Vol 33 No 4 Text - International Ozone Association
Vol 33 No 4 Text - International Ozone Association
Vol 33 No 4 Text - International Ozone Association
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<strong>Ozone</strong> News <strong>Vol</strong>ume <strong>33</strong>, <strong>No</strong>. 4<br />
The reclamation system flow<br />
As shown in Figure 1, the developed reclamation system<br />
consists of a pre ozone process, bio filtration process,<br />
ozone oxidation process and MF membrane process. Pre<br />
ozone and bio filtration treat a part of organic matters<br />
and nitrogen in the secondary effluent and have a<br />
function to decrease ozone dosage in following ozone<br />
treatment. <strong>Ozone</strong> can decompose color and odor by<br />
oxidation function and disinfect bacteria. MF membrane<br />
is a hollow fiber with pore size of 0.1μm and can remove<br />
micro suspended matters including bacteria and<br />
Cryptosporidium.<br />
Features of MF membrane<br />
MF membrane is made from polyvinylidenefluoride that<br />
has a high ozone resistance. In addition, the membrane<br />
module is made from silicon that has an ozone resistance.<br />
Therefore, this membrane can filter the suspended water<br />
that includes dissolved ozone.<br />
Experimental Methods<br />
To clarify treatment efficacy and performance<br />
characteristics, pilot test was carried out during 5 months.<br />
The flow of test plant is shown in Figure 2. Treatment<br />
capacity was approximately 30 m 3/day. The treated water<br />
Figure 2. The experimental flow sheet of the reclamation system.<br />
Page 22<br />
sampled from each treatment process was analyzed<br />
regularly. The analyzed items were BOD, COD,<br />
heterotrophes, Escherichia coliform, fecal coliform,<br />
ammonia nitrogen, color and so on. In addition,<br />
Cryptosporidium was also examined to prove treatment<br />
efficacy.<br />
Regarding membrane operation, the behavior of the<br />
transmembrane pressure (TMP) was examined with<br />
change of dissolved ozone concentration on membrane<br />
surface. After deciding adequate dissolved ozone<br />
concentration for preventing the rise of TMP, the<br />
continuous filtration test was carried out with controlling<br />
dissolved ozone concentration automatically.<br />
Results and Discussion<br />
Treatment efficacy of this reclamation system<br />
The results of analyzed water quality are shown in Table<br />
I. Heterotrophes, escherichia coliform and fecal coliform<br />
are sterilized in the ozone treatment process. BOD is<br />
removed to 87%. Color is reduced to 8 (c.u.) on ozone<br />
treatment process and furthermore 1(c.u.) on membrane<br />
process. This is because ozone coagulates a part of color<br />
substances. Most of the ammonia nitrogen is nitrified by<br />
the bio filtration process and converted to nitrate<br />
nitrogen. The membrane process can remove not only
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