检索结果-南通市图书馆

Nitrate removal and extracellular polymeric substances of autohydrogenotrophic bacteria under various pH and hydrogen flow rates

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2018年第1期30卷 50-57页

作者： Tran-Ngoc-Phu Nguyen Pei-Chung Chen chihpin huang Institute of Enuironmental Engineering National Chiao Tung UniuersityHsinchu 300Chinese Taipei

In recent years there has been an increasing interest in the use of autohydrogenotrophic bacteria to treat nitrate from wastewater. However, our knowledge about the characteristics of extracellular polymeric substances（EPS） releasing by these activities is not yet very advanced. This study aimed to investigate the change in EPS compositions under various p H values and hydrogen flow rates, taking into consideration nitrogen removal. Results showed that p H 7.5 and a hydrogen flow rate of 90 m L/min were the optimal operating conditions, resulting in 100% nitrogen removal after 6 hr of operation. Soluble and bound polysaccharides decreased, while bound proteins increased with increasing p H. Polysaccharides increased with increasing hydrogen flow rate. No significant change of bound proteins was observed at various hydrogen flow rates.

关键词： Autohydrogenotrophic bacteria Nitrate removal Extracellular polymeric substances Polysaccharides Proteins

Hydrolyzed Al(Ⅲ) clusters:Speciation stability of nano-Al_(13)

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2011年第5期23卷 705-710页

作者： Shuifeng Wang chihpin huang Christopher W K. Chow Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China. E-mail: wgds@*** Institute of Environmental Engineering National Chiao Tung University Hsinchu Taiwan China Australian Water Quality Centre SA Water Corporation 250 Victoria Square Adelaide SA 5000 South Australia

Pure nano-All3 and aggregates at various concentrations were prepared to examine the particle size effect of coagulation with inorganic polymer flocculant. The property and stability of various species formed were characterized using Infrared, 27Al-NMR, photo correlation spectroscopy （PCS）, and Ferron assay. Results showed that concentration and temperature exhibited different roles on the stability of Al13. The quantity of Alb species analyzed by ferron assay in the initial aging period corresponded well with that of Al13, which has been confirmed in a dimension range of 1-2 nm by PCS. Al13 solutions at high concentrations （0.5-2.11 tool/L） were observed to undergo further aggregation with aging. The aggregates with a wide particle size distribution would contribute to the disappeared/decreased Al13 basis on the eTA1-NMR spectrum, whereas a part of Al13 would still remain as Alb. At low concentrations, All3 solution was quite stable at normal temperature, but lost its stability quickly when heating to 90~C.

关键词： nano-All3 clusters inorganic polymer flocculant speciation stability

Algal removal from cyanobacteria-rich waters by preoxidation-assisted coagulation-flotation: Effect of algogenic organic matter release on algal removal and trihalomethane formation

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2018年第1期30卷 147-155页

作者： Jr-Lin Lin Lap-Cuong Hua Shih Kai Hung chihpin huang Department of Environmental Engineering Chung Yuan Christian University Institute of Environmental Engineering National Chiao Tung University

The cyanobacteria-bloom in raw waters frequently causes an unpredictable chemical dosing of preoxidation and coagulation for an effective removal of algal cells in water treatment plants. This study investigated the effects of preoxidation with NaOCl and ClO_2 on the coagulation-flotation effectiveness in the removal of two commonly blooming cyanobacteria species, Microcystis aeruginosa（MA） and Cylindrospermopsis raciborskii（CR）, and their corresponding trihalomethane（THM） formation potential. The results showed that dual dosing with NaOCl plus ClO_2 was more effective in enhancing the deformation of cyanobacterial cells compared to single dosing with Na OCl, especially for CR-rich *** preoxidation approaches for CR-rich water effectively reduced the CR cell count with less remained dissolved organic carbon（DOC）, which benefited subsequent coagulation–flotation. However, preoxidation led to an adverse release of algogenic organic matter（AOM） in the case of MA-rich water. The release of AOM resulted in a poor removal in MA cells and a large amount of THM formation after oxidation-assisted coagulation-flotation process. The reduction in THM formation potential of CR-rich waters is responsible for effective algae and DOC removal by alum coagulation. It is concluded that the species-specific characteristic of cyanobacteria and their AOM released during chlorination significantly influences the performance of coagulation–flotation for AOM removal and corresponding THM formation.

关键词： Algogenic organic matter Preoxidation Coagulation-flotation Disinfection-by-products

Effects of C/N ratio on nitrate removal and floc morphology of autohydrogenotrophic bacteria in a nitrate-containing wastewater treatment process

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2018年第7期30卷 52-60页

作者： Tran Ngoc Phu Nguyen Shu-Ju Chao Pei-Chung Chen chihpin huang Institute of EnvironmentaZ Engineering National Chiao Tung University Hsinchu 300 Chinese Taipei

The effects of C/N ratio of a nitrate-containing wastewater on nitrate removal performed by autohydrogenotrophic bacteria as well as on the morphological parameters of floc such as floc morphology, floc number distribution, mean particle size（MPS）, aspect ratio and transparency were examined in this study. The results showed that the nitrate reduction rate increased with increasing C/N ratio from 0.5 to 10 and that the nitrogen removal of up to 95% was found at the C/N ratios of higher than 5（between 0.5–10）. Besides, high C/N ratio values reflected a corresponding high nitrite accumulation after 12-hr operation, and a fast decreasing rate of nitrite in the rest of operational time. The final p H values increased with the C/N ratio increasing from 0.5 to 2.5, but decreased with the C/N ratio increasing from2.5 to 10. There were no significant changes in floc morphology with the MPSs ranging from35 to 40 μm. Small and medium-sized flocs were dominant in the sludge suspension, and the number of flocs increased with the increasing C/N ratios. Furthermore, the highest apparent frequency of 10% was observed at aspect ratios of 0.5 and 0.6, while the transparency of flocs changed from 0.1 to 0.7.

关键词： Autohydrogenotrophic bacteria C/N ratio Floc morphology Nitrate reduction Nitrite accumulation Nitrogen removal