https://lutpub.lut.fi:443/handle/10024/158301 2026-05-13T19:25:29Z https://lutpub.lut.fi:443/handle/10024/167961 Medical waste management in Thailand and Vietnam Honkanen, Teija The purpose of this study is to provide information for feasibility assessment of medical waste incineration in South-East Asia. Countries selected for closer examination from the area are Thailand and Vietnam. The reason for selecting these countries is to limit the amount of needed research to a reasonable level. These countries have increasing population and present well the countries in this area. Thailand is classified as upper middle-income country whereas Vietnam is classified as lower middle-income country. There is also adequate amount of information available from these countries for the study. Information for the study has been collected from literature, by collecting information with questionnaire and from site visits. Questionnaire was formed based on decision making chain proposed by World Bank for assessment of waste incineration projects. Questionnaire was delivered for specialists in Thailand and Vietnam by using anonymous Webropol link. A part of answers was collected in Thai language and the Mahasarakham University helped in collecting these answers. Site visits were made to Mahasarakham area in Thailand and four facilities were visited there to study the current situation of medical waste handling in Thailand. Two of these facilities were hospitals and other two were clinics. It can clearly be seen that there is still some work to do in improving medical waste management both in Thailand and Vietnam. Medical waste management also needs some more resources in both countries. It can clearly be seen that the number of beds in hospitals is increasing strongly in near future, and this means that also amount of medical waste will increase. It is clearly visible that handling of medical waste has some alternatives, but they all require financing. Disinfection units are expensive so keeping up with the capacity to handle the medical waste requires some financing. Incinerator would be a feasible solution for handling the large amounts medical waste since existing incinerators are under dimensioned even for current needs not to mention the future needs. Building a local incinerator is seen as difficult task with all its requirements like modern flue gas cleaning and public acceptance. 2024-01-01T00:00:00Z https://lutpub.lut.fi:443/handle/10024/163487 Adsorption of phosphorous and arsenic oxyanions to metal hydroxide and oxide surfaces Martikainen, Mika This study focuses on two quite distinct elements, phosphorous and arsenic, and their removal from aqueous solutions by adsorption. On the surface, one could assume there is not much common with these two elements. Phosphorous is a vital macronutrient that forms the scaffolding of our DNA, cell membranes, and skeletons. Arsenic is toxic to us even at trace concentrations. Even though the biological and even the geochemical behaviour is different, the chemical behaviour of phosphorus and arsenic in aqueous systems is similar, and both elements form analogous species such as oxyanions like phosphate and arsenate. An additional similarity is their polluting effect on the environment. Both are dramatic pollutants; trace concentration of phosphorous causes paradoxically deterioration of water quality and aquatic life in rivers, lakes, and oceans through eutrophication while trace concentration of arsenic is directly toxic to most lifeforms. In addition to arsenic and phosphorous species, many other oxyanions like chromate, selenate, vanadate, and nitrate pose ever-increasing health and ecological problems. Understanding the behaviour of arsenate and phosphate oxyanions in aqueous solutions gives the background to address these oxyanions as well. The target of the work was to study real granular porous adsorbent materials, both commercial adsorbents and novel adsorbents, explicitly developed in this work. Granular adsorbents produced during this study were based on either solid industrial waste materials or solid precipitates made from virgin materials. All materials were produced on a semi-production scale, not in the laboratory, so any of the tested materials could be readily implemented in real water treatment applications. The main focus was on seven different iron-based adsorbents. Two of the iron-based materials (mixture of Goethite and Hydroniumjarosite) were explicitly produced for this thesis work in a semi-production scale process. For comparison, three gypsum-based, two Al2O3 -based and two TiO2 based adsorbents were also tested. Three of these comparison adsorbent materials were produced for this thesis work from industrial waste. The results show that novel Goethite-Hydroniumjarosite adsorbent granules have a high potential as adsorbents for phosphorous removal from waste waters. Also, the phosphate recovery process was developed for these adsorbent granules. It was shown that these adsorbents could be regenerated at least six times with alkali solution, and the adsorbed phosphorous can be recovered as calcium phosphate. It was also showed that the tested low-cost adsorbents produced by granulating industrial waste are highly efficient for phosphorous removal and due to low cost are an interesting alternative to commercial materials produced from virgin raw materials. Developed Goethite-Hydroniumjarosite adsorbents were tested intensively in arsenic remediation, and these materials showed high efficiency for arsenic removal. When tested according to NSF 53 standard, it was proven that these granular materials could remove As(V) below the drinking water limit of 10 µg As/L with a high capacity and productivity. It was also proven that these materials could remove both As(III) and As(V) species from drinking water. A statistical model for fixed-bed adsorption was developed for Goethite-Hydroniumjarosite granules. 