This work aimed to investigate the groundwater situation in and around Mina din Chisinau, an underground limestone mine in Chisinau, Moldova, in order to contribute to a sustainable solution to its flooding problem. Work on-site was done including visits inside the mine, to points of hydrogeological relevance to the mine, well inventories/search, and an attempt at an infiltration test. An on-site literature study was done using printed materials as well. Water quality in the mine and locally was examined. A GIS interpolation of groundwater levels was done and groundwater flow was visualized. Groundwater flow locally is thought to be in the west-southwest direction. Water quality is good but high in minerals, making it suitable for blending with surface water. A proposed project to pump groundwater from outside the mine to the municipal drinking water system seems to be a suitable solution, however groundwater modelling, ideally based on pumping tests, should be done to inform the system dimensions and design. / Detta arbete syftade till att undersöka grundvattensituationen i och runt Mina din Chisinau, en underjordisk kalkstensgruva i Chisinau, Moldavien, för att bidra till en hållbar lösning på dess översvämningsproblem. Arbetet på plats utfördes inklusive besök i gruvan, till punkter av hydrogeologisk relevans för gruvan, brunnsinventeringar och ett försök till ett infiltrationstest. En litteraturstudie på plats gjordes också med tryckt material. Vattenkvaliteten i gruvan och lokalt undersöktes med hjälp av befintligt resultat. En GIS-interpolering av grundvattennivån gjordes och grundvattenflödet visualiserades. Grundvattenflöde tros vara lokalt i väst-sydvästlig riktning. Vattenkvaliteten är god men mineralrik, vilket gör den lämplig för blandning med ytvatten hos vattenverket. Ett föreslaget projekt för att pumpa grundvatten från utanför gruvan till det kommunala dricksvattensystemet verkar vara en lämplig lösning, men grundvattenmodellering, helst baserat på pumptester, bör göras för att informera systemets dimensioner och design.

More and more people live in cities, cities that both present opportunities, in terms of potential sustainable growth and challenges, for example regarding insufficient infrastructure and waste management. There are several examples on initiatives to make cities reach their sustainability potential; one is to turn municipal organic waste, MOW, and sewage sludge into biogas and use it to produce electricity and/or heat or to upgrade it to biomethane and use it as a fuel in for example public transport or feed it to a gas grid. This study has focused on the potential and feasibility of producing and using biogas/biomethane as well as the remains from the production process, called digestate, in Chisinau, the capital of Moldova. For the most feasible options an indication of the environmental improvement and economic performance was also estimated. The study included biogas produced from municipal organic waste, sewage sludge and methane collected at landfills. For the areas of use, electricity or heat produced from biogas was included as well as using biomethane in public transport or feeding it to the gas grid and to use the digestate as biofertilizer. Since multiple factors needs to be considered in order to adequately assess the potential and feasibility a multi-criteria approach was used for developing a framework based on an early assessment tool for biomethane solutions in the urban context. In summary it is indicated that there are good conditions for biogas production in Chisinau with biogas production from sewage sludge being included in the ongoing rehabilitation of the largest wastewater facility and methane collection from the largest landfill historically being part of the operations and planned (although not confirmed) to soon be part of these again. However, the largest potential is for municipal organic waste where the main impediments relates to financial issues and to some extent legislation that indirectly favour short term landfilling. When investigating the possible use of the digestate as biofertilizer the outlooks are considerably less promising than for the supply side. Despite the fact that the law explicitly allows the use of digestate (both from MOW and sewage sludge) the lack of knowledge within the farmer community result in a low or non-existent customer demand. Regarding the possible use of biogas/biomethane it was concluded that electricity production is the most feasible option and heat generation placing as the second most feasible. Feeding the gas to the grid appears more difficult and the least likely option is for the biogas to be used within public transport. Overall it is in general technically possible to use the gas in terms of infrastructure and there is some demand, especially for electricity and heat. The biggest inhibitory factors are rather institutional since biogas in general is overlooked or not prioritized in the strategies leading to a shortcoming in economical instruments or funds and to some extent in the legislation. This thesis is complemented by an executive summary with the same name, both in English and translated to Romanian.

Possibilities for energy recovery from sludge at Chişinȃu wastewater treatment plant have been investigated and evaluated. One way of recovering energy from sludge is to produce biogas through anaerobic digestion. Which method of biogas usage that is to prefer in Chişinȃu has been evaluated from a cost-efficiency point of view. There is a possibility that a new waste incineration plant will be built next to the wastewater treatment plant, and therefore solutions that benefit from a co-operation have been discussed. The results show that biogas production would be suitable and profitable in a long time perspective if the gas is used for combined heat and power production. Though, the rather high, economical interest rates in Moldova are an obstacle for profitability.

<p>Possibilities for energy recovery from sludge at Chişinȃu wastewater treatment plant have been investigated and evaluated. One way of recovering energy from sludge is to produce biogas through anaerobic digestion. Which method of biogas usage that is to prefer in Chişinȃu has been evaluated from a cost-efficiency point of view. There is a possibility that a new waste incineration plant will be built next to the wastewater treatment plant, and therefore solutions that benefit from a co-operation have been discussed. The results show that biogas production would be suitable and profitable in a long time perspective if the gas is used for combined heat and power production. Though, the rather high, economical interest rates in Moldova are an obstacle for profitability.</p>

The thesis outlined in this report has been done as a sub-project in cooperation between the municipalities Borlänge in Sweden and Chisinau in Moldova. The project aimed to explore the region's economic and environmental opportunities for waste incineration with energy recovery, also known as Waste to Energy. At present, the solution to the waste situation is unmonitored landfills with smaller sorting operations. Environmentally, this is a poor solution and although there are plans for change, no specific strategy has been presented. Another important issue is Moldova's dependence on foreign produced energy. The country's energy system is dependent on imported natural gas, and only a small part of the country's electrical energy is produced domestically. What makes the waste to energy so interesting for this region is that it contributes to an improvement in both of these issues by using the waste as fuel to reduce energy dependency. The study has been done without specific waste composition data for the Chisinau region. With this in mind a dynamic model in several steps has been made, designed to obtain new results depending on what waste composition is specified. The results of this study show that implementation of a waste incineration plant in the Chisinau energy system is economically and environmentally feasible, given the current conditions. The proposed plant is designed to annually handle 400,000 tonnes of waste, and would with the assumed waste composition deliver 560 GWh of district heat and 260 GWh of electric energy. This production provides an annual profit of 31.6 M €, which gives a positive net present value after the project amortization. Compared with the city's current solution with landfills and gas turbines, the project also provides a significant environmental improvement. During the plant's design lifetime, greenhouse gas emissions are 53.9%, and only 6.8% with the assumption that only a portion of the carbon content of the waste is of fossil origin.