Volume 10
Issue 2
Environmental Development
JOURNAL OF
POLISH
AGRICULTURAL
UNIVERSITIES
Available Online: http://www.ejpau.media.pl/volume10/issue2/abs-16.html
THE INFLUENCE OF BACKWASHING METHODS ON THE INITIAL EFFLUENT QUALITY DURING DEIRONING OF WATER
Tadeusz Siwiec1, Joanna Troińska2
1 Department of Civil Engineering and Geodesy,
Water Supply and Sewage Systems Section,
Warsaw Agricultural University, Poland
2 Water Supply and Sewage Systems Works Ltd., Nowy Dwor Mazowiecki, Poland
ABSTRACT
The aim of research was to determine the minimal time of initial effluent discharge during backwashing with the use of raw and treated water, as well as with variable filtration velocity and different granules equivalent diameter of the bed. The following hypotheses were made: minimal time of initial effluent discharge is not constant and depends on granules equivalent diameter, filtration velocity and kind of water used for backwashing iron concentration distribution in initial effluent is the multinomial function of granules equivalent diameter and filtration velocity, initial values of above distribution significantly depend on water used for backwashing ( raw water, treated water) The investigations were performed on experimental installation on universities water supply plant. Measuring parameter was concentration of iron in raw water and treated water. The ranges of bed granulation variability were following: 0.64 – 0.80 mm; 1.00 – 1.25 mm; 1.60 – 2.00 mm. The ranges of filtration velocity were following: 11.5 m·h-1; 17.25 m·h-1; 23.0 m·h-1. The research was carried out in combinations of all the aforementioned parameters, each bed was backwashed with both raw and treated water and for each bed filtration was performed at all the aforementioned velocities. Approximate times of reaching the iron concentration of 0.2 mg·dm-3 for chosen cases are as follows: backwashing with treated water – [0.64 ÷ 0.80 mm] 11.5 m·h-1 It can be asserted that unequivocal schematic recommendations regarding the selection of the time at which the first portions of the effluent are to be discharged to sewage system require a more in-depth analysis and the assumed time of 10 minutes may frequently prove be too short.
0 min; 17.25 m·h-1 23 min; 23.0 m·h-1 32 min; [1.60 ÷ 2.00 mm] 11.5 m·h-1 49 min; 17.25 m·h-1 57 min; 23.0 m·h-1 58 min; backwashing with raw water – [0.64 ÷ 0.80 mm] 11.5 m·h-1 33 min; 17.25 m·h-1 35 min; 23.0 m·h-1 36 min; [1.60 ÷ 2.00 mm] 11.5 m·h-1 125 min; 17.25 m·h-1 152 min; 23.0 m·h-1 170 min;
Key words: filters, backwashing, quality of initial effluent.
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
Joanna Troińska
Water Supply and Sewage Systems Works Ltd., Nowy Dwor Mazowiecki, Poland
Gen. Berlinga 100, Nowy Dwor Mazowiecki, Poland
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.