The aim of this study is to investigate the condition of the Ariake Sea, Japan, which has been suffering from severe environmental issues for the past few decades. Water quality data have been generated from several p...The aim of this study is to investigate the condition of the Ariake Sea, Japan, which has been suffering from severe environmental issues for the past few decades. Water quality data have been generated from several points in this area for over 30 years by the Fukuoka, Saga, Kumamoto, and Nagasaki prefectures. In order to understand the characteristics of this sea, principal component analysis (PCA) was utilized using 11 water quality parameters;transparency, temperature, salinity, dissolved oxygen (DO), chemical oxygen demand (COD), dissolved inorganic nitrogen (DIN), ammonium-nitrogen (NH4<sup style='margin-left:-7px;'>+-N), nitrate-nitrogen (NO3<sup style='margin-left:-7px;'>--N), nitrite-nitrogen (NO2<sup style='margin-left:-7px;'>--N), phosphate-phosphorus, (PO4<sup style='margin-left:-7px;'>3--P) and silica. PCA conveyed the amount of nutrients originating from the river, the organic pollution level, and seasonal changes. Subsequently, principal component scores were calculated for each point. It was concluded that the Ariake Sea environment has been affected by two main factors, which are the nutrients from the Chikugo River and anticlockwise tidal residual flow. These two factors must be considered for the environmental restoration of the Ariake Sea.展开更多
Rice grows well under certain condition and environment including soil, water and nutrients. Some researches have shown that traditional method with continues flooding need tremendeous amount of water for rice cultiva...Rice grows well under certain condition and environment including soil, water and nutrients. Some researches have shown that traditional method with continues flooding need tremendeous amount of water for rice cultivation and gives low water productivity. To increase the water productivity, number of water saving irigation techniques have been studied and applied. Study on effect of number of water irrigation treatments on water productivity of rice was carried out. Eight irrigation treatments were conducted for growing rice in pot experiment i.e. shallow intermittent irrigation (SII), alternate wetting and drying (AWD1, AWD2, AWD3 and AWD4), shallow water depth with wetting and drying (SWD1 and SWD2), and semi-dry cultivation (SDC). The performance of those treatments in terms of agronomic and water parameters was compared to the shallow intermittent irrigation as a control method. The study reveals that the shallow intermittent irrigation needs the highest amount of water compare with other treatments. The lowest amount of water was achieved under the semi-dry cultivation. It could save water up to 18.4% compare to the control treatment. By using the alternate wetting and drying and the shallow water depth with wetting and drying treatments, irrigated water can be reduced up to 13.1% and 5.4%, respectively. The highest grain was obtained by alternate wetting and drying (AWD4) and the semi-dry cultivation yielded the smalest grain. On average the alternate wetting and drying and shallow water depth with wetting and drying increased the grain yield by 22.9% and 17.9%, whereas the semi-dry cultivation reduced the yield up to 14% compare to the shallow water depth treatment. The alternate wetting and drying treatments have significantly improved the water productivity by 41.6%, shallow water depth with wetting and drying increased by 24.2% relative to the shallow intermittent irrigation treatment, whereas the most saving water treatment i.e. the semi-dry cultivation performed quite similar with the shallow water depth treatment, as a result of low grain yields under the treatment.展开更多
The removal of phosphorus from water using marble dust as sorbent material was studied by conducting batch tests, kinetic sorption model and isotherm model. The kinetic sorption model based on a pseudo equation was ap...The removal of phosphorus from water using marble dust as sorbent material was studied by conducting batch tests, kinetic sorption model and isotherm model. The kinetic sorption model based on a pseudo equation was applied to predict the rate constant of sorption. Thorough investigations to understand the mechanism of phosphorus sorption onto the marble dust using kinetic sorption models, pseudo first order and pseudo second order kinetic sorption models showed that the kinetic sorption is consistent with the second order model, from which it can be inferred that the mechanism of sorption is chemisorption. The Langmuir and Freundlich isotherm models were applied to describe the equilibrium isotherms. The results of isotherm models showed that the Langmuir isotherm agrees very well with the experimental data compare with Freundlich isotherm. Batch tests and kinetic sorption models results showed that using the marble dust as sorbent material could be remove more than 94.3% of phosphorus from water.展开更多
