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The addition of electrostatic precipitator ash to forest industrial wastewater treatments increases the oxygen transfer rate and saves the energy needed for aeration
Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences.
2014 (English)In: Digital  Proceeding Of The  ICOEST’2014 - , SIDE, 2014Conference paper, Abstract (Refereed)
Abstract [en]

More than 30 m3 of water is needed for each metric tonne of paper. Most of the pulp and paper mills use an aerobic biological wastewater treatment. Aeration is the single most energy demanding process in the wastewater treatment plant; therefore it is desirable to control energy consumption when energy needs to be conserved. The aeration efficiency in pulp and paper industrial effluents is often low.  80 – 90% of added oxygen passes through the water volume and leaves with the off-gases. To increase the aeration efficiency, the process needs the oxygen transfer rate from the air bubble into the water to increase. The bubble size affects the oxygen transfer rate. In small bubbles, with a larger area/volume ratio the oxygen transfer rate is often fast and more efficient. The wastewater properties affect the bubble size. A decreased surface tension ensures smaller bubbles. The aim of this study was to show that a waste material, precipitator ash, could be used to decrease wastewater surface tension and thereby increase the oxygen transfer rate. The results from laboratory aeration trials show that the oxygen transfer rate coefficient (KLa) increases by 25% when small concentrations of electrostatic precipitator ash, from a flue gas treatment, were added to the process effluent.

Place, publisher, year, edition, pages
2014.
Keyword [en]
Oxygen transfer rate, Precipitator ash, Pulp and Paper, Surface tension, Wastewater
National Category
Engineering and Technology
Research subject
Environmental and Energy Systems
Identifiers
URN: urn:nbn:se:kau:diva-33757OAI: oai:DiVA.org:kau-33757DiVA: diva2:748469
Conference
2nd international conference on environmental science and technology – Side 14–17 may 2014 Side, Antalya Turkey
Projects
Salta bubblor
Available from: 2014-09-19 Created: 2014-09-19 Last updated: 2015-07-08Bibliographically approved

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