M. Bahreinimotlagh, K. Kawanisi, A. Kavousi, R. Roozbahani, M. Abbasi, M. B. A. Sawaf
Fluvial Acoustic Tomography System (FATS) as an advanced technology acquires continuous streamflow data in rivers and estuaries even during floods. However, the acoustic signals are dramatically attenuated by suspending sediments which this problem is a new field of study. In this study, we propose a new equation to estimate the maximum applicable measurement distances ( MAMD s). It is based on the cross-sectional suspended sediment concentration ( ) and the particle sizes on the 30-kHz FATS. Our study results show that MAMD might be 2,380 m in the clear water. Moreover, the streamflow monitoring can be perfectly done while is less than 12.67 kg/m 3 with the particle radii of 3 μm, when the horizontal distance between two acoustic stations is 100 m. Also, the acoustic signals are not decayed if the particle radii equal to 20 mm and the maximum is 6.6 kg/m 3 . This study highlights the performance of FATS in the presence of high and provides a better perspective of applying FATS in different rivers with high variability of .
{"title":"Influence of Suspended Sediment Concentration and Particle Sizes on the Sound Attenuation of the Fluvial Acoustic Tomography Technique","authors":"M. Bahreinimotlagh, K. Kawanisi, A. Kavousi, R. Roozbahani, M. Abbasi, M. B. A. Sawaf","doi":"10.2965/jwet.20-024","DOIUrl":"https://doi.org/10.2965/jwet.20-024","url":null,"abstract":"Fluvial Acoustic Tomography System (FATS) as an advanced technology acquires continuous streamflow data in rivers and estuaries even during floods. However, the acoustic signals are dramatically attenuated by suspending sediments which this problem is a new field of study. In this study, we propose a new equation to estimate the maximum applicable measurement distances ( MAMD s). It is based on the cross-sectional suspended sediment concentration ( <SSC> ) and the particle sizes on the 30-kHz FATS. Our study results show that MAMD might be 2,380 m in the clear water. Moreover, the streamflow monitoring can be perfectly done while <SSC> is less than 12.67 kg/m 3 with the particle radii of 3 μm, when the horizontal distance between two acoustic stations is 100 m. Also, the acoustic signals are not decayed if the particle radii equal to 20 mm and the maximum <SSC> is 6.6 kg/m 3 . This study highlights the performance of FATS in the presence of high <SSC> and provides a better perspective of applying FATS in different rivers with high variability of <SSC> .","PeriodicalId":17480,"journal":{"name":"Journal of Water and Environment Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69263170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Kuroda, Yoshida Anri, Obuchi Emi, Kawabata Hironoshin, T. Arai
A novel fluidization backwash method by the air-water bubbly flow with air bubbles of various sizes has been proposed for rapid filters. The backwash efficiency is closely related to the bubble wake motion. Bubble coalescence, bed contraction and jet generation caused by the motion of air bubble wakes strikingly enhance the discharge of retained sludge. The effect of the bubble wakes on the backwash efficiency is ensured by controlling the fluidizing condition which is easily identified visually. The size of air bubbles should be controlled properly, and the air bubble size at the dense bed surface must be within several centimeters to prevent the loss of filter media particles from filter beds. The backwash efficiency of the filter bed achieved 94% in average by optimizing the air bubble size in the air-water bubbly flow. The air-water bubbly flow backwash method was also applied to a self-backwash filter where the backwash flow rate depends on an elevated water tank, and the backwash efficiency was as high as that for the constant flow rate backwash method.