文摘The aim of this study is to investigate the condition of the Ariake Sea, Japan, which has been suffering from severe environmental issues for the past few decades. Water quality data have been generated from several points in this area for over 30 years by the Fukuoka, Saga, Kumamoto, and Nagasaki prefectures. In order to understand the characteristics of this sea, principal component analysis (PCA) was utilized using 11 water quality parameters;transparency, temperature, salinity, dissolved oxygen (DO), chemical oxygen demand (COD), dissolved inorganic nitrogen (DIN), ammonium-nitrogen (NH4<sup style='margin-left:-7px;'>+-N), nitrate-nitrogen (NO3<sup style='margin-left:-7px;'>--N), nitrite-nitrogen (NO2<sup style='margin-left:-7px;'>--N), phosphate-phosphorus, (PO4<sup style='margin-left:-7px;'>3--P) and silica. PCA conveyed the amount of nutrients originating from the river, the organic pollution level, and seasonal changes. Subsequently, principal component scores were calculated for each point. It was concluded that the Ariake Sea environment has been affected by two main factors, which are the nutrients from the Chikugo River and anticlockwise tidal residual flow. These two factors must be considered for the environmental restoration of the Ariake Sea.
文摘Rice grows well under certain condition and environment including soil, water and nutrients. Some researches have shown that traditional method with continues flooding need tremendeous amount of water for rice cultivation and gives low water productivity. To increase the water productivity, number of water saving irigation techniques have been studied and applied. Study on effect of number of water irrigation treatments on water productivity of rice was carried out. Eight irrigation treatments were conducted for growing rice in pot experiment i.e. shallow intermittent irrigation (SII), alternate wetting and drying (AWD1, AWD2, AWD3 and AWD4), shallow water depth with wetting and drying (SWD1 and SWD2), and semi-dry cultivation (SDC). The performance of those treatments in terms of agronomic and water parameters was compared to the shallow intermittent irrigation as a control method. The study reveals that the shallow intermittent irrigation needs the highest amount of water compare with other treatments. The lowest amount of water was achieved under the semi-dry cultivation. It could save water up to 18.4% compare to the control treatment. By using the alternate wetting and drying and the shallow water depth with wetting and drying treatments, irrigated water can be reduced up to 13.1% and 5.4%, respectively. The highest grain was obtained by alternate wetting and drying (AWD4) and the semi-dry cultivation yielded the smalest grain. On average the alternate wetting and drying and shallow water depth with wetting and drying increased the grain yield by 22.9% and 17.9%, whereas the semi-dry cultivation reduced the yield up to 14% compare to the shallow water depth treatment. The alternate wetting and drying treatments have significantly improved the water productivity by 41.6%, shallow water depth with wetting and drying increased by 24.2% relative to the shallow intermittent irrigation treatment, whereas the most saving water treatment i.e. the semi-dry cultivation performed quite similar with the shallow water depth treatment, as a result of low grain yields under the treatment.
文摘The removal of phosphorus from water using marble dust as sorbent material was studied by conducting batch tests, kinetic sorption model and isotherm model. The kinetic sorption model based on a pseudo equation was applied to predict the rate constant of sorption. Thorough investigations to understand the mechanism of phosphorus sorption onto the marble dust using kinetic sorption models, pseudo first order and pseudo second order kinetic sorption models showed that the kinetic sorption is consistent with the second order model, from which it can be inferred that the mechanism of sorption is chemisorption. The Langmuir and Freundlich isotherm models were applied to describe the equilibrium isotherms. The results of isotherm models showed that the Langmuir isotherm agrees very well with the experimental data compare with Freundlich isotherm. Batch tests and kinetic sorption models results showed that using the marble dust as sorbent material could be remove more than 94.3% of phosphorus from water.
