Application of multi-criteria decision-making tools for assessing biogas plants: a case study in Reykjavik, Iceland

The European Union is planning a new program to achieve climate neutrality by 2050. In this context, the Icelandic government plans to ban new registrations of fossil fuel cars after 2030 as one of the strategies to make Iceland a carbon-neutral country by 2040. Upgraded biogas can be directly used in vehicles with CNG engines, reducing CO2 emissions by 80%. In this paper, several alternatives of biogas plants, simulated in previous research, were evaluated by considering techno-economic and environmental criteria through the application of multi-criteria decision-making tools. Twelve alternatives were analyzed using the Definite 3.1 software. A weighted summation algorithm, which transforms all criteria into the same scale by multiplying them by weights and then summing them to obtain the results, was used in the analysis. The multi-criteria analysis of the twelve proposed alternatives included eleven criteria (three technical, five economic, and three environmental) whose weights were changed in a total of eleven scenarios. From a global perspective, when all criteria were considered (9.1% weight) the best alternative with a score of 0.58 was the single-stage biogas plant working with municipal solid waste. Sensitivity and uncertainty analyses also demonstrated that the multi-criteria results obtained were robust and reliable.The APC was paid by the COST Action CA17133 Circular City (“Implementing naturebased solutions for creating a resourceful circular city”, http://www.circular-city.eu, duration 22 October 2018–21 October 2022)

Multi-criteria analysis of detoxification alternatives: techno-economic and socio-environmental assessment

The transformation of fermentable sugars provided from lignocellulosic wastes into biofuels or bioproducts is a key point at second-generation biorefineries. Spent sulfite liquor is a xylose-rich hydrolysate constituting the main residue of sulfite mills producing dissolving cellulose. Due to the presence of the inhibitors in the spent liquor, the most promising valorization options require detoxification before sugars bioconversion. In this work, a multi criteria analysis was implemented to select techno-economic and socio-environmental feasible detoxification alternatives that can be adapted to a wide variety of fermenting scenarios. Total inhibitors removal, phenolics removal, acetic acid removal, lignosulfonates removal, total sugar losses, fixed capital invested, manufacturing costs, waste toxicity, social acceptance, and employment were chosen as the most relevant criteria. The maximum allowable concentration of undesirable inhibitors cannot be established with a general character, and thereby decision-making tools result in feasible and efficient solutions. From a technical viewpoint best solution was anionic resins with a score of 0.68; the most economical alternative was the overliming with a score of 0.76; finally, from a socio-environmental perspective, overliming reached the highest score of 0.78. In addition, three spent liquor biorefinery models were proposed. Based on the multicriteria analysis and based on the inhibitor?s concentration affecting fermentation yields and productivity, the best detoxification alternatives were (1) anionic resins for polyhydroxyalkanoate production; (2) activated carbon for ethanol biorefinery; (3) overliming for xylitol biorefinery.The authors gratefully acknowledge the financial support by KBBE-2012-6-311935 BRIGIT research project www.brigit-project.e

Waste indicators of primary sector and health & veterinary services for regional planning

When there is a need to move smoothly and effectively from an abundance of detailed field data to summarized information, indicators and indices are used. Indicators are important tools that assist decision-makers in formulating and implementing plans for the management of waste at different geographic levels. In Cantabria, a northern Spanish region, all waste streams generated are covered through four specific Waste Plans recently adopted. The present study is focused on the Primary Sector, Health & Veterinary Services Waste Plan (PHWP), which is the framework to the decision-making processes related to the generation and management of forest, agricultural, livestock, food industry and health & veterinary wastes. In this work, 16 indicators have been proposed to track the evolution over time of the management of these waste streams in the region and the degree of achievement of the policy objectives. This article discusses the way to obtain, analyse and evaluate valuable information to build the indicators, finding that only eight indicators can be applied at short term. In addition, a summary of these indicators is included, showing in general, a good trend of the evolution of primary sector, health & veterinary waste management. Finally, different actions to improve the quality of data used for the indicators development are proposed in order to obtain more useful waste indicators to the stakeholders

Primary sector waste indicators for regional planning

Decisions are made based on information of different kinds and several tools have been developed to facilite the inclusion of environmental aspects in decision-making. One of these tools is the indicators that have become a vital component of environmental impact assessments and "state of the environmental" reporting. In Cantabria, a northern Spanish region, a specific set of indicators has been developed to monitor the degree of implementation of waste policies recently adopted in the region, identified in the Cantabria Regional Waste Plan 2010- 2014. This Regional Planning covers all waste streams generated: There is a Regional Waste Plan developed through four Sectorial Waste Plans on: (i) Primary Sector and Sanitary Waste; (ii) Industrial, Construction and Demolition, and Mining Waste; (iii) Special Waste, and (iv) Municipal Waste. At the present time, the primary sector waste flows in Cantabria are outstanding, since it is a region where the primary sector is one of the driving forces of the economy together with the tourism. The 86% of municipalities are classified as rural or semirural, and there, it is producing a large rural development from traditional craft production to intensive farms in which waste management is becoming a problem. In this work the methodology developed by European Environmental Agency has been used as a starting point in developing a set of Specific Indicators on the primary sector waste. Eleven indicators have been developed to evaluate the generation and management of forest, agricultural, livestock and food industry waste. These indicators allow not only monitoring the primary sector waste management, but also they highlight the precarious situation in relation to knowledge of actions undertaken in the sector in relation to their waste and with the information flows. Therefore, in this paper the analysis of difficulties for management the available information has been carried out

Propuesta de estrategias de gestión de residuos de construcción y demolición (RCDs) mediante el uso de herramientas de toma de decisiones

RESUMEN: Los Residuos de Construcción y Demolición (RCDs) se consideran prioritarios por la cantidad en la que se generan y su alto potencial de reciclaje. El objetivo principal de esta tesis es proponer y evaluar estrategias de gestión de RCDs mediante el uso de herramientas de toma de decisiones. Para ello se plantea: 1) estimar la generación y composición de RCDs mediante el análisis de los datos registrados en las plantas de tratamiento, ratios de generación de RCDs y desarrollo de escenarios de composición; 2) evaluar alternativas de gestión mediante Análisis Multicriterio; 3) evaluar la ubicación de las plantas de reciclaje de RCDs, mediante Sistemas de Información Geográfica, Análisis Multicriterio y Modelos de Optimización, y las contribuciones de cada herramienta; 4) evaluar el rendimiento de plantas de reciclaje de RCDs basándose en el análisis de flujo de materiales de las fracciones que componen la corriente de alimentación.ABSTRACT: Construction and Demolition Waste (C&DW) is considered as a priority waste stream for its recycling potential and the quantity in which is generated. The main objective of this thesis is the application of decision support tools to help decision making in all the stages of C&DW management. To do so, four stages are considered: 1) estimate C&DW generation and composition by waste facilities method, generation rate calculation and scenario development; 2) evaluate C&DW management alternatives by means of Multicriteria Analysis application; 3) evaluate the location of recycling facilities by means of Geographical Information System, Multicriteria Analysis and Optimization models application, and extract main contributions of each one; and 4) evaluate performance of recycling facilities taking into account key waste fractions and processes influencing it, using a mass balance approach