George Perkoulidis

A multi-criteria ranking of different technologies for the anaerobic digestion for energy recovery of the organic fraction of municipal solid wastes

This paper describes a conceptual framework and methodological tool developed for the evaluation of different anaerobic digestion technologies suitable for treating the organic fraction of municipal solid waste, by introducing the multi-criteria decision support method Electre III and demonstrating its related applicability via a test application. Several anaerobic digestion technologies have been proposed over the last years; when compared to biogas recovery from landfills, their advantage is the stability in biogas production and the stabilization of waste prior to final disposal. Anaerobic digestion technologies also show great adaptability to a broad spectrum of different input material beside the organic fraction of municipal solid waste (e.g. agricultural and animal wastes, sewage sludge) and can also be used in remote and isolated communities, either stand-alone or in conjunction to other renewable energy sources. Main driver for this work was the preliminary screening of such methods for potential application in Hellenic islands in the municipal solid waste management sector. Anaerobic digestion technologies follow different approaches to the anaerobic digestion process and also can include production of compost. In the presented multi-criteria analysis exercise, Electre III is implemented for comparing and ranking 5 selected alternative anaerobic digestion technologies. The results of a performed sensitivity analysis are then discussed. In conclusion, the performed multi-criteria approach was found to be a practical and feasible method for the integrated assessment and ranking of anaerobic digestion technologies by also considering different viewpoints and other uncertainties of the decision-making process.

A multicriteria facility location model for municipal solid waste management in North Greece

Abstract Up to 2002, Hellenic Solid Waste Management (SWM) policy specified that each of the country’s 54 prefectural governments plan its own SWM system. After 2002, this authority was shifted to the country’s 13 regions entirely. In this paper, we compare and contrast regional and prefectural SWM planning in Central Macedonia. To design the prefectural plan, we assume that each prefecture must be self-sufficient, and we locate waste facilities in each prefecture. In contrast, in the regional plan, we assume cooperation between prefectures and locate waste facilities to serve the entire region. We present a new multicriteria mixed-integer linear programming model to solve the location–allocation problem for municipal SWM at the regional level. We apply the lexicographic minimax approach to obtain a “fair” nondominated solution, a solution with all normalized objectives as equal to one another as possible. A solution to the model consists of locations and technologies for transfer stations, material recovery facilities, incinerators and sanitary landfills, as well as the waste flow between these locations.

The use of multi-criteria decision analysis to tackle waste management problems: a literature review.

Problems in waste management have become more and more complex during recent decades. The increasing volumes of waste produced and social environmental consciousness present prominent drivers for environmental managers towards the achievement of a sustainable waste management scheme. However, in practice, there are many factors and influences – often mutually conflicting – criteria for finding solutions in real-life applications. This paper presents a review of the literature on multi-criteria decision aiding in waste management problems for all reported waste streams. Despite limitations, which are clearly stated, most of the work published in this field is reviewed. The present review aims to provide environmental managers and decision-makers with a thorough list of practical applications of the multi-criteria decision analysis techniques that are used to solve real-life waste management problems, as well as the criteria that are mostly employed in such applications according to the nature of the problem under study. Moreover, the paper explores the advantages and disadvantages of using multi-criteria decision analysis techniques in waste management problems in comparison to other available alternatives.

A multi-criteria assessment of scenarios on thermal processing of infectious hospital wastes: A case study for Central Macedonia

In Greece more than 14,000 tonnes of infectious hospital waste are produced yearly; a significant part of it is still mismanaged. Only one off-site licensed incineration facility for hospital wastes is in operation, with the remaining of the market covered by various hydroclave and autoclave units, whereas numerous problems are still generally encountered regarding waste segregation, collection, transportation and management, as well as often excessive entailed costs. Everyday practices still include dumping the majority of solid hospital waste into household disposal sites and landfills after sterilization, still largely without any preceding recycling and separation steps. Discussed in the present paper are the implemented and future treatment practices of infectious hospital wastes in Central Macedonia; produced quantities are reviewed, actual treatment costs are addressed critically, whereas the overall situation in Greece is discussed. Moreover, thermal treatment processes that could be applied for the treatment of infectious hospital wastes in the region are assessed via the multi-criteria decision method Analytic Hierarchy Process. Furthermore, a sensitivity analysis was performed and the analysis demonstrated that a centralized autoclave or hydroclave plant near Thessaloniki is the best performing option, depending however on the selection and weighing of criteria of the multi-criteria process. Moreover the study found that a common treatment option for the treatment of all infectious hospital wastes produced in the Region of Central Macedonia, could offer cost and environmental benefits. In general the multi-criteria decision method, as well as the conclusions and remarks of this study can be used as a basis for future planning and anticipation of the needs for investments in the area of medical waste management.

