work aims to identify suitable multi-criteria analysis (MCA) methods that can be used to identify promising ways for the hydrothermal treatment of wet bio-waste. A review on 31 recent MCA studies in bio-waste management was conducted with the aim of comparing them to methodological requirements for evaluating HTP. Furthermore, an MCA approach for HTP based on the review findings is proposed. Results show that no observed MCA method is directly transferable for assessing HTP, for which a customized approach combining the analytical hierarchy process and the technique for order preference by similarity to ideal solutions is proposed and preliminarily validated with literature data. These preliminary calculations indicate that hydrothermal gasification seems most promising under consideration of multiple criteria using the available average and exemplary data. However, needless to say there is still a long way to go to obtain the sufficient adequate data to validate and use the model appropriately, for which further studies are necessary to acquire more reliable data and to assess also future technology developments of HTP.

A systems dynamics approach for supporting regional decisions on the energetic use of regional biomass residues.

This article presents the definition, building, calibration and application of a system dynamics simulation model to quantify the present and future comparative advantages and disadvantages of using forest and agricultural residual biomass for energetic purpose through different processes and technologies, on a regional basis. A dynamic structure of the agricultural and forestry biomass process activities (i.e. production, transport, conversion and consumption) based on regional time-series data was built, implemented into and calibrated within a dynamic simulation tool (Vensim software) within a Hungarian county. Besides the agriculture and forestry sectors, the model includes data about demography, economy, environment and land use, among others. For carrying out the assessment, realistic scenarios of future biomass processes and of biomass use were formulated, characterised by quantitative sustainable development indicators and simulated within the dynamic model. The results prove that the introduced model supports decision making of biomass utilisation in a regional scale, through comparing and analysing quantitative changes of economic, social and environment indicators, which characterise a sustainable regional development. The model therefore allows analyses and evaluation of not only partial prosperous or adverse characteristics of biomass processes and use, but also to relate regional components and their development over time. The developed dynamic tool is therefore a powerful method to model complex systems, such as a regional energy system, considering the framework of the regional preferences stated by the regional stakeholders. It can thus provide useful decision support, especially when used as a priority-based screening of potential regional development programmes in the energy field.

Cascade use indicators for selected biopolymers: Are we aiming for the right solutions in the design for recycling of bio-based polymers?

When surveying the trends and criteria for the design for recycling (DfR) of bio-based polymers, priorities appear to lie in energy recovery at the end of the product life of durable products, such as bio-based thermosets. Non-durable products made of thermoplastic polymers exhibit good properties for material recycling. The latter commonly enjoy growing material recycling quotas in countries that enforce a landfill ban. Quantitative and qualitative indicators are needed for characterizing progress in the development towards more recycling friendly bio-based polymers. This would enable the deficits in recycling bio-based plastics to be tracked and improved. The aim of this paper is to analyse the trends in the DfR of bio-based polymers and the constraints posed by the recycling infrastructure on plastic polymers from a systems perspective. This analysis produces recommendations on how life cycle assessment indicators can be introduced into the dialogue between designers and recyclers in order to promote DfR principles to enhance the cascading use of bio-based polymers within the bioeconomy, and to meet circular economy goals.

Life cycle comparison of waste-to-energy alternatives for municipal waste treatment in Chilean Patagonia.

The energy system in the Region of Aysén, Chile, is characterized by a strong dependence on fossil fuels, which account for up to 51% of the installed capacity. Although the implementation of waste-to-energy concepts in municipal waste management systems could support the establishment of a more fossil-independent energy system for the region, previous studies have concluded that energy recovery systems are not suitable from an economic perspective in Chile. Therefore, this work intends to evaluate these technical options from an environmental perspective, using life cycle assessment as a tool for a comparative analysis, considering Coyhaique city as a case study. Three technical alternatives were evaluated: (i) landfill gas recovery and flaring without energy recovery; (ii) landfill gas recovery and energy use; and (iii) the implementation of an anaerobic digestion system for the organic waste fraction coupled with energy recovery from the biogas produced. Mass and energy balances of the three analyzed alternatives have been modeled. The comparative LCA considered global warming potential, abiotic depletion and ozone layer depletion as impact categories, as well as required raw energy and produced energy as comparative regional-specific indicators. According to the results, the use of the recovered landfill gas as an energy source can be identified as the most environmentally appropriate solution for Coyhaique, especially when taking into consideration the global impact categories.

Assessment and optimization of an ultrasound-assisted washing process using organic solvents for polychlorinated biphenyl-contaminated soil.

The goal of this work was to evaluate a washing process that uses organic solutions for polychlorinated biphenyl (PCB)-contaminated soil, and includes an ultrasound pre-treatment step to reduce operational times and organic solvent losses. In a preliminary trial, the suitability of 10 washing solutions of different polarities were tested, from which three n-hexane-based solutions were selected for further evaluation. A second set of experiments was designed using a three-level Taguchi L27 orthogonal array to model the desorption processes of seven different PCB congeners in terms of the variability of their PCB concentration levels, polarity of the washing solution, sonication time, the ratio washing solution/soil, number of extraction steps and total washing time. Linear models were developed for the desorption processes of all congeners. These models provide a good fit with the results obtained. Moreover, statistically significant outcomes were achieved from the analysis of variance tests carried out. It was determined that sonication time and ratio of washing solution/soil were the most influential process parameters. For this reason they were studied in a third set of experiments, constructed as a full factorial design. The process was eventually optimized, achieving desorption rates of more than 90% for all congeners, thus obtaining concentrations lower than 5 ppb in all cases. The use of an ultrasound-assisted soil washing process for PCB-contaminated soils that uses organic solvents seems therefore to be a viable option, especially with the incorporation of an extra step in the sonication process relating to temperature control, which is intended to prevent the loss of the lighter congeners.

