Iwa publishing jun 2003 (3 Ergebnisse)
- Softcover
Anbieter: AHA-BUCH GmbH, Einbeck, DeutschlandAHA-BUCH GmbH
Verkäufer/-in kontaktierenVerkäufer/-in mit 5 SternenZustand: Neu
EUR 183,42
EUR 61,20 VersandVersand von Deutschland nach USAAnzahl: 2 verfügbar
Taschenbuch. Zustand: Neu. Neuware - Biological denitrification by heterotrophic bacteria is common in the wastewater industry in the U.S. and in drinking water processing in Europe. To facilitate heterotrophic denitrification, organic compounds such as methanol, ethanol and acetic acid are added to provide a carbon source for t…he bacteria. The resulting organic carbon residual may create problems with chlorination. The addition of these carbon compounds is expensive and results in added sludge production. This study focused on the use of autotrophic hydrogen oxidizing bacteria for denitrification. The method transfers hydrogen gas to solution via microporous hollow fiber membranes. Typically, gases are supplied to a system using conventional bubble diffusers. The conventional bubble aeration system has a low gas transfer efficiency, and, as a result, the cost of dissolving the required amount of gas is very high. In this study, microporous hollow fiber membranes were employed to supply hydrogen gas to hydrogen oxidizing autotrophic bacteria. Laboratory scale membrane modules were constructed and mass transfer studies were carried out to develop the design correlations for hydrogen gas transfer. A mixed culture was obtained and acclimated for batch denitrification studies. Both Sodium carbonate and carbon dioxide were used to deliver inorganic carbon. Bench scale continuous flow biofilm reactors containing plastic media were operated to remove nitrate from water. The required hydrogen gas was supplied at a constant rate via gas transfer modules, containing sealed end microporous hollow fiber membranes. The reactors were optimized for removal of nitrate and nitrite by varying the recycle ratios and hydraulic detention time. Experimental results indicated the presence of hydrogen oxidizing denitrifiers in wastewater sludge. Adequate pH control was possible and the pH averaged around 6.95. Gas transfer studies indicated that hydrogen transfer was primarily controlled by liquid film diffusion. Hydrogen gas was successfully delivered to the reactor via the hollow fiber membrane gas transfer module. Nitrate and hydrogen concentration measurements indicated that the system did not experience hydrogen limitations at detention times of 3.25 hours or greater. The use of hollow fiber membrane module appears to be a viable technology for transferring hydrogen gas to water. The research results in this report provide valuable information for pilot and full-scale studies for the water/wastewater community focusing on membrane processes for autotrophic denitrification.
- Softcover
Anbieter: AHA-BUCH GmbH, Einbeck, DeutschlandAHA-BUCH GmbH
Verkäufer/-in kontaktierenVerkäufer/-in mit 5 SternenZustand: Neu
EUR 183,42
EUR 62,27 VersandVersand von Deutschland nach USAAnzahl: 2 verfügbar
Taschenbuch. Zustand: Neu. Neuware - The purpose of this research project was to examine construction projects that successfully reduced RDII. The research began with a literature review of all published records describing RDII removal projects. Initially, the review identified many projects; however, subsequent evaluation of av…ailable information revealed several important realities. First, most RDII removal projects in the country go undocumented. Second, of the RDII removal project summaries that have been published, few provide good data. Third, data gathering and analyses for this report were hampered by lack of documentation, lost or unavailable monitoring data, and weaknesses in monitoring techniques. Projects with sufficient information describing the conditions before the RDII removal project received a detailed analysis. In all, the case studies from the six agencies presented in this report (1) document before-and-after RDII levels, (2) quantify the RDII reduction achieved, and (3) describe the cost-effectiveness of the removal. As more than one project was documented for some agencies, a total of 12 RDII projects received review. The projects examined include both those that 'successfully' reduced RDII and those that did not. In general, the conclusion was that utilities run the risk of not removing significant RDII unless they address private sewer laterals. The only cases examined where significant RDII was removed were those that addressed private sewers or inflow sources.
- Softcover
Anbieter: AHA-BUCH GmbH, Einbeck, DeutschlandAHA-BUCH GmbH
Verkäufer/-in kontaktierenVerkäufer/-in mit 5 SternenZustand: Neu
EUR 183,42
EUR 62,37 VersandVersand von Deutschland nach USAAnzahl: 2 verfügbar
Taschenbuch. Zustand: Neu. Neuware - Rapid growth of cities and industries in China is having a dramatic impact on the environment. To counteract further decrease of water quality of rivers, lakes and groundwater bodies, an ambitious environmental remediation programme needs to be designed and brought into action. Intensive rese…arch and development activity are required to provide tailored solutions. The articles compiled in the book describe the current situation in China with respect to surface water quality and wastewater treatment, and provide results of specific research projects, leading the way to a China-specific up-to-date water treatment technology. Discussed are lessons to be learnt from the experience made in other countries, particularly with respect to regulations and management practices.