Integrated assessment of a new Waste-to-Energy facility in Central Greece in the context of regional perspectives

The main aim of this study is the integrated assessment of a proposed Waste-to-Energy facility that could contribute in the Municipal Solid Waste Management system of the Region of Central Greece. In the context of this paper alternative transfer schemes for supplying the candidate facility were assessed considering local conditions and economical criteria. A mixed-integer linear programming model was applied for the determination of optimum locations of Transfer Stations for an efficient supplying chain between the waste producers and the Waste-to-Energy facility. Moreover different Regional Waste Management Scenarios were assessed against multiple criteria, via the Multi Criteria Decision Making method ELECTRE III. The chosen criteria were total cost, Biodegradable Municipal Waste diversion from landfill, energy recovery and Greenhouse Gas emissions and the analysis demonstrated that a Waste Management Scenario based on a Waste-to-Energy plant with an adjacent landfill for disposal of the residues would be the best performing option for the Region, depending however on the priorities of the decision makers. In addition the study demonstrated that efficient planning is necessary and the case of three sanitary landfills operating in parallel with the WtE plant in the study area should be avoided. Moreover alternative cases of energy recovery of the candidate Waste-to-Energy facility were evaluated against the requirements of the new European Commission Directive on waste in order for the facility to be recognized as recovery operation. The latter issue is of high significance and the decision makers in European Union countries should take it into account from now on, in order to plan and implement facilities that recover energy efficiently. Finally a sensitivity check was performed in order to evaluate the effects of increased recycling rate, on the calorific value of treated Municipal Solid Waste and the gate fee of the candidate plant and found that increased recycling efforts would not diminish the potential for incineration with energy recovery from waste and neither would have adverse impacts on the gate fee of the Waste-to-Energy plant. In general, the study highlighted the need for efficient planning in solid waste management, by taking into account multiple criteria and parameters and utilizing relevant tools and methodologies into this context.

Modelling of a downdraft gasifier fed by agricultural residues.

A non-stoichiometric model for a downdraft gasifier was developed in order to simulate the overall gasification process. Mass and energy balances of the gasifier were calculated and the composition of produced syngas was predicted. The capacity of the modeled gasifier was assumed to be 0.5 MW, with an Equivalence Ratio (EQ) of 0.45. The model incorporates the chemical reactions and species involved, while it starts by selecting all species containing C, H, and O, or any other dominant elements. Olive wood, miscanthus and cardoon were tested in the formulated model for a temperature range of 800-1200°C, in order to examine the syngas composition and the moisture impact on the supplied fuel. Model results were then used in order to design an olive wood gasification reactor.

Characteristics of wastes from electric and electronic equipment in Greece: results of a field survey:

The lifespan of electric and electronic equipment is becoming shorter and the amount of related waste is increasing. This study aimed to contribute to the knowledge about qualitative and quantitative characteristics of such wastes in Greece. Specifically, results are presented from a field survey, which took place in the city of Thessaloniki, Greece, during the year 2002. The survey was conducted with suitable questionnaires in department stores and in households of various municipalities. Household appliances were grouped as follows: (A) large (refrigerator, freezer, washing machine, clothes dryer, electric cooker, microwave oven, electric heater), (B) small (vacuum cleaner, electric iron, hair dryer), (C) information technology and telecommunication equipment(PC, laptop, printer, phone) and (D) consumer equipment(radio, TV, video, DVD, console). The analysis indicated that the lifespan of all new goods is gradually reducing (apart from refrigerators, for which the lifespan was surprisingly found to be increasing) and provided linearized functions for predicting the lifespan, according to the year of manufacture, for certain large appliances.