{"title":"The Fluidization Backwash Method of Filter Beds by Air-water Bubbly Flow","authors":"M. Kuroda, Yoshida Anri, Obuchi Emi, Kawabata Hironoshin, T. Arai","doi":"10.2965/jwet.20-014","DOIUrl":"https://doi.org/10.2965/jwet.20-014","url":null,"abstract":"A novel fluidization backwash method by the air-water bubbly flow with air bubbles of various sizes has been proposed for rapid filters. The backwash efficiency is closely related to the bubble wake motion. Bubble coalescence, bed contraction and jet generation caused by the motion of air bubble wakes strikingly enhance the discharge of retained sludge. The effect of the bubble wakes on the backwash efficiency is ensured by controlling the fluidizing condition which is easily identified visually. The size of air bubbles should be controlled properly, and the air bubble size at the dense bed surface must be within several centimeters to prevent the loss of filter media particles from filter beds. The backwash efficiency of the filter bed achieved 94% in average by optimizing the air bubble size in the air-water bubbly flow. The air-water bubbly flow backwash method was also applied to a self-backwash filter where the backwash flow rate depends on an elevated water tank, and the backwash efficiency was as high as that for the constant flow rate backwash method.","PeriodicalId":17480,"journal":{"name":"Journal of Water and Environment Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69263576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yuta Fujii, K. Mitsuka, Hiroki Ogata, D. Inoue, M. Ike
To evaluate the effectiveness of gluconate as a potential hydrogen donor for reductive dechlorina tion of chloroethenes, we developed a trichloroethene (TCE)-dechlorinating consortium from chloroethenes-contaminated groundwater containing Dehalococcoides using gluconate as the sole hydrogen donor and characterized its chloroethenes-dechlorinating performance and microbial com munity composition. After repeated subculturing, we successfully developed a microbial consortium with gluconate, which showed consistent dechlorination of TCE to vinyl chloride (VC), resulting in subsequent disappearance of VC. The resultant consortium could dechlorinate 24 μmol/L TCE to VC and eliminate VC within 20 days, which was similar to or slightly longer than the required time when other hydrogen donors such as lactate or methanol were used. These results indicate that gluconate can be an effective hydrogen donor for reductive dechlorination of chloroethenes. Real-time PCR and terminal restriction fragment length polymorphism analyses of bacterial and archaeal populations revealed the establishment of a stable microbial community in the developed consortium. In addition, 16S rRNA amplicon sequencing revealed that Trichococcus and Malikia were the predominant taxa, whereas Dehalococcoides and other dechlorinating populations were minor. Our results infer that the use of gluconate as a hydrogen donor established a distinctive microbial community compared with enriched consortia developed with other hydrogen donors.
{"title":"Development and Characterization of a Chloroethenes-Dechlorinating Consortium Using Gluconate as a Hydrogen Donor","authors":"Yuta Fujii, K. Mitsuka, Hiroki Ogata, D. Inoue, M. Ike","doi":"10.2965/jwet.20-016","DOIUrl":"https://doi.org/10.2965/jwet.20-016","url":null,"abstract":"To evaluate the effectiveness of gluconate as a potential hydrogen donor for reductive dechlorina tion of chloroethenes, we developed a trichloroethene (TCE)-dechlorinating consortium from chloroethenes-contaminated groundwater containing Dehalococcoides using gluconate as the sole hydrogen donor and characterized its chloroethenes-dechlorinating performance and microbial com munity composition. After repeated subculturing, we successfully developed a microbial consortium with gluconate, which showed consistent dechlorination of TCE to vinyl chloride (VC), resulting in subsequent disappearance of VC. The resultant consortium could dechlorinate 24 μmol/L TCE to VC and eliminate VC within 20 days, which was similar to or slightly longer than the required time when other hydrogen donors such as lactate or methanol were used. These results indicate that gluconate can be an effective hydrogen donor for reductive dechlorination of chloroethenes. Real-time PCR and terminal restriction fragment length polymorphism analyses of bacterial and archaeal populations revealed the establishment of a stable microbial community in the developed consortium. In addition, 16S rRNA amplicon sequencing revealed that Trichococcus and Malikia were the predominant taxa, whereas Dehalococcoides and other dechlorinating populations were minor. Our results infer that the use of gluconate as a hydrogen donor established a distinctive microbial community compared with enriched consortia developed with other hydrogen donors.","PeriodicalId":17480,"journal":{"name":"Journal of Water and Environment Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69263593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. Berrebaan, L. Montassir, M. Alami, M. Saadallah, H. Bessi
This study aims to assess the performance of five municipal wastewater treatment plants (MWWTPs) from different locations in Morocco using chemical analyses and bioassays. The toxicity assessments were based on the chronic algal growth inhibition using the green microalgae Pseudokirchneriella subcapitata and acute immobilization using the crustacean Daphnia magna. The physicochemical results show that the effluents were mainly polluted with organic and nitrogenous compounds as indicated by higher values of chemical oxygen demand (COD), biochemical oxygen demand (BOD), as well as total nitrogen (TN). The promotion of algal growth was detected in all raw samples, except MWWTP2, MWWTP3, and MWWTP4 influents, in which, the half maximal effective concentration after 72 hours (EC50-72 h) were 61.83% v/v, 53.4% v/v and 87.46% v/v, respectively. Meanwhile, all treated effluents stimulate the algal growth, except MWWTP2 effluent (EC50-72 h: 55.1% v/v). Furthermore, the untreated samples display immobilizations towards Daphnia magna. The EC50-48 h values were ranked from 7.30% v/v to 79.76% v/v. However, only two effluents from MWWTP1 and MWWTP2 exhibit acute toxicities (the EC50-48 h were 45.80% v/v and 41% v/v, respectively). The Spearman correlation coefficients indicate strong positive correspondences between EC50-48 h and COD (r = 0.840, p < 0.05), TN (r = 0.731, p < 0.05), total phosphorus (TP) (r = 0.730, p < 0.05), and PO4 (r = 0.792, p < 0.05).
