Electronic Journal of Polish Agricultural Universities (EJPAU) founded by all Polish Agriculture Universities presents original papers and review articles relevant to all aspects of agricultural sciences. It is target for persons working both in science and industry,regulatory agencies or teaching in agricultural sector. Covered by IFIS Publishing (Food Science and Technology Abstracts), ELSEVIER Science - Food Science and Technology Program, CAS USA (Chemical Abstracts), CABI Publishing UK and ALPSP (Association of Learned and Professional Society Publisher - full membership). Presented in the Master List of Thomson ISI.
2007
Volume 10
Issue 1
Topic:
Civil Engineering
ELECTRONIC
JOURNAL OF
POLISH
AGRICULTURAL
UNIVERSITIES
Siwiec T. 2007. THE SPHERICITY OF GRAINS OF FILTRATION BEDS APPLIED FOR WATER TREATMENT ON EXAMPLES OF SELECTED MINERALS, EJPAU 10(1), #30.
Available Online: http://www.ejpau.media.pl/volume10/issue1/abs-30.html

THE SPHERICITY OF GRAINS OF FILTRATION BEDS APPLIED FOR WATER TREATMENT ON EXAMPLES OF SELECTED MINERALS

Tadeusz Siwiec
Department of Civil Engineering and Geodesy, Water Supply and Sewage Systems Section, Warsaw Agricultural University, Poland

 

ABSTRACT



The paper describes several methods of determining the sphericity of bed grains and their verification in respect to selected minerals, such as: anthracite, barite, chalcedonite, diatomite, clinoptylolite, nevtraco, sand and pyrolusite. In order to make the results more reliable the tests were performed for 10 fractions of each bed. Since the above mentioned minerals, exploited in technical processes, are not uniform, it was necessary to apply intermediary methods, which enable to determine the averaged sphericity. The testing consisted in measuring other parameters which, together with sphericity, are components of suitable calculation formulas. Formulas of Ergun, Wen and Yu, Narshimhan, Dharmajah and Cleasby, as well as that by Cleasby and Fan, were applied.

It has been shown that reliable results may be obtained only by performing a quite long series of tests, because even small errors in measuring led to noticeable deviations from average values. Most reliable results were provided by formulas of Wen and Yu, as well as Narshimhan. The method of Dharmajah and Cleasby raises doubts, because sphericity obtained by this method gave results that increased with the growing velocity of rinsing, which should not happen, as sphericity is a constant value for a material.

Key words: sphericity, bakwashing rapid filters, filtration beds.


Tadeusz Siwiec
Department of Civil Engineering and Geodesy,
Water Supply and Sewage Systems Section,
Warsaw Agricultural University, Poland
Nowoursynowska St. 159, 02-776 Warsaw, Poland
Phone: +48 22 59 35 161
email: Tadeusz_Siwiec@sggw.pl

Responses to this article, comments are invited and should be submitted within three months of the publication of the article. If accepted for publication, they will be published in the chapter headed 'Discussions' and hyperlinked to the article.