Open dumps in the Hellenic prefecture of Laconia: statistical analysis of characteristics and restoration prioritization on the basis of a field survey

This study presents an assessment of the current status of open dumps in Laconia prefecture of Peloponnese in southern Greece, where all open dumps are targeted for closure by 2008. An extensive field survey was conducted in 2005 to register existing sites in the prefecture. The data collected included the site area and age, waste depth, type of disposed waste, distance from nearest populated area, local geographical features and observed practices of open burning and soil coverage. On the basis of the collected data, a GIS database was developed, and the above parameters were statistically analysed. Subsequently, a decision tool for the restoration of open dumps was implemented, which led to the prioritization of site restorations and specific decisions about appropriate restoration steps for each site. The sites requiring restoration were then further classified using Principal Component Analysis, in order to categorize them into groups suitable for similar restoration work, thus facilitating fund allocation and subsequent restoration project management.

Multi-objective ranking of pareto-optimal scenarios for regional solid waste management in Central Greece

This paper presents a modeling approach and an application of the problem of locating facilities and allocating quantities of municipal wastes at regional level. A model-generating framework that was developed and customized for this purpose is used. It includes 0–1 optimization models and multiple-criteria analysis. The application area is the region of Sterea Ellada in central Greece. Necessary data was collected by field surveys and questionnaires. The proposed integrated best alternative scenarios, which were finally ranked by the Electre III multiple-criteria method, were determined after a single-criterion optimization to environmental (greenhouse effect, final disposal to landfill), financial (total cost of the system) and technological (facilities’ typologies) criteria.ΠερίληΨηΣτην εργασία αυτή αντ ιμετωπίζεται τΕ πρόβ λημα της χωρΕθέτησης εγκαταστάσεων και τη ς κατανΕμής απΕρριμμ άτΕΕν σε περιφερειακ ό επίπεδΕ, μέσω της παρ Ευσίασης σχετικΕύ μΕ ντελΕυ και μελέτης πε ρίπτωσης. Για τΕν σκΕπ ό αυτό χρησιμΕπΕιείτ αι ένα πλαίσιΕ παραγω γής μΕντέλων πΕυ αναπτύχ θηκε ειδικά για αυτόν τΕν σκΕπό. Περιλαμβάν ει δικτυακό μΕντέλΕ βελτιστΕπΕί ησης ακεραίΕυ πρΕγρα μματισμΕύ και πΕλυκρ ιτηριακή ανάλυση. Ως π εριΕχή εφαρμΕγής χρη σιμΕπΕιήθηκε η Περιφ έρεια Στερεάς Ελλάδα ς, όπΕυ η απαραίτητη πληρΕφΕρία συλλέχθη κε με έρευνα πεδίΕυ κα ι ερωτηματΕλόγια. Τα π ρΕτεινόμενα βέλτιστα ΕλΕκληρίΕμ ένα διαχειριστικά σε νάρια, τα ΕπΕία τελικά ιεραρχήθηκαν με την π Ελυκριτηριακή μέθΕδ Ε Electre III, πρΕέκυΨαν κατόπι ν μΕνΕκριτηριακής βε λτιστΕπΕίησης τΕυ δικτυακΕύ μΕντέλ Ευ ως πρΕς 5 κριτήρια, δ ηλ. τΕυ φαινΕμένΕυ θερ μΕκηπίΕυ, της τελικά δ ιατιθέμενης πΕσότητ ας, τΕυ ΕλικΕύ κόστΕυς τΕυ συστήματΕς της αν ακτΕύμενης πΕσότητα ς υλικίόν πρΕς ανακύκ λΕιση και της ανακτΕύ μενης ενέργειας. Λέξεις-κλειδιά: ΜΕνάδ ες διαχείρισης απΕρρ ιμμάτων, ΠΕλυκριτηρι ,ακή ανάλυση, Μελέτη περίπτωσης.