著者

Moono SHIN Tomijiro KUBOTA Koji HAMADA Tadayoshi HITOMI Takeshi OTA

出版者

日本水環境学会

雑誌

Journal of Water and Environment Technology (ISSN:13482165)

巻号頁・発行日

vol.13, no.5, pp.383-394, 2015 (Released:2015-10-10)

参考文献数

16

被引用文献数

7

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Radioactive contamination resulting from the Tokyo Electric Power Company Fukushima Daiichi Nuclear Power Station disaster following the Great East Japan earthquake and tsunami on March 11, 2011, has affected large areas of land in Fukushima, Japan. At present, agriculture has been limited to some areas, and there are concerns that radioactive substances carried by rainwater might contaminate water bodies such as ponds and rivers. In order to resume safe agricultural activities, evaluating the dynamics of radioactive substances in agricultural water is essential. In this study, we measured the concentration and analyzed the impact of radioactive cesium in irrigation water on rice in five districts having limited residential population. Further, we analyzed the radioactive cesium balance and soil samples from decontaminated paddy fields. The main findings of the study are (1) radioactive cesium in agricultural water was mainly in suspended form at the experimental locations within the 40 km zone; (2) most of the radioactive cesium in the irrigation water was accumulated in the paddy field, but radioactive cesium in irrigation water had limited impact on brown rice cultivation; and (3) continual monitoring of areas with radiation levels higher than those recorded in this study is recommended.

著者

Tatsuru KAMEI Dai NAITOH Wilawan KHANITCHAIDECHA Futaba KAZAMA

出版者

日本水環境学会

雑誌

Journal of Water and Environment Technology (ISSN:13482165)

巻号頁・発行日

vol.13, no.2, pp.167-178, 2015 (Released:2015-04-10)

参考文献数

30

被引用文献数

1 5

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Groundwater is often contaminated by ammonium and nitrate, causing problems in developing countries such as Thailand and Nepal. Therefore, development of new methods for removing contaminants from groundwater is necessary. In this study, we investigated the effectiveness of a new treatment system for simultaneous removal of ammonium and nitrate by anaerobic ammonium oxidation (ANAMMOX) and hydrogenotrophic denitrification. Enriched ANAMMOX sludge was cultivated under two conditions (20 mL/min hydrogen gas flow rate to investigate the effectiveness of ANAMMOX and hydrogenotrophic denitrification; and 60 mL/min hydrogen gas flow rate to examine the effect of the presence of nitrite on the activities of both microbes). Simultaneous removal of ammonium and nitrate was successfully detected using the former condition, and 95% of ammonium and 90% of nitrate were successfully removed. Additionally, the maximum nitrogen removal rate was 0.25 kg-N/m3/d, and 89% of the total dissolved nitrogen was removed. Using the latter condition, increases in nitrite removal were observed only during the supply of hydrogen gas. These results showed that a hydrogenotrophic denitrifier coexisted with ANAMMOX bacteria in our enriched sludge and that ANAMMOX and hydrogenotrophic denitrification removed ammonium and nitrate simultaneously. Therefore, this method may represent a novel efficient technique for the removal of contaminants from groundwater.

著者

渡辺 直

出版者

日本水環境学会

雑誌

水環境学会誌 = Journal of Japan Society on Water Environment (ISSN:09168958)

巻号頁・発行日

vol.18, no.12, pp.932-937, 1995-12-10

参考文献数

45

被引用文献数

1

著者

高村 典子

出版者

日本水環境学会

雑誌

水環境学会誌 = Journal of Japan Society on Water Environment (ISSN:09168958)

巻号頁・発行日

vol.18, no.12, pp.948-953, 1995-12-10

参考文献数

20

著者

Ryo Honda Yuta Teraoka Mana Noguchi Sen Yang

出版者

日本水環境学会

雑誌

Journal of Water and Environment Technology (ISSN:13482165)

巻号頁・発行日

vol.15, no.1, pp.1-11, 2017 (Released:2017-02-10)