2021-01-01T00:00:00Z https://lutpub.lut.fi:443/handle/10024/163033 Helium as a welding shielding gas : effects on CO₂ emissions by helium recovery and recycling system Korjala, Kalevi Helium as a welding shielding gas offers unique advantages for many applications. Helium provides positive effects to most of the shielding gas mixtures used with different materials and in a variety of welding processes. Helium is an inert gas which affords more heat input to the joint, thus increasing the welding efficiency. Mixed with argon, it increases welding speed and is advantageous in penetration of thick wall aluminum, copper, and titanium materials where it compensates the high heat conduction. Drawbacks of using helium are its availability, relatively high cost and the low density. Helium can be applied in shielding as a pure gas or as a component in the shielding gas mixtures. The objective of the thesis is to present a novel helium shielding gas recovery and recycling system devised for use in welding applications including its design and implementation. The novel system is designed by the author and it is unique in the welding shielding gas field. When using helium recovery and recycling, CO₂ emissions are reduced, and the climate change effects are decreased. The thesis is based on i) literature analysis and ii) developing and designing the novel recovery system which is new and unique. The literature review and analysis describe welding shielding gases and their properties. The section handling helium addresses the production methods and applications, general properties, and effects of helium as welding shielding gas to the productivity and welding economy. The practical experience of the author accumulated during an extensive over 30 years career in the gas production business and the literature review has laid a foundation for the innovation and design of a novel helium recovery system. The designed system allows the recovery of helium from the welding processes. This innovation can potentially offer significant cost savings for various applications, and improve the understanding of inert gases recovery, extraction, and reuse. This approach leads to more sustainable manufacturing practices, at the same time decreasing the negative environmental impact of the production process. The review of scientific publications on the shielding gas field demonstrates that the recovery and recycling system designed by the author is new and unique. It is new in the welding sector and the thesis has undisputed research and scientific novel value. 2021-01-01T00:00:00Z https://lutpub.lut.fi:443/handle/10024/155881 Aspects of factors affecting performance and emissions of small-scale bio heating boiler in a Northern European country Honkanen, Hannariina Emission production from small-scale bio heat production of less than 1 MW is poorly regulated in Finland. Wood is widely used for energy production in Finland, and the growing share of the demand for renewable energy production from total energy production pushes the use of biomasses further. One trend in energy production is the shift to smaller, more decentralized units that use local raw materials for energy. Heat entrepreneurship has been an increasing trend as a business and a way of offering renewable heating energy locally in different parts of Finland. This research reviewed the sustainability and efficiency, mainly from environmental but also from practical operations’ development perspective, of the use of bio heating boilers in northern climate conditions and according to local heat demand. The major task was to discuss fuel quality and the role of boiler operators in boiler efficiency and produced emissions, and to provide relevant information to the experts and operators. The research was carried out by studying both numerical data from laboratory tests for combustion of different quality fuels as well as qualitative data collected from experts operating with bio heating systems in the field. The information was gathered through literature search, interviews, and analyzing the data collected via previous questionnaires and combustion tests in Central Finland. The research reviewed the state of the steering mechanisms for the use of bio heating boilers, solid biofuels used in Finland, bio heating systems in use in the scope, applications and users of the boilers, and the state of environmental technology and emission control used in the systems. The data was analyzed from two sets of combustion tests conducted in the JAMK boiler testing laboratory for wood chips with different moisture levels in 2014 and 2017. The combustion tests were performed with a 500 kW bio heating boiler, which represents the average output boiler in use by heat entrepreneurs. The results consolidated the understanding of the correlation between the moisture content of the fuel and boiler efficiency, showing that dry fuel enables higher boiler efficiency than moist fuel. In addition, correlation between the carbon monoxide and particle emissions in flue gases were also confirmed. The combustion tests have a large number of variables, which makes the analyzing of the results quite challenging. The partial output-level tests showed the increasing need for boiler controls to balance the combustion process. In boiler controls, optimal combinations for the fuel feed, combustion air feed, and grate moves are the key issues for enhancing the boiler efficiency and to cut down on emissions. Rapid changes in terms of the heat demand of the boiler and changes in fuel quality bring about great challenges in terms of adjusting boiler settings. According to collected data, boiler users are interested in enhancing boiler efficiency and the maintenance of their equipment. However, a lack of awareness and technical expertise in proper boiler use exists, even with guidance manuals supplied from the manufacturers. Some equipment in use is old and is ill-equipped with modern and efficient technology. Tightening regulations will boost the implementation of flue gas purification technology in small-scale energy production. Automation technology provides opportunities for controls and monitoring of the state of the system. Maintenance and measurement services are utilized in a varied manner, but in some respects, an increased need for services in terms of guidance and adjustment can be predicted. 2018-01-01T00:00:00Z