Bioleaching Xiangjiang River alkaline sediment contaminated by multiple heavy metals was investigated. Multiple metals in alkaline sediment possess significant toxicity to aquatic organisms or humans and will greatly ...Bioleaching Xiangjiang River alkaline sediment contaminated by multiple heavy metals was investigated. Multiple metals in alkaline sediment possess significant toxicity to aquatic organisms or humans and will greatly inhibit bioleaching. The bioleaching method using autotrophic bacteria mixed with heterotrophic bacteria can solve this problem successfully. The experiment results showed that bioleaching efficiencies of Zn, Mn, Cu, and Cd were 95.2 %, 94.2 %, 90.1 %, and 84.4 %, respectively. Moreover, the changes of heavy metal concentrations in different fractions in contaminated sediment before and after bioleaching were analyzed by selective sequential extraction, and it was discovered that the main fractions of Zn, Mn, Cu and Cd after bioleaching are Fe-Mn oxide, organic associated form and a residual form. Its biotoxicity decreased greatly. The bioleaching heavy metals from sediment using autotrophic bacteria combined with heterotrophic bacteria can effectively improve the bioleaching efficiency and reduce toxicity.展开更多
The present study is concerned with the lifting of seabed materials by a BJT （bubble-jet-type） air-lift pump patented by Sadatomi. The targets are methane-hydrate rich muds on the bed about 200 m in depth around Jap...The present study is concerned with the lifting of seabed materials by a BJT （bubble-jet-type） air-lift pump patented by Sadatomi. The targets are methane-hydrate rich muds on the bed about 200 m in depth around Japan islands and rare-earth rich muds on the bed deeper than 4,000 m around Minami-Torishima islands in the Pacific Ocean. Feasibility studies were conducted using 50 mm I. D. （inner diameter） and 5.0 m long vertical pipe as the pump upriser, VC （vinyl chloride） particles and natural sands mixture in the methane-hydrate case, and ceramics particles with 3,761 kg/m^3 in density in the rare-earth case as the deposits. From the methane-hydrate simulation experiments, an efficient operation condition with high VC particles to sands lifting ratio has been clarified. In the rare-earth case, the air supplies from two different midways in the upriser pipe have been tested together with the bottom supply because the air supply from the upriser bottom is very hard in deep sea. The effects of the air supply position on the pump performance have been clarified by the experiments and the simulations with a revised model applicable to the midway air supply type.展开更多
The research dealt with assessment of logistics service providers＇ capabilities in SECs （supporting subsea engineering companies） on the Tweneboa, Enyenra and Ntomme （TEN） project in Ghana. SECs need logistics se...The research dealt with assessment of logistics service providers＇ capabilities in SECs （supporting subsea engineering companies） on the Tweneboa, Enyenra and Ntomme （TEN） project in Ghana. SECs need logistics service providers who offer consolidated services for project optimization and fulfillment of local content requirements of the project. Relevant Staffof7 SECs and 10 logistics service providers in Ghana formed part of the target group. The weighted scoring model was used in selecting a logistics service provider based on certain criteria. The selection criteria included Quality, Health, Safety and Environmental （QHSE） policies [Q], Compliance to regulations （GRA, Work permit, petroleum regulation） [C], Delivery of goods on time and response rate to deliver [D], Vessel, Cargo attendance and transportation （sea freight and air freight） [V], and Logistics （Personal logistics and Logistics base facilities） [L]. The study concluded Consolidated Shipping Agency （Conship） was the best Logistics Service Provider to offer the best consolidated services for project optimization under the TEN project.展开更多
基金Projects(51174239,30700008)supported by the National Natural Science Foundation of ChinaProjects(20090461028,201003526)supported by China Postdoctoral Science Foundation
文摘Bioleaching Xiangjiang River alkaline sediment contaminated by multiple heavy metals was investigated. Multiple metals in alkaline sediment possess significant toxicity to aquatic organisms or humans and will greatly inhibit bioleaching. The bioleaching method using autotrophic bacteria mixed with heterotrophic bacteria can solve this problem successfully. The experiment results showed that bioleaching efficiencies of Zn, Mn, Cu, and Cd were 95.2 %, 94.2 %, 90.1 %, and 84.4 %, respectively. Moreover, the changes of heavy metal concentrations in different fractions in contaminated sediment before and after bioleaching were analyzed by selective sequential extraction, and it was discovered that the main fractions of Zn, Mn, Cu and Cd after bioleaching are Fe-Mn oxide, organic associated form and a residual form. Its biotoxicity decreased greatly. The bioleaching heavy metals from sediment using autotrophic bacteria combined with heterotrophic bacteria can effectively improve the bioleaching efficiency and reduce toxicity.
文摘The present study is concerned with the lifting of seabed materials by a BJT （bubble-jet-type） air-lift pump patented by Sadatomi. The targets are methane-hydrate rich muds on the bed about 200 m in depth around Japan islands and rare-earth rich muds on the bed deeper than 4,000 m around Minami-Torishima islands in the Pacific Ocean. Feasibility studies were conducted using 50 mm I. D. （inner diameter） and 5.0 m long vertical pipe as the pump upriser, VC （vinyl chloride） particles and natural sands mixture in the methane-hydrate case, and ceramics particles with 3,761 kg/m^3 in density in the rare-earth case as the deposits. From the methane-hydrate simulation experiments, an efficient operation condition with high VC particles to sands lifting ratio has been clarified. In the rare-earth case, the air supplies from two different midways in the upriser pipe have been tested together with the bottom supply because the air supply from the upriser bottom is very hard in deep sea. The effects of the air supply position on the pump performance have been clarified by the experiments and the simulations with a revised model applicable to the midway air supply type.
文摘The research dealt with assessment of logistics service providers＇ capabilities in SECs （supporting subsea engineering companies） on the Tweneboa, Enyenra and Ntomme （TEN） project in Ghana. SECs need logistics service providers who offer consolidated services for project optimization and fulfillment of local content requirements of the project. Relevant Staffof7 SECs and 10 logistics service providers in Ghana formed part of the target group. The weighted scoring model was used in selecting a logistics service provider based on certain criteria. The selection criteria included Quality, Health, Safety and Environmental （QHSE） policies [Q], Compliance to regulations （GRA, Work permit, petroleum regulation） [C], Delivery of goods on time and response rate to deliver [D], Vessel, Cargo attendance and transportation （sea freight and air freight） [V], and Logistics （Personal logistics and Logistics base facilities） [L]. The study concluded Consolidated Shipping Agency （Conship） was the best Logistics Service Provider to offer the best consolidated services for project optimization under the TEN project.
