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Results
The first trials of the new wastewater plant started in January 2005. These trials consisted of dry test of the machinery (pumps and other equipment).
The wet trials of the plant (testing pumps, pipes and other equipment) using water started in February 2005. During March 2005 the building up of an active biomass started (using activated sludge from municipal wastewater treatment plant as starting material).
Initial trials using actual wastewater started in April and on the 21 April 2005 the first water was discharged from the treatment plant to the river.
The wastewater treatment plant is now operating and running with wastewater from the tannery. The preliminary results so far are very positive and as an example can be mentioned that the nitrogen removal is working according to the expected goals.
The results of some key parameters from September 2005 - November 2006 are given in table below. It should be noted that the plant has been running during nearly one year and the performance of the plant has never been below 85%, despite the Scandinavian winter conditions.
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|
Incoming (mg/l) |
Outgoing (mg/l) |
Reduction |
|
BOD |
4686 |
81 |
98,3% |
|
COD |
10371 |
889 |
91,4% |
|
Nitrogen |
451 |
58 |
87,2% |
|
Chromium |
6,6 |
0,86 |
86,9% |
In August 2007, an additional precipitation step was added in order to further improve the efficiency of the plant. The following results were obtained for some key parameters during October-December 2007:
|
|
Incoming (mg/l) |
Outgoing (mg/l) |
Reduction |
|
BOD |
4 133 |
13 |
99,7% |
|
COD |
9 800 |
567 |
94,2% |
|
Nitrogen |
320 |
23 |
92,8% |
|
Chromium |
6,6 |
0,21 |
96,8% |
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