这项研究的目的是利用化学分析和生物测定法评估来自摩洛哥不同地点的五个城市污水处理厂(MWWTPs)的性能。毒性评价是基于绿色微藻对藻类生长的慢性抑制作用和甲壳类动物大水蚤的急性固定作用。理化分析结果表明，污水主要受有机和氮化合物污染，化学需氧量(COD)、生化需氧量(BOD)和总氮(TN)均较高。除MWWTP2、MWWTP3和MWWTP4外，所有原料样品均有促进藻类生长的作用，其中72 h后(EC50-72 h)的一半最大有效浓度分别为61.83% v/v、53.4% v/v和87.46% v/v。同时，除MWWTP2出水(EC50-72 h: 55.1% v/v)外，所有处理后的出水均能促进藻类生长。此外，未经处理的样品显示对大水蚤的固定作用。EC50-48 h值从7.30% v/v到79.76% v/v。然而，MWWTP1和MWWTP2只有两种出水表现出急性毒性(EC50-48 h分别为45.80% v/v和41% v/v)。Spearman相关系数表明，EC50-48 h与COD (r = 0.840, p < 0.05)、TN (r = 0.731, p < 0.05)、TP (r = 0.730, p < 0.05)、PO4 (r = 0.792, p < 0.05)呈极显著正相关。
{"title":"The Integration of Bioanalytical Approaches in the Assessment of Municipal Wastewater Treatment Plant Performances","authors":"I. Berrebaan, L. Montassir, M. Alami, M. Saadallah, H. Bessi","doi":"10.2965/jwet.18-092","DOIUrl":"https://doi.org/10.2965/jwet.18-092","url":null,"abstract":"This study aims to assess the performance of five municipal wastewater treatment plants (MWWTPs) from different locations in Morocco using chemical analyses and bioassays. The toxicity assessments were based on the chronic algal growth inhibition using the green microalgae Pseudokirchneriella subcapitata and acute immobilization using the crustacean Daphnia magna. The physicochemical results show that the effluents were mainly polluted with organic and nitrogenous compounds as indicated by higher values of chemical oxygen demand (COD), biochemical oxygen demand (BOD), as well as total nitrogen (TN). The promotion of algal growth was detected in all raw samples, except MWWTP2, MWWTP3, and MWWTP4 influents, in which, the half maximal effective concentration after 72 hours (EC50-72 h) were 61.83% v/v, 53.4% v/v and 87.46% v/v, respectively. Meanwhile, all treated effluents stimulate the algal growth, except MWWTP2 effluent (EC50-72 h: 55.1% v/v). Furthermore, the untreated samples display immobilizations towards Daphnia magna. The EC50-48 h values were ranked from 7.30% v/v to 79.76% v/v. However, only two effluents from MWWTP1 and MWWTP2 exhibit acute toxicities (the EC50-48 h were 45.80% v/v and 41% v/v, respectively). The Spearman correlation coefficients indicate strong positive correspondences between EC50-48 h and COD (r = 0.840, p < 0.05), TN (r = 0.731, p < 0.05), total phosphorus (TP) (r = 0.730, p < 0.05), and PO4 (r = 0.792, p < 0.05).","PeriodicalId":17480,"journal":{"name":"Journal of Water and Environment Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69262236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Daisuke Yumioka, T. Hama, K. Kitamura, S. Hatate, Hiroaki Ito, Y. Kawagoshi
High concentration (more than 1.0 mgP/L) of phosphorus was detected in groundwater in Aso caldera, Kumamoto. The fact indicates phosphorus can be transported by groundwater flows. The objective of this study is to clarify the characteristics of paddy soil (Andosol) in phosphorus adsorption process. Adsorption capacity of the Andosol was evaluated by continuously-flowing system using the soil column. In addition, soil phosphorus was categorized into five fractions; water-extractable phosphorus (Water-P), phosphorus extracted by sodium bicarbonate and sodium dithionate (DB-P), phosphorus extracted by sodium hydroxide (NaOH-P), phosphorus extracted by hydrochloric acid (HCl-P) and residual phosphorus (Res-P). As a result, it is confirmed that the flow rate of water is an important factor to control the phosphorus adsorption by the Andosol. The lower the flow rate is, the more phosphorus is adsorbed on the upstream soil. On the other hand, when the flow rate was high, phosphorus was evenly distributed in column soil. In addition, the fraction of NaOH-P accounted for 52% of the adsorbed phosphorus, suggesting that NaOH-P is the most important fraction which controls phosphorus adsorption to Andosol.