Hazardous waste management in Chilean main industry: an overview.

The new "Hazardous Waste Management Regulation" was published in the Official Newspaper of the Chilean Republic on 12 June 2003, being in force 365 days after its publication (i.e., 12 June 2004). During the next 180 days after its publication (i.e., until 12 December 2004), each industrial facility was obligated to present a "Hazardous Waste Management Plan" if the facility generates more than 12 ton/year hazardous wastes or more than 12 kg/year acute toxic wastes. Based on the Chilean industrial figures and this new regulation, hazardous waste management plans were carried out in three facilities of the most important sectors of Chilean industrial activity: a paper production plant, a Zn and Pb mine and a sawmill and wood remanufacturing facility. Hazardous wastes were identified, classified and quantified in all facilities. Used oil and oil-contaminated materials were determined to be the most important hazardous wastes generated. Minimization measures were implemented and re-use and recycling options were analyzed. The use of used oil as alternative fuel in high energy demanding facilities (i.e., cement facilities) and the re-refining of the used oil were found to be the most suitable options. In the Zn and Pb mine facility, the most important measure was the beginning of the study for using spent oils as raw material for the production of the explosives used for metals recovery from the rock. In Chile, there are three facilities producing alternative fuels from used oil, while two plants are nowadays re-refining oil to recycle it as hydraulic fluid in industry. In this sense, a proper and sustainable management of the used oil appears to be promissory.

Remediation technologies for organochlorine-contaminated sites in developing countries.

Despite its importance in human life, until recently the relationship between soils and human health has been undervalued, especially in least developed countries. Currently, a holistic approach has been incorporated to identify best practices in soil science, defining it as "the task of all people concerned with the soil to direct their interest, not just towards the physical, chemical, and biological aspects, but also to those environmental, economic, social, legal, and technical aspects that affect soil use" (Abrahams 2002; Fent 2003). Considering this definition, the European Union (EU) as well as most developed countries have recognized organochlorine-contaminated sites as potential threats to the human health, threats that take different forms, such as their influence on water (e.g., drinking water resources), soil, and air as well as their interrelationships, which can directly affect human health (EC 2002; EP 2002; Bezama et al. 2004). Moreover, economic expansion and industrial growth are linked with growing lack of "greenfields" (a term that defines all areas without previous history of development): the supply of new building sites is limited and must contend with other competing uses, such as housing, recreation, nature, traffic, or agriculture (De Sousa 2001; Tedd et al. 2001). Thus, cleaning and reusing contaminated sites can be a meaningful alternative to address this issue, because most contaminated sites are located in metropolitan centres and are, therefore, prime candidates for urban development (Lorber et al. 2004).

Land register of contaminated sites in an industrial Chilean region: identification and evaluation of suspected sites.

This work introduces the outcomes of the first process for the identification and evaluation of sites potentially contaminated in the Region of the Bio Bio, Chile. The methodology combined qualitative and quantitative elements from Austrian and German risk assessment procedures, calibrated and adapted to the Chilean reality. The developed process consists of collecting historical and current registers on soil use, effects of materials handling on the population's health, and the description of the site conditions. The first analytical step corresponds to an image algebra analysis, through which the most vulnerable areas of the region are established. The sites identified inside the most vulnerable areas are classified into five priority classes, giving an approximate degree of endangerment from these sites. Through the experience, from a total of 507 sites identified as suspicious of contamination, five sites were classified under the highest priority. The results of this analysis have allowed Chilean authorities to focus their resources on the detailed investigations to be carried out in the five priority locations, whilst planning the future strategy to follow for the practical management of all sites found as currently posing a risk to the environment and to the society.

Lessons learned for a more efficient knowledge and technology transfer to South American countries in the fields of solid waste and contaminated sites management.

The present paper describes the development, performance and conclusions derived from three know-how and technology transfer projects to South American countries. The first project comprised a collaborative study by European and South American universities to find sustainable solutions for Chilean and Ecuadorian leather tanneries which had underachieving process performances. The second project consisted of investigations carried out in a Brazilian municipality to enhance its municipal solid waste management system. The final collaborative programme dealt with the initial identification, evaluation and registration of suspected contaminated sites in an industrial region of Chile. The detailed objectives, methods and procedures applied as well as the results and conclusions obtained in each of the three mentioned projects are presented, giving special attention to the organizational aspects and to the practical approach of each programme, concluding with their main advantages and disadvantages for identifying a set of qualitative and quantitative suggestions, and to establish transferable methods for future applications.

Investigations on mechanical biological treatment of waste in South America: towards more sustainable MSW management strategies.

This work presents an analysis on the suitability of mechanical biological treatment of municipal solid waste in South America, based on two previous experimental investigations carried out in two different countries. The first experiment was performed for determining the mass and volume reduction of MSW in the province of Concepción (Chile). The implemented bench-scale process consisted of a manual classification and separation stage, followed by an in-vessel biological degradation process. The second experiment consisted of a full-scale experiment performed in the city of Estrela (Brazil), where the existing municipal waste management facility was adapted to enhance the materials sorting and separation. Expressed in wet weight composition, 85.5% of the material input in the first experiment was separated for biological degradation. After 27 days of processing, 60% of the initial mass was reduced through degradation and water evaporation. The final fraction destined for landfilling equals 59% of the total input mass, corresponding to about 50% of the initial volume. In the second experiment, the fraction destined to landfill reaches 46.6% of the total input waste mass, whilst also significantly reducing the total volume to be disposed. These results, and the possible recovery of material streams suitable for recycling or for preparing solid recovered fuels, are the main advantages of the studied process.