Browsing by Author "Swiss Federal Institute of Aquatic Science and Technology"

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    Analysis of time-dependent mercury flows through the use of thermometers and sphygmomanometers in Thailand
    (2017-05-01) Manaporn Wongsoonthornchai; Ruth Scheidegger; Suphaphat Kwonpongsagoon; Hans Peter Bader; Mahidol University; Center of Excellence on Environmental Health and Toxicology (EHT); Swiss Federal Institute of Aquatic Science and Technology
    © Int. J. of GEOMATE. Thermometers and sphygmomanometers pose a potentially large source of mercury emissions to the environment due to their high elemental mercury content. Many countries, e.g. most European countries, US have banned their uses already and many more strictly limited their use. However, in Thailand these mercury-based devices are still used, accumulating large stocks in the use phase as well as in landfills. To understand the development of mercury stocks and flows from thermometers and sphygmomanometers, a time-dependent mathematical material flow model is used in this study. The flows of mercury through these two products were calculated based on data between the years of 1962 and 2013. The simulation showed that the stock of mercury in thermometers is about 20 times smaller than the stock in sphygmomanometers. However the sum of waste flows and emissions to air and water from thermometers is 3 times larger than from sphygmomanometers. The reason is the lifetime of thermometers which is about 70 times shorter than the lifetime of sphygmomanometers. The calculated emission to air from mercury thermometers in hospitals can explain the higher mercury level measured in urine of health care staff. In order to reduce the mercury flows to the environment mercury thermometers should be replaced by alternative products as soon as possible.
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    Emergy distribution in oxidation pond and constructed wetland treating a domestic wastewater
    (2011-07-01) Thaneeya Perbangkhem; Doulaye Kone; Chongchin Polprasert; Suranaree University of Technology; Swiss Federal Institute of Aquatic Science and Technology; Mahidol University
    Two identical pilot-scale reactors - one as an oxidation pond (OP) and the other as a freewater- surface-flow constructed wetland (CW) planted with Cyperus papyrus - were fed with a lowstrength domestic wastewater at the organic loading rate of 16 kg BOD/ha-d. The purpose of this study was to investigate how the solar energy dissipated into the biomass productivities during the wastewater treatment course, using emergy analysis. In the experiments, both treatment systems were operated with daily draw-and-fill mode for two months. After that, the biomass productivities were measured from the weight increases and effluent samplings were performed to bring about laboratory analysis of water-quality parameters. Based on the emergy analyses, the CW unit was found to use lower emergy for pollutant removal, corresponding to the lesser ecological waste removal potential (EWRP) than that of OP unit. As the algal cells were dominant in the OP, they contributed to 80 percent of the total emergy input, resulting in a highly turbid effluent. The emergy transfer was found to be most effective in the CW unit with the efficiencies of 6 and 67 percent for plant and fish productions, respectively. Thus, the comparative emergy assessment performed in this study indicated a higher potential of CW over OP to be used for, not only pollution control, but also biomass productions of fish and wetland plant for further human's utilization.
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    Integrating Spatial Land Use Analysis and Mathematical Material Flow Analysis for Nutrient Management: A Case Study of the Bang Pakong River Basin in Thailand
    (2015-05-01) Wallapa Kupkanchanakul; Suphaphat Kwonpongsagoon; Hans Peter Bader; Ruth Scheidegger; Mahidol University; Thailand Ministry of Education; Swiss Federal Institute of Aquatic Science and Technology
    © 2015, Springer Science+Business Media New York. Rivers in developing and emerging countries often lack good water quality. Tools to assess the water quality in rivers, including identification of possible sources of pollution, are therefore of increasing importance. The aim of this study is to apply mathematical material flow and spatial land use analyses to identify and geographically locate the main nitrogen and phosphorus sources and processes in Bang Pakong Basin (BPB). Potential measures to mitigate the nitrogen and phosphorus loads to the water system can then be efficiently evaluated. The combination of these two methods reveals the overall nutrient load as well as local “hot spots.” This allows possible mitigation measures to be discussed with regard to their spatial location. This approach goes beyond previous work in which mathematical material flow analysis was shown to be a useful tool to investigate sources of nutrients regardless of their location. The results show that the main sources contributing nutrients to waterways are aquaculture, such as shrimp, tilapia, catfish, and sea bass farming, as well as rice paddies along the main river. Additional sources contributing nutrients to this basin are field crops, livestock, aquaculture, households, and industry. High levels of nutrient inflows come from feeds and fertilizers through aquaculture and rice cultivation. The excess nutrients run into the waterways by direct discharge from aquaculture and runoff processes from rice paddies. Scenario analysis shows that management practices for aquaculture, rice, pig, and poultry farming are key drivers for reducing nutrients in the BPB.
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    Modeling Mercury Flows in Thailand on the Basis of Mathematical Material Flow Analysis
    (2016-01-01) Manaporn Wongsoonthornchai; Suphaphat Kwonpongsagoon; Ruth Scheidegger; Mahidol University; Center of Excellence on Environmental Health and Toxicology; Swiss Federal Institute of Aquatic Science and Technology
    © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Mercury pollution is a global problem, because it can be transported across borders and released from both natural and anthropogenic sources. In this paper, we studied the mercury flows in Thailand originating from anthropogenic sources (from intentional and unintentional use) in 2010, giving for the first time a comprehensive overview over mercury stock and flows including emissions in Thailand. Mathematical material flow analysis was applied to calculate the stock of mercury and its flows in the country. All available data from various sources such as statistical data, literature, surveys, and interviews with experts were used. The results showed that total mercury emissions were about 57 000kg/year, 61% of them to land, 35% to air, and 4% to water. The largest mercury input comes as impurities in imported zinc, followed by domestically mined gold ores in which mercury is also an impurity. The largest stock of mercury is found in dental amalgam, followed by air conditioners and sphygmomanometers. The scenarios developed here were designed to reduce mercury emissions. Unintentional use alone can reduce total mercury emissions by about 33%, while around 5% of the potential reduction comes from intentional use. Changes in combined unintentional and intentional use can lead to the highest potential reduction.
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    Modelling cadmium flows in Australia on the basis of a substance flow analysis
    (2007-11-01) Suphaphat Kwonpongsagoon; Hans Peter Bader; Ruth Scheidegger; University of New South Wales (UNSW) Australia; Swiss Federal Institute of Aquatic Science and Technology; Mahidol University
    This paper, which is an extension of the Suphaphat Kwonpongsagoon's PhD thesis (2006), investigates a stationary model designed to evaluate substance flows for a case study of cadmium (Cd) in Australia. It covers the mining industry, the production and use of goods for agriculture, construction and households as well as the environmental sectors of agriculture, surface water and landfills. The model is calibrated with Cd flow data obtained in a previous study. The results of the calibrated model are consistent with those of other studies from other countries. Possible measures and options to reduce the Cd flows to various environmental sectors are discussed by applying sensitivity analysis and parameter variations to the calibrated model. As "agriculture" was used to illustrate one of the most important processes discussed in this paper, the results show that the most effective measures are the reduction of the Cd content in fertilizers and of atmospheric Cd deposition. It is concluded that a mathematical model is very useful for understanding a system that is crucial for environmental management. © 2007 Springer-Verlag.