AHW25-01

Room:101B

Time:May 27 14:15-14:35

Occurrence of health-related water microorganisms in groundwater of the Kathmandu
Valley, Nepal
HARAMOTO, Eiji1∗
1University of Yamanashi

Waterborne diseases are one of the most serious public health concerns in the Kathmandu Valley, Nepal; however, the occurrence of waterborne pathogens (viruses, protozoa, and pathogenic bacteria) as well as their indicator microorganisms in aquatic
environments of the valley has not yet fully understood.
Through the Global COE program entitled ’Evolution of Research and Education on Integrated River Basin Management in
Asian Region’ and the Science and Technology Research Partnership for Sustainable Development (SATREPS) program entitled ’Hydro-microbiological Approach for Water Security in Kathmandu Valley, Nepal’, we have been trying to determine theoccurrence of health-related water microorganisms in water samples of the Kathmandu Valley. Examples of our findings are as
follows: (1) Levels of contamination of health-related water microorganisms in groundwater are quite different depending ontypes of wells; (2) Groundwater is contaminated with animal feces as well as human feces; (3) Waterborne pathogens are frequently detected even in Escherichia coli - and/or total coliform-negative samples, indicating that they are unsuitable indicatorsof pathogen contamination of groundwater.
Some of the results obtained to date in the projects will be presented.
Keywords: Health-related water microorganism, Microbial water quality indicator, Microbial source tracking

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AHW25-02

Room:101B

Time:May 27 14:35-14:50

Ammonium sources of groundwater in Kathmandu Valley, Nepal
NAKAMURA, Takashi1∗ ; NISHIDA, Kei1 ; YAMAMOTO, Yuki2 ; HIRAGA, Kodai2 ; KHANAL, Anoj3 ;SHRESTHA, Suresh das3 ; KAZAMA, Futaba11ICRE, University of Yamanashi, 2 faculty of eng., University of Yamanashi, 3 CDG, Tribhuvan University

Groundwater quality is a critical problem in the Kathmandu Valley, Nepal. The population of the city increased by 6 times in
the last six decades and more than half of water demand depends on groundwater source. Microbial and nitrogen contamination
causes loss of water resources, nevertheless, understanding of nitrogen source and dynamics in groundwater system still remains
insufficient in the central area of the valley. Objective of this study is to identify source of ammonium contamination on shallow
and deep groundwater.
Groundwater samples were collected from 34 shallow wells and 5 deep tube wells in September 2014. Ammonium ion weredetected from 12 shallow wells and 2 deep wells. Those ammonium concentrations ranged from 1.3 to 103 ppm. Nitrogenisotope values in ammonium ranged from -0.3 to 9.3 permill; this wide range of the nitrogen isotope values suggested possibilityof ammonium contamination from natural and anthropogenic sources.
Acknowledgement
This study are supported by the Science and Technology Research Partnership for Sustainable Development Program (SATREPS,Project Manager: Prof. Narendra Man Shakya and Prof. Futaba Kazama) of Japan Cooperation Agency (JICA)/Japan Scienceand Technology Agency (JST).

Keywords: Kathmandu, Urban, Groundwater, Nitrogen isotope in ammonium, Nitrogen and oxygen isotope in nitrate

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AHW25-03

Room:101B

Time:May 27 14:50-15:05

Effects of reduced leakage from the water main on the spring at Otomeyama Park inShinjuku ward
TAKANO, Yuki1∗ ; YOSHIMURA, Kei2 ; MURAKAMI, Michio3 ; UEMURA, Takeshi41Dept. of Earth and Planetary Phys., Univ. Tokyo, 2 Atmosphere and Ocean Research Institute, Univ. Tokyo, 3 IIS, Univ. Tokyo(Present address: School of Medicine, Fukushima Med. Univ.), 4 Kaijo Junior and Senior High School
Decreacing of spring discharge in Tokyo is a problem since it leads to lost of the place for relaxation and refreshment forthe citizens. To date, it has considered that increasing of impervious land cover followed by rain infiltration blocking results indecline of spring discharge. Although declining in a spring discharge in Tokyo was reported by several investigations, the causesof the declining was not quantitatively discussed based on the water budget. In order to estimate the causes, we observed springdischarge at Otomeyama Park in Shinjuku ward for 5-years (2009-2013) and evaluate water budget of the spring by means oftank model analysis. In this evaluation, not only increasing of impervious land cover but also diminish of reduced leakage fromthe water main are take into consideration.
From stable water isotopes measurement, it is suggested that leakage from the water main recharges the spring. From Detailed
Digital Information (10m Grid Land Use), it was determined that land cover/land use of the subject area has remained unchanged
since the 1980’s so that it does not effect spring discharge. We developed a model that represents discharge from the spring basedon the observation. The model was calibrated using data from 2012-2013 and validated using data from 2009-2012. We used themodel to simulate the discharge for 1998-2013 and specifically investigated the impacts of impervious land cover fraction andwater main leakage on long-term trends in the spring discharge. If we take into account reduced leakage from the water main,then discharge is decreasing over time.
Keywords: spring, Tokyo wards area, impervious land cover fraction, water main leakage, tank model

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AHW25-04

Room:101B

Time:May 27 15:05-15:20

Three-dimensional mapping of groundwater flow system in Osaka Basin based on thedatabase of water chemistry
SHINTANI, Tsuyoshi1∗ ; MASUDA, Harue1 ; NEMOTO, Tatsuya1 ; MASUMOTO, Shinji1 ; MITAMURA, Muneki1 ;MORIKAWA, Noritoshi2 ; YASUHARA, Masaya2 ; MARUI, Atsunao2
1Graduate school of science osaka city university, 2 National Institute of Advanced Industrial Science and Technology