{"title":"Adsorption of Phosphorus Infiltrating Andosol in Aso Caldera, Kumamoto","authors":"Daisuke Yumioka, T. Hama, K. Kitamura, S. Hatate, Hiroaki Ito, Y. Kawagoshi","doi":"10.2965/jwet.19-068","DOIUrl":"https://doi.org/10.2965/jwet.19-068","url":null,"abstract":"High concentration (more than 1.0 mgP/L) of phosphorus was detected in groundwater in Aso caldera, Kumamoto. The fact indicates phosphorus can be transported by groundwater flows. The objective of this study is to clarify the characteristics of paddy soil (Andosol) in phosphorus adsorption process. Adsorption capacity of the Andosol was evaluated by continuously-flowing system using the soil column. In addition, soil phosphorus was categorized into five fractions; water-extractable phosphorus (Water-P), phosphorus extracted by sodium bicarbonate and sodium dithionate (DB-P), phosphorus extracted by sodium hydroxide (NaOH-P), phosphorus extracted by hydrochloric acid (HCl-P) and residual phosphorus (Res-P). As a result, it is confirmed that the flow rate of water is an important factor to control the phosphorus adsorption by the Andosol. The lower the flow rate is, the more phosphorus is adsorbed on the upstream soil. On the other hand, when the flow rate was high, phosphorus was evenly distributed in column soil. In addition, the fraction of NaOH-P accounted for 52% of the adsorbed phosphorus, suggesting that NaOH-P is the most important fraction which controls phosphorus adsorption to Andosol.","PeriodicalId":17480,"journal":{"name":"Journal of Water and Environment Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69262863","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Takemoto, K. Mitsuhara, M. Tabuchi, Yuka Segawa, Daiya Bamba, T. Ohta
The periostracum of corbicula clams is a unique outermost organic layer secreted from the inner surface of the outer mantle. It records the environmental history of corbicula clams which inhabited Lake Biwa. Two types of corbicula clams, yellowish and blackish shells, were studied with X-ray fluorescence element mapping and S, Fe and Mn K-edge X-ray absorption fine structure (XAFS) spectroscopy. It was revealed that the blackish shells grow in the more reducing environment than the yellowish ones. Main constituent of the periostracum is protein-based material, such as cysteine and methionine. The blackish shells contain much higher amount of Fe and Mn impurities. Fe was accumulated as FeOOH along the growth lines. Sulfur exists exclusively as organic molecules with the functional groups of thiol (-SH), which is oxidized to form disulfide (-SS-) by exposure to the oxidizing environment.