参考文献数

27

被引用文献数

23

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Treated sewage is a promising source of nitrogen and phosphorus in microalgae biomass production for carbon-neutral biofuel and chemical products. In this study, Chlorella vulgaris was continuously cultivated in membrane photobioreactors (MPBRs) under short hydraulic retention times (HRTs) and with different numbers of submerged membrane modules to investigate potential microalgae productivity when treated sewage was used as a nutrient source. Microalgae biomass concentrations were independent of HRT in MPBRs with one membrane module owing to microalgae biomass deposition on the membrane. Installation of an additional submerged membrane module effectively reduced deposition on the submerged membrane, resulting in increased microalgae biomass concentration and volumetric productivity. Growth kinetics suggested that HRT is the essential parameter influencing the volumetric productivity of microalgae under nutrient-limited conditions, and that optimization of the biomass concentration, which depends on the surface/volume ratio of the photobioreactor and initial light intensity, is critical to maximization of the volumetric productivity under light-limited conditions.

著者

Rei YAMASHITA Michio MURAKAMI Yuichi IWASAKI Nao SHIBAYAMA Keisuke SUEKI Mahua SAHA Goro MOURI Soulichan LAMXAY Haechong O Yukio KOIBUCHI Hideshige TAKADA

出版者

日本水環境学会

雑誌

Journal of Water and Environment Technology (ISSN:13482165)

巻号頁・発行日

vol.13, no.2, pp.179-194, 2015 (Released:2015-04-10)

参考文献数

49

被引用文献数

3 15

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The release of radiocesium from the Fukushima Dai-ichi Nuclear Power Plant caused environmental contamination. We analyzed sources, behavior, and temporal trends of radiocesium by 1-year monitoring in an urban river, the Ohori River. The concentrations of 137Cs in both particulate and dissolved phases decreased to ~ 16% within 1 year. The partition coefficient in dry weather was estimated to be 3.2 × 104 L/kg. 137Cs concentrations in the particulate phase were higher during wet weather than during dry weather on the basis of both suspended solids (SS) weight and liquid volume. The ratios of 137Cs concentration to deposited 137Cs in the Ohori River (e.g., composite: 0.26 m2/kg-SS in June - July 2012) were higher than those in the Abukuma River, probably because of differences in land use. Source analysis by a chemical mass balance method showed that 22% of 137Cs came from river water in dry weather, 39% from river sediments, and 39% from road dust highlighting urban surface deposits such as road dust as major sources of 137Cs in the river water even 2 years after the accident, and that the wash-off of these deposits increased the 137Cs concentration in the river during wet weather.

著者

Pokchat CHUTIVISUT Wiboonluk PUNGRASMI Sorawit POWTONGSOOK

出版者

日本水環境学会

雑誌

Journal of Water and Environment Technology (ISSN:13482165)

巻号頁・発行日

vol.12, no.4, pp.347-356, 2014 (Released:2014-08-10)

参考文献数

28

被引用文献数

1 12

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Suspended organic sludge from freshwater and biofloc Nile tilapia systems were examined for the presence of denitrifying and dissimilatory nitrate reduction to ammonium (DNRA) activities under nitrate and sulfide stimulation. Initial nitrate concentrations at 25 and 100 mg NO3--N/L were added to the freshwater sludge and biofloc samples to simulate low and high nitrate levels that are normally found in aquaculture systems. The results showed that freshwater sludge and biofloc both had denitrifying activity immediately after nitrate addition. However, ammonium accumulated in the biofloc reactors but not in the freshwater reactors, indicating the activity of DNRA in the high C/N biofloc particles. The influence of sulfide on nitrate reduction was also studied by adding different concentrations of sulfide along with 100 mg NO3--N/L. The results showed that elevated sulfide concentrations partially inhibited denitrification in the freshwater sludge and caused nitrite and ammonium accumulation, in which ammonium formation was probably responsible by DNRA activity. In sulfide-added biofloc reactors, ammonium accumulated at the same level as found in the biofloc reactors without sulfide. Therefore, DNRA bacteria residing in the biofloc aquaculture system were more likely to be heterotrophs that did not use sulfide as their electron donor.

