In Canadian remote northern communities most electricity is generated by burning diesel fuel. However, because it is expensive to import fuel into remote communities the cost of electricity is very high. Waste management is also difficult in remote northern communities. The goal of this thesis was to investigate the co-gasification of refuse waste materials and biomass as a means of reducing solid waste volumes while also using locally available materials for power generation. As part of this research, thermo-gravimetric analysis (TGA) was investigated as a potential means of characterizing refuse derived fuels (RDF). Laboratory sample preparation of RDF for TGA had not been thoroughly considered. Laboratory sample preparation is important since RDF is very heterogeneous compared to other solid fuels and since TGA typically requires a very small sample size. A TGA method was applied to a variety of materials prepared from a commercially available RDF using a variety of procedures. The repeatability of the experimental results was related to the sample preparation methods. Cryogenic ball milling was found to be an appropriate means of preparing RDF samples for TGA. Applicability of the TGA method to the determination of the renewable content of RDF was considered. Air-blown auto-thermal gasification experiments using materials representative of waste and biomass were performed at 725°C, 800°C, and 875°C, using a 0.15 m internal diameter bubbling fluidized bed gasifier located at NRCan CametENERGY in Ottawa, Ontario. Commercially prepared RDF and PET scrap were used to represent waste materials. Commercially produced hardwood pellets were used to represent biomass. The co-gasification of hardwood pellets and commercially produced RDF indicated that each fuel make a contribution to the results which is proportional to its fraction in the feed mixture. Inclusion of the RDF in the fuel mixture led to bed agglomeration at the 875°C temperature condition. Higher temperatures were found to provide better conversion of the fuel to gas, and the limitation which inclusion of RDF places on the operating temperature of the gasifier negatively affects conversion of biomass. Results obtained with RDF suggested that utilization of mixed waste for a thermal conversion process located in a Canadian remote northern community is probably not a viable option. It was then decided to target plastic waste in particular. Plastic could be source-separated, collected, and gasified alongside biomass. Polyethylene terephthalate (PET), which is often used for food and beverage containers, was chosen to represent plastic. Initially, attempts were made to co-gasify mixtures of PET pellets and hardwood pellets. These attempts failed due to the formation of coke above the bed. To alleviate these problems hardwood-PET composite pellets were manufactured and these were gasified at 725°C, 800°C, and 875°C. Inclusion of PET in the pellets dramatically increased the amount of tar produced during gasification.

This work focuses on effective utilization of municipal solid waste in heat and power systems. The effectivity in this work is evaluated from an economic as well as an environmental viewpoint. In the introductory part a review of legislation and state-of-the art in the fields of energetics and waste management of European Union is presented. Next an optimization tool NERUDA, created on the author’s workplace, is introduced. NERUDA consists of basic modules on which creation has the author been participating. The thesis is divided into two main parts that describe two NERUDA’s modules. First deals with a techno-economic model of waste-to-energy plants and is called Flexi model. The main output is a dependency of gate fee on capacity. Second part is devoted to the implementation of new module into the NERUDA system. This module is an environmental criterion for evaluation of the effectivity of waste utilization in the waste management and energetics.

The existing methods of sewage sludge and non-recyclable plastic waste management turn out to be unsatisfactory in long terms. Landfilling of the high-calorific-value wastes will be lim-ited in near future and the potential soil contamination by some of the sewage sludge contents led to several legislation changes in the field of using the sewage slugde in agriculture. The presented thesis aims to find an integrated solution for sewage sludge and plastic waste with a focus on the possibility of phosphorus recovery from the resulting ash. Based on the study of the available separate solutions and relevant legislative regulations, three variants of possible integration were proposed. Subsequently, the basic energy and material balance of these vari-ants were performed using W2E software.

The goal of this work is compilation of computational model of thermal stage and heat recovery block of modern unit for thermal processing of municipal solid waste. The model is based on mass and enthalpy balances and it makes possible to estimate the value of energy transferred to water in secondary combustion chamber, outside the heat recovery blok. The model is verified by implementation of real operational data of an up-to-date unit with annual capacity of 100 kt for thermal processing of municipal solid waste and then it is used for analysis of changing input parameters, i. e. change in lower heating value of incinerated waste.

