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| | Fast Work in Poland. New sewage treatment plants in record time. |
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As Poland addresses its environment clean-up problems, the government predicts it will be needing a huge, ongoing investment in building new sewage treatment plants. And in Ulanow, in south eastern Poland, ITT Flygt implemented the system technique and supplied pumping, mixing and aeration equipment for such a plant with a capacity for 3,000 people - a plant that was completed in just four short months after the start of construction.
Following the success of the Ulanow plant, ITT Flygt has been requested to provide the technique in a number of similar plants in other parts of the country during the near future. This is done in cooperation with international and local contractors.
The opening of the new sewage plant in Ulanow was witnessed by hundreds of interested townspeople, many of whom were young. The new plant is seen as a step in a new direction for Ulanow, and for Poland as a whole, a country that is becoming more and more concerned about its environment.
Traditionally, many of Ulanow's inhabitants made their living from the San river - the very river the new treatment plant will be helping to clean up. The river, a tributary to the Vistula, was used to deliver goods from the Polish hinterlands to the coastal city of Gdansk.
95% cleaning efficiency
Comprising mechanical, biological and chemical treatment in three stages, the technology employed in Ulanow is reliable and well proven. ITT Flygt's Warsaw branch put considerable effort into the engineering of the plant to adapt the technology to two important requirements - fast results and the lowest possible cost with regard to operational reliability and cleaning efficiency.
The answer was a 'building block' solution that is easy to operate and gives maximum flexibility, according to Robert Rybatski, project manager at ITT Flygt Poland.
The sewage treatment plant is constructed of special concrete building units that were prefabricated. The units can be easily combined to build basins of suitable size. The same construction technique is being used at the sewage treatment plants which are built in other areas. A number of these facilities are several times larger than the Ulanow works.
The cleaning efficiency of the Ulanow plant cannot be measured until the biological bacteria build up, which usually takes a few months of operation. Based on preliminary laboratory tests, however, a cleaning efficiency of 95 percent is expected. Nitrogen is being reduced by 70 percent and phosphorus by 67 percent.
Biological and chemical cleaning in batches
The Ulanow plant treats about 600 cubic meters of sewage per day. Of this, 75 percent comes from the local sewage network and the remainder is trucked in from the neighboring community of Bielawy. After screening to remove large solid particles, the sewage is deposited in a retaining basin where return sludge is added and mixed in.
About 150 cubic meters of sludge is emptied from the basin every six hours and fed into two parallel cleaning systems consisting of biological and chemical treatment basins.
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A. Raw sewage
B. Coarse screening
C. Retaining basin
D.Automatic control station
E. Fe2(SO4)3
F. Sludge
G. Pump
H. Mixer
I. Ejector aerator
J. Biological basins
K. Chemical basins
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The system features a four-stage biological treatment. During mixing, denitrification occurs during the first 90 minutes of the 12 hour cycle. This is followed by seven hours of intensive mixing and aeration with Flygt Flo-Gets.
The second stage, sedimentation, takes two and a half hours after which suspended solids settle on the bottom leaving a 1.5 meter layer of clear sewage which can be pumped to the chemical basin.
"Any remaining sludge is trucked to the nearby city of Rudnik"
While the liquid is being pumped over to the chemical basin, iron sulfate is added, and after mixing, the flock settles at the bottom during a second sedimentation process lasting nearly ten hours. The clear effluent is then dewatered and discharged into the San river by an automatically controlled draining valve. Sludge pumps in the biological and chemical basins pump equal quantities of sludge to the sludge thickener, and also return sludge to the retaining basin for mixing with raw sewage. The sludge is then trucked to the nearby city of Rudnik for final treatment.
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Where there´s a will, there´s a way
As part of the opening ceremony, the Mayor of Ulanow requested the firing of the ceremonial 300-year-old cannon last used to signal armistice at the end of the First World War.
Poland is taking its environmental problems seriously, recognizing that they affect not only their own population, but also their neighbors, particularly those around the Baltic. The success of the project to date, and the speed with which it has been completed, is an encouragement for further steps to improve municipal sewage handling in Poland, and elsewhere.
Technical data
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| Biological cleaning, 2 times/day |
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| Denitrification/mixing 1,5 hr |
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| Aeration 7,0 hr |
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| Sedimentation 2,5 hr |
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| Pumping, clarification 1,0 hr |
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| Chemical cleaning |
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| Sedimentation with Fe2(SO4)3 |
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| Sedimentation |
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| Dewatering |
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| pump sump 10 m deep |
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| 2 CP 3127 LT |
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| Retaining basin |
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| 2 SR 4400 |
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| 1 CP 3102 LT |
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| Biological basin |
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| 2 Flo-Get FG212-59 |
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| 2 SR 4352 mixers |
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| 1 CP 3067 sludge pump |
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| 1 LL 3085 dewatering pump |
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| Chemical basin |
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| 1 SR 4352 mixer |
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| 1 CP 3067 sludge pump |
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