蛤的骨膜是一种独特的最外层的有机层，分泌自外地幔的内表面。它记录了琵琶湖蛤的环境历史。采用x射线荧光元素图谱和S、Fe、Mn K-edge x射线吸收精细结构(XAFS)光谱对黄、黑两种蛤壳进行了研究。结果表明，黑贝壳比黄贝壳生长在还原性更强的环境中。骨膜的主要成分是蛋白质基物质，如半胱氨酸和蛋氨酸。黑色的贝壳含有大量的铁和锰杂质。铁以FeOOH的形式沿生长线积累。硫仅以具有巯基(- sh)的有机分子形式存在，巯基在氧化环境中被氧化形成二硫化物(- ss -)。
{"title":"Chemical State Analysis of the Periostracum in the Corbicula Clam Hatched in Lake Biwa","authors":"K. Takemoto, K. Mitsuhara, M. Tabuchi, Yuka Segawa, Daiya Bamba, T. Ohta","doi":"10.2965/jwet.19-072","DOIUrl":"https://doi.org/10.2965/jwet.19-072","url":null,"abstract":"The periostracum of corbicula clams is a unique outermost organic layer secreted from the inner surface of the outer mantle. It records the environmental history of corbicula clams which inhabited Lake Biwa. Two types of corbicula clams, yellowish and blackish shells, were studied with X-ray fluorescence element mapping and S, Fe and Mn K-edge X-ray absorption fine structure (XAFS) spectroscopy. It was revealed that the blackish shells grow in the more reducing environment than the yellowish ones. Main constituent of the periostracum is protein-based material, such as cysteine and methionine. The blackish shells contain much higher amount of Fe and Mn impurities. Fe was accumulated as FeOOH along the growth lines. Sulfur exists exclusively as organic molecules with the functional groups of thiol (-SH), which is oxidized to form disulfide (-SS-) by exposure to the oxidizing environment.","PeriodicalId":17480,"journal":{"name":"Journal of Water and Environment Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69262972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Q. H. Nguyen, T. Watari, Takashi Yamaguchi, Y. Kawamura, H. Suematsu, J. P. Wiff, K. Niihara, T. Nakayama
This paper proposes the utilization of a nanosecond pulsed (NSP) power supply in the electrocoagulation (EC) system for textile wastewater treatment. Four aluminum plates arranged in a monopolarparallel configuration are utilized as electrodes in a 200 ml EC reactor. Chemical oxygen demand (COD) and specific energy consumption (SEC) are utilized to characterize the performance of NSPpowered EC. A DC power supply is considered as a benchmark. Field-emission scanning electron microscopy, X-ray diffraction, and energy-dispersive spectroscopy are utilized to characterize flocs. The results reveal that a maximum COD removal efficiency of 77% can be achieved by utilizing NSP power, while a value of only 60% can be achieved by utilizing DC power. Additionally, NSP power consumes at least 24% less energy than DC power at a similar COD removal efficiency. The utilization of NSP power for textile wastewater treatment allows for high COD removal efficiency with a significantly lower SEC compared to traditional DC-powered EC. It is believed that the low SEC exhibited by NSP power could be useful for promoting the utilization of EC for wastewater treatment and could contribute to the reduction of the carbon footprint of this process.
{"title":"Comparison between Nanosecond Pulse and Direct Current Electrocoagulation for Textile Wastewater Treatment","authors":"Q. H. Nguyen, T. Watari, Takashi Yamaguchi, Y. Kawamura, H. Suematsu, J. P. Wiff, K. Niihara, T. Nakayama","doi":"10.2965/jwet.19-080","DOIUrl":"https://doi.org/10.2965/jwet.19-080","url":null,"abstract":"This paper proposes the utilization of a nanosecond pulsed (NSP) power supply in the electrocoagulation (EC) system for textile wastewater treatment. Four aluminum plates arranged in a monopolarparallel configuration are utilized as electrodes in a 200 ml EC reactor. Chemical oxygen demand (COD) and specific energy consumption (SEC) are utilized to characterize the performance of NSPpowered EC. A DC power supply is considered as a benchmark. Field-emission scanning electron microscopy, X-ray diffraction, and energy-dispersive spectroscopy are utilized to characterize flocs. The results reveal that a maximum COD removal efficiency of 77% can be achieved by utilizing NSP power, while a value of only 60% can be achieved by utilizing DC power. Additionally, NSP power consumes at least 24% less energy than DC power at a similar COD removal efficiency. The utilization of NSP power for textile wastewater treatment allows for high COD removal efficiency with a significantly lower SEC compared to traditional DC-powered EC. It is believed that the low SEC exhibited by NSP power could be useful for promoting the utilization of EC for wastewater treatment and could contribute to the reduction of the carbon footprint of this process.","PeriodicalId":17480,"journal":{"name":"Journal of Water and Environment Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2965/jwet.19-080","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69263053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marine microplastics pollution has been an emerging global threat. This study investigated microplastics pollution in the ‘Seto Inland Sea (SIS)’ and ‘Sea of Japan (SJ)’ surrounded Yamaguchi prefecture areas in Japan. The density separation method was applied to extract microplastics from sea surface sediment and water samples. Polymeric compounds were identified through ATR-FTIR analysis. The average microplastic abundances were 112.57 ± 121.30 items/kg in sediment and 57.46 ± 20.82 items/L in water. Abundance comparisons revealed similar level of pollution in both sea areas and medium to high-level pollution than others around the world. Characterization revealed that fragments and small microplastics (< 1,000 μm) predominated sediments. Fragments and films were major shapes in the SIS sediments while only fragments predominated the SJ sediments. Large microplastics (1,000–5,000 μm) fibers predominated water in all the areas. Transparent microplastics predominated both the sediments and water. Polyethylene, polyvinyl alcohol, and polypropylene were major polymers in sediments while polyethylene terephthalate and polyethylene predominated water. No significant correlations of microplastics abundances and characteristics were observed between sediment and water. Anthropogenic activities and environmental factors were speculated to be the main sources of microplastics in these areas. Overall, this study indicated that microplastics pollution in these marine areas could be an alarming environmental problem.
