Alexander Szabo and Oscar Engle - Svenskt Vatten

stirred up. The algae population may not have developed entirely after the de-sludging, and since
algae contribute to the effluent TSS values, it could be another possible explanation.
For the composite value analyzed on the 9-10 January, between 00-04, it can be seen that it is
significantly lower than the other values from this date (Figure 8.4). One possible reason could be
that a pump station is located just after the outlet where the effluent samples were taken. The
pumps are working discontinuously and start when the water reaches a specific height in the
treatment pond. When the pumps start operating, the effluent water flow increases drastically.
This causes differences in the water quality and the measured changes of effluent quality over
time may therefore have been influenced by the unknown pumping pattern.
Figure 8.3: Total Suspended Solids (TSS) in the effluent on the 5-6 November 2009.
Figure 8.4: Total Suspended Solids (TSS) in the effluent on the 9-10 January 2010.
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