This thesis deals with analysis of operation data for purposes of optimization. The thesis is divided into four chapters. First chapter focuses on present and future development in waste management legislation. It mainly deals with prevention, recycling and disposal of waste. Second chapter more closely describes waste-to-energy process. This chapter also describes the technology of municipal waste incinerator in Liberec, Termizo, a.s. Third chapter starts with description of tools used in design of the models based on operation data. Then the models for individual technological nodes are described. The last part is focused on building a complex model of Termizo using previous results.

This thesis deals with the evaluation of the strategic investment in the waste-to-energy plant development. The central supply of heat and the incineration plant connection can be provided for example by the distribution network. The objective is to find financially feasible solution regarding uncertain development of waste management and energy market. A heat supplies to district heating network significantly influences the strategic decision. A two-stage stochastic programming based on the scenarios and the GAMS software were applied to solve this task. The main contribution of this thesis is decision on crucial parameters of the waste-to-energy plant.

PhD thesis deals with the application of the simulation and optimization methods in the waste-to-energy field. An introduction describes the current state of the waste management in the EU with the focus on the Czech Republic. In the following chapter the evaluation criteria for investment intentions and the basic principles of stochastic programming are discussed. The core of the work lays in the mathematical models for the planning and operation of the process plants as well as in the mathematical models for the waste collection. The transportation problem involves all considered technological elements and therefore it is possible to simulate the waste streams between the producers and processors. This approach is demonstrated with five case studies. In the first three studies the calculations for the potential investor are presented. The main outcome of these case studies is the determination of the level of attractiveness of investment and the identification the greatest risks. Another case study is devoted to an analysis with the focus on perspective of government policies and in the last case study the issue of the waste management is analyzed in detail from the perspective of the waste producers. Developed computational tools are flexible and can be further developed and adapted based on the objectives of the specific tasks.

This thesis is devoted to the construction of new waste-to-energy plants in a territory where is already another fossil-fuel power station in operation. The aim is to create a mathematical model and prove that those two devices are able to cooperate effectively using same technology. Exactly assembled model under real operating have characteristics of a mixed integer nonlinear programming. The optimization software GAMS is used for its calculation. The complexity of the model, however, is at a level that solutions in bad initial conditions ends in local optima, or not found at all. This thesis is devoted to the elimination of non-linearity using binary variables and heuristic so the task was solved with acceptable time limits to guarantee an optimal solution.

PhD thesis deals with the application of simulation, forecasting and optimization methods in the waste management. An introduction describes current state and outlook in the waste management in the Czech Republic. The following chapter analyzes the available data base in the field of the waste management in the Czech Republic, focusing on the specifics and problems such as variable availability of spatially and hierarchically structured, heterogeneous input data. The core work is the computational tool named Justine, which represents the balance system, ensuring consistency of values for the standalone and aggregated data, in terms of their composition and distribution in intended area and time. Development of the tool was motivated by the need to predict the production and composition of various types of waste. The application of the concept is shown in three case studies, focusing on the prognosis of hazardous waste, the forecast of production and composition of municipal solid waste and components of separated waste collection, and estimation of the waste with waste-to-energy potential, all in the Czech Republic. The outputs of the tool represent valuable inputs for the related optimization supply chain models, which are used e.g. for the design of new waste-to-energy facilities.

The EU has embarked on a resource efficiency trajectory in order to solve resource scarcity and general sustainability issues. The conversion of food waste into fuel is considered resource efficient as it makes use of resources that would otherwise be discarded. On the other hand, the food sector affects the environment substantially as it is inherently resource intensive and excessive. The purpose of the study was to assess how resource efficient the food waste substrate (feedstock for energy production) is from a life-cycle perspective. The study also aimed to determine if associated Swedish incentives and current market signals promote resource efficiency in Sweden. The food waste substrate has a complex life-cycle and current analyses neglect crucial life-cycle impacts. This makes resource efficiency difficult to determine in absolute terms. The first resource efficiency principle, that promotes the use of fewer inputs, becomes questionable as the food waste substrate has twice as many input stages in comparison to the food crop substrate. The second principle, stating that the food waste substrate should contribute to a low-carbon economy, also falls short due to a calculation method that neglects crucial emission stages. Due to the absent life-cycle perspective, crucial environmental impacts associated with food production are neglected. This affects the achievement of the Swedish Generation Goal and environmental quality objectives. The study concludes that the food waste substrate should undergo a thorough life-cycle analysis. Furthermore, it should be compared to other biofuel options in order to determine degree of resource efficiency. Only then can an appropriate set of EU and national policy measures be instated to safeguard scarce resources and promote a sustainable agriculture and energy sector.