{"title":"Microplastics Pollution in the Seto Inland Sea and Sea of Japan Surrounded Yamaguchi Prefecture Areas, Japan: Abundance, Characterization and Distribution, and Potential Occurrences","authors":"A. Kabir, M. Sekine, T. Imai, Koichi Yamamoto","doi":"10.2965/jwet.19-127","DOIUrl":"https://doi.org/10.2965/jwet.19-127","url":null,"abstract":"Marine microplastics pollution has been an emerging global threat. This study investigated microplastics pollution in the ‘Seto Inland Sea (SIS)’ and ‘Sea of Japan (SJ)’ surrounded Yamaguchi prefecture areas in Japan. The density separation method was applied to extract microplastics from sea surface sediment and water samples. Polymeric compounds were identified through ATR-FTIR analysis. The average microplastic abundances were 112.57 ± 121.30 items/kg in sediment and 57.46 ± 20.82 items/L in water. Abundance comparisons revealed similar level of pollution in both sea areas and medium to high-level pollution than others around the world. Characterization revealed that fragments and small microplastics (< 1,000 μm) predominated sediments. Fragments and films were major shapes in the SIS sediments while only fragments predominated the SJ sediments. Large microplastics (1,000–5,000 μm) fibers predominated water in all the areas. Transparent microplastics predominated both the sediments and water. Polyethylene, polyvinyl alcohol, and polypropylene were major polymers in sediments while polyethylene terephthalate and polyethylene predominated water. No significant correlations of microplastics abundances and characteristics were observed between sediment and water. Anthropogenic activities and environmental factors were speculated to be the main sources of microplastics in these areas. Overall, this study indicated that microplastics pollution in these marine areas could be an alarming environmental problem.","PeriodicalId":17480,"journal":{"name":"Journal of Water and Environment Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69263123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Eutrophication is a global environmental issue and has been studied for more than 40 years in Atsumi Bay, Aichi Prefecture, Japan. The distribution of nutrients in watersheds and estuaries is strongly influenced by meteorological factors, especially rainfall. Our observations in summer 2010 found that high river discharges during rainfall altered nutrient concentrations throughout the bay, and furthermore resulted in a red tide due to nutrient uptake by phytoplankton. In order to study nutrient dynamics and phytoplankton growth in estuaries, with a focus on the effects of river inputs during rainfall, we developed a depth-averaged two-dimensional ecological model. The model was conceived with the ability to simulate nutrient dynamics, in the form of dissolved nutrient concentrations, and phytoplankton growth throughout an estuary. The model provided reasonable results and agreed well with observed data. Our evaluation showed that the increase in availability of dissolved nutrients and favorable irradiance post-rainfall stimulated production of phytoplankton in the bay, compared to pre-rainfall.