著者

Izarul MACHDAR Muhammad FAISAL

出版者

日本水環境学会

雑誌

Journal of Water and Environment Technology (ISSN:13482165)

巻号頁・発行日

vol.9, no.1, pp.47-52, 2011 (Released:2011-03-31)

参考文献数

9

被引用文献数

2 3

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An oil palm fiber module has been developed to modify a down-flow hanging sponge (DHS) reactor module. The objective of the proposed system is to improve two existing DHS variants of post-treatment unit for UASB treating domestic wastewater, i.e. cube-type and curtain-type sponge as domestic wastewater treatment system for developing countries. This paper describes the potential of oil palm fiber-based DHS (PF-DHS) configuration for sewage treatment. Feasibility of the PF-DHS reactor was evaluated by conducting a six-month continuous operation using actual sewage as feed. The system has been verified to have an excellent organic removal performance achieving 67% of unfiltered COD removal, and nearly perfect SS removal at the HRT of 2 h. It was observed that the organic removal rate was approximately 2.64 kg COD/m3 per day. The result recommended that the proposed PF-DHS reactor would be a promising system to alter sponge-based DHS for domestic wastewater treatment system in developing countries.

著者

蒔苗 靖子 渡部 徹 大村 達夫 遠藤 銀朗

出版者

日本水環境学会

雑誌

水環境学会誌 = Journal of Japan Society on Water Environment (ISSN:09168958)

巻号頁・発行日

vol.23, no.12, pp.771-777, 2000-12-10

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Outbreaks of infectious diseases by new pathogenic microorganisms through water utilization have been reported in recent years. Especially, Legionnaires' disease has been recognized as a serious problem in modern societies since a high concentration of <i>Legionella pneumophila</i> often exist in water environment (such as cooling tower, bath water, recreational water) close to human activities. In this study, the quantitative detection method (colony-hybridization) for <i>L. pneumophila</i> was developed by combining the hybridization with the plate culture method. The developed detection method enabled <i>L. pneumophila</i> to be enumerated in various water samples. It was possible to quantify <i>L. pneumophila</i> without interferences of other bacteria by this method in case that the number of total coliforms on the plate was less than 10³ CFU.

著者

臼井 恵次 進藤 晴夫 丸本 卓哉 岸野 拓男

出版者

日本水環境学会

雑誌

水環境学会誌 (ISSN:09168958)

巻号頁・発行日

vol.17, no.9, pp.596-599, 1994

被引用文献数

2 1

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A release of phosphorus from calcium phosphate, iron(III) phosphate, and aluminum phosphate owing to the complex formation of their metals with fulvic acid was examined. Fulvic acid was extracted from lake sediments and treated with Amberlite XAD-8 resin. The non-adsorbed fraction of fulvic acid on the resin, which has highly Cu2+-complexing capacity, was used in this study, because the adsorbed fraction has only little Cu2+-complexing capacity as reported in our previous paper. The non-adsorbed fraction was able to release phosphorus from calcium phosphate, but not from iron(III) phosphate, and aluminum phosphate. The application of X-ray analysis to the calcium phosphate indicated that the major component is hydroxyapatite. The stability constant of the Cu2+-fractionated fulvic acid was determined to be 2×10(5) (log K=5.3) and the average molecular weight of the fulvic acid was 1,026.

著者

臼井 恵次 岸野 拓男 東 俊雄 進藤 晴夫 丸本 卓哉

出版者

日本水環境学会

雑誌

水環境学会誌 (ISSN:09168958)

巻号頁・発行日

vol.16, no.10, pp.690-695, 1993

被引用文献数

3 3

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Fulvic acid extracted from lake sediments was treated with Amberlite XAD-2 and XAD-8 resins. The metal complexing ability of the fulvic acid was measured at pH 6.0 with a Cu2+ titration method, in which free Cu2+ was determined with an ion selective electrode. A two binding site model, in which there are two kinds of the molecules having strong and weak complexing ability and they complex with metal ion at the ratio of 1:1, was employed for the determination of the stability constant and complexing capacity of the fulvic acid, because the hyperbolic approxmation could apply to the Scatchard plot of the found values. The stability constants of the fulvic acids having strong complexing ability and weak complexing ability were in the range of 6.33-7.12 and 4.35-4.66, respectively. Both colorless fractions of the fulvic acid which were not adsorbed on XAD-2 and XAD-8 resins had such a high complexing ability as 44 and 32 μmol・g-1, respectively. On the other hand, both colored fractions of the fulvic acid which were adsobed on the resins had only little complexing capacity.