Osaka Basin is a large reservoir of groundwater resources, which can be used for various applications as industrial and domestic
water resources. However, the uptake of groundwater has been strictly regulated in the center of Osaka Basin since 1960s to
avoid geogenic disasters such as land subsidence, which actively occurred in the period of rapid economic growth. The land
subsidence has stopped since 1970s because of the regulation, and groundwater has not been extensively used for more than
three decades. However, the uptake of groundwater has been a threat again due to increasing consumption of groundwater for
private water supplies since 2000s. Depths of private wells for industries, hospitals, etc., are mostly from 100 to 300m from theground surface, where the shrinking clay layers severely occurred. Because those groundwaters have not been used for long time,present water chemistry is not well documented.
In this study, groundwaters mainly sampled from the wells between 100 and 300m depths were studied for the stable hydrogenand oxygen isotope ratios and major chemical components to estimate the origins of groundwaters. Combining the results ofthis study and previous studies, three-dimensional mapping of groundwater geochemistry was drawn to discuss the groundwaterflow system of the basin and the effect of the land subsidence to the present groundwater geochemistry. Aquifers of groundwater
were classified by geological information including marine clay layers. This study was successful to visualize the groundwaterchemistry as three-dimensional maps, which clearly show the following features of groundwater chemistry.
Hydrogen and oxygen isotope ratios of the groundwater ≤ 100m depths increased from mountainous areas to the center ofplain, and the origin of these groundwaters were local meteoric water. In the western plain of Uemachi plateau, of which altitude
is below sea level, the stable isotope ratios of groundwaters (δ 2 H: -40 ‰ ∼, δ 18 O: -5 ‰ ∼) are larger than those of local meteoricwater (δ 2 H: -45 ‰ ∼-40 ‰, δ 18 O: -7 ‰ ∼-6 ‰), due to mixing with seawater. Thus, the seawater invaded into the aquifers ofthese areas, especially those between marine clay layers Ma12 and Ma9.
The stable isotope ratios of the groundwater were low (δ 2 H: ∼-55 ‰, δ 18 O: ∼-8 ‰) in the deeper aquifers than the Ma9.
Slightly lower isotope ratios of the groundwaters than those of local meteoric water with diluted Na-HCO3 type chemistrysuggested that the groundwater contained squeezed pore water from the overlying clay layers. It would be the evidence ofexcessive wage of groundwater when the land subsidence actively occurred.

Keywords: groundwater, isotope

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AHW25-05

Room:101B

Time:May 27 15:20-15:35

Removal of very fine oil particles from produced water by microbubble flotation in conjunction with coagulation technic
KOJIMA, Keisuke1∗ ; TASAKI, Masaharu1 ; OKAMURA, Kazuo2 ; MARK N., Sueyoshi1 ;RASHID S., Al-maamari3
1SHIMIZU CORPORATION, 2 TECNET Co. Ltd, 3 Sultan Qaboos University

During the oil production process, oily waste water is coproduced at a rate several times that of oil. This water is known as
produced water. Most produced water requires treatment to prevent groundwater contamination because it contains very fineoil particles as dispersed and dissolved oil, which are very difficult to separate by gravity separation. It also contains heavy
metals, boron, corrosive fluids such as H2 S, and other chemicals. The treatment and disposal of produced water is a significant
operating expense for oil and gas companies. Therefore, treatment levels and technologies are selected based on disposal methodor reutilization objectives, environmental impacts, economics, and other such factors.
A 50 m3 /day capacity pilot plant was designed, fabricated, and utilized to conduct produced water treatment trials in Oman.
Pilot treatment trials of produced water from three different oilfields in Oman were carried out by nitrogen microbubble flotationin conjunction with coagulation/flocculation. Filtration and adsorption treatment processes were tested as advanced process forreutilization objectives.
Oil concentration in one of the produced waters was reduced to below the Omani standard for re-use, through microbubble
flotation combined with coagulation/flocculation treatment. Oil concentrations in the other two produced waters, which had
higher-initial concentrations, were reduced to below the Omani standard for marine discharge. With additional adsorption treatment, these concentrations were further reduced of the level of the re-use standard as well.
Additionally, aeration treatment was effective for removal of sulfur compounds such as sulfide from produced water.

Keywords: produced water, microbubble flotation, coagulation/flocculation, oil removal

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AHW25-06

Room:101B

Time:May 27 15:35-15:55

Utilization and environmental suitability of excavated and recovered soils
KATSUMI, Takeshi1∗
1

Graduate School of Global Environmental Studies

Soil excavation and reclamation are fundamental steps of infrastructure development. For the re-development of urbanized areas, where the use of underground space is unavoidable since finding new land space is usually difficult, few construction works
for infrastructure can be possible without excavation. As a result, excavated surplus soils are generated in large quantities. Management of such excavated soils discharged through construction works is therefore an important consideration in geotechnicaland geoenvironmental engineering. Reuse of excavated soils either at the generating sites or at different places has been promoted, because disposal of unusable soils at landfill sites should be minimized due to the limited capacity of landfills. Limitationof available natural resources, as well as land spaces for landfills, has strongly promoted reuse of materials in Japan. Reuse ofmaterials in construction works has particularly attracted a great attention because of the large capacity of application as well as
the large generation of by-products including excavated soils. Since the establishment of Soil Contamination Countermeasures
Law in 2002, natural contamination which may be contained in such excavated soils has been a concern, while proper method toevaluate the environmental suitability assessment is still under discussion. The 2011 East Japan earthquake and tsunami which
occurred on March 11 generated a large quantity of disaster wastes and tsunami deposits which requires proper treatment andutilization. Use of the recovered soils obtained from disaster debris has been an issue in the affected area. In this presentation,these issues are presented.
Keywords: Excavated soil, Heavy metal, Geoenvironment

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