{"title":"Evaluation of Phytoplankton Growth in Atsumi Bay as an Effect of Nutrient Input during Rainfall","authors":"Teuku Mahlil, Takanobu Inoue, K. Yokota","doi":"10.2965/jwet.19-025","DOIUrl":"https://doi.org/10.2965/jwet.19-025","url":null,"abstract":"Eutrophication is a global environmental issue and has been studied for more than 40 years in Atsumi Bay, Aichi Prefecture, Japan. The distribution of nutrients in watersheds and estuaries is strongly influenced by meteorological factors, especially rainfall. Our observations in summer 2010 found that high river discharges during rainfall altered nutrient concentrations throughout the bay, and furthermore resulted in a red tide due to nutrient uptake by phytoplankton. In order to study nutrient dynamics and phytoplankton growth in estuaries, with a focus on the effects of river inputs during rainfall, we developed a depth-averaged two-dimensional ecological model. The model was conceived with the ability to simulate nutrient dynamics, in the form of dissolved nutrient concentrations, and phytoplankton growth throughout an estuary. The model provided reasonable results and agreed well with observed data. Our evaluation showed that the increase in availability of dissolved nutrients and favorable irradiance post-rainfall stimulated production of phytoplankton in the bay, compared to pre-rainfall.","PeriodicalId":17480,"journal":{"name":"Journal of Water and Environment Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2965/jwet.19-025","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69262573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Yoshino, Ayaka Hosoe, T. Hori, M. Hosomi, A. Terada
Excess sludge reduction is a central challenge in wastewater treatment, requiring a cost-effective technology. Here, we report the pilot-scale implementation of two Modified Ludzack-Ettinger (MLE) processes with and without a high-pressure jet device (HPJD) as a sludge reduction method based on physically decomposing bacterial cells in activated sludge. The MLE process with an HPJD (MLE-HPJD) bifurcated the activated sludge return lines and directed them to anoxic and oxic tanks; an HPJD was incorporated in the latter. The operation of both processes by continuous municipal wastewater supply for 111 days demonstrated that HPJD application reduced the cumulative waste activated sludge amount by 56.6% without an increase in the effluent suspended solids (SS) concentration. The two MLE processes displayed comparable removal performances for organic carbon and nitrogen, indicating that sludge solubilization by HPJD does not hinder bacterial activity in activated sludge. A combination of the 16S rRNA gene amplicon sequencing and quantitative fluorescence in situ hybridization (FISH) revealed that microbial community compositions were distinct in the two processes. While still effecting excess sludge reduction, HPJD selectively lowered the relative abundance of filamentous bacteria, potentially causing sludge bulking. Further, the relative abundance and cluster structure of ammonia-oxidizing bacteria (AOB) in the MLE-HPJD and MLE processes were comparable, indicating that the application of HPJD did not impair nitrification performance. Monitoring the eukaryote community by microscopy showed that activated sludge in the MLE-HPJD had a much higher abundance of Protomastigida. Therefore, the MLE-HPJD process is an efficient sludge reduction technology that does not compromise organic carbon and nitrogen removal.
{"title":"Excess Sludge Reduction Using a High-pressure Jet Device via a Modified Ludzack-Ettinger Process: Performance and Microbial Communities","authors":"H. Yoshino, Ayaka Hosoe, T. Hori, M. Hosomi, A. Terada","doi":"10.2965/jwet.19-158","DOIUrl":"https://doi.org/10.2965/jwet.19-158","url":null,"abstract":"Excess sludge reduction is a central challenge in wastewater treatment, requiring a cost-effective technology. Here, we report the pilot-scale implementation of two Modified Ludzack-Ettinger (MLE) processes with and without a high-pressure jet device (HPJD) as a sludge reduction method based on physically decomposing bacterial cells in activated sludge. The MLE process with an HPJD (MLE-HPJD) bifurcated the activated sludge return lines and directed them to anoxic and oxic tanks; an HPJD was incorporated in the latter. The operation of both processes by continuous municipal wastewater supply for 111 days demonstrated that HPJD application reduced the cumulative waste activated sludge amount by 56.6% without an increase in the effluent suspended solids (SS) concentration. The two MLE processes displayed comparable removal performances for organic carbon and nitrogen, indicating that sludge solubilization by HPJD does not hinder bacterial activity in activated sludge. A combination of the 16S rRNA gene amplicon sequencing and quantitative fluorescence in situ hybridization (FISH) revealed that microbial community compositions were distinct in the two processes. While still effecting excess sludge reduction, HPJD selectively lowered the relative abundance of filamentous bacteria, potentially causing sludge bulking. Further, the relative abundance and cluster structure of ammonia-oxidizing bacteria (AOB) in the MLE-HPJD and MLE processes were comparable, indicating that the application of HPJD did not impair nitrification performance. Monitoring the eukaryote community by microscopy showed that activated sludge in the MLE-HPJD had a much higher abundance of Protomastigida. Therefore, the MLE-HPJD process is an efficient sludge reduction technology that does not compromise organic carbon and nitrogen removal.","PeriodicalId":17480,"journal":{"name":"Journal of Water and Environment Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69262709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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