Alexander Szabo and Oscar Engle - Svenskt Vatten

Figure 6.1: Map over the UTM campus area with (1) The WSP studied in this report (2) another
WSP within UTM; (3) biological-mechanical treatment plant; (Another campus area and treatment
plant is located in the north-east, outside the map) (Szabo & Engle, 2010)
The treatment system that this report will focus on consists of two parallel lines of facultative
ponds followed by maturation ponds (Figure 6.2). The available documents do not tell for how
many persons the ponds are dimensioned for, but according to the contractor for de-sludging
operation, this pond system was built to serve approximately a P.E. of around 8 000. The pond
system is a simple construction, where the influent waste water is divided in a chamber before it
enters each treatment line through pipes located under the water surface. The ponds have no
screening and objects of many different sizes have been seen floating in the pond. These objects
have a tendency to clog the cannels between the ponds. Since the water level of the receiving
river is higher than the effluent level, a pumping station is located between the pond and the river.
The pumps are currently working discontinuously, and during the time when the pumps are not
pumping, the ponds accumulate waste water beyond the designed water levels. The technical data
of the pond system can be found in Appendix G.
Figure 6.2: Shape of pond system with facultative ponds (1) followed by maturation ponds (2)
(Szabo & Engle, 2010).
6.3 Recipient
Introduction
The effluent from the WSP is released into a stream passing through the UTM area (Figure 6.3).
The stream transforms into two small lakes a few hundred meters downstream, where the main
entrance to UTM is located (see Figure 6.4). In these small lakes, canoeing activities take place
which demands good water quality. The part of water that origin from the WSP is large compared
to the upstream river water. Most of the water in the lakes is therefore considered mainly to be
effluent water from the WSP.
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