Ülemiste

1. LAKE ÜLEMISTE
macroflora & water treatment
Karena Kiis
TÖ-51

2. Lake Ülemiste
 Largest of the lakes surrounding Tallinn
 Main part of the Tallinn water supply system
 The Tallinn Water Company, AS Tallinna Vesi, has a treatment
plant on the North shore of the lake which supplies 90% of the
water to the city
 Other 10% from ground water wells
 On 18 March 2010 a DHL Antonov An-26 aircraft made an
emergency landing on the ice of Lake Ülemiste and 1,5 tons of
fuel leaked into the water

3. Lake Ülemiste
Max. length 4.1 km
Max. width 3.2 km
Surface area 9.436 km2
Average depth 2.5 m
Max. depth 4.2 m
Shore length 15.219 km
Surface elevation 35.7 m

6. Macroflora of lake Ülemiste in 2000
 Macrophyte vegetation covered 5.4% of the lake, 6% in 2004
 The mean width of the zone of macrophytes was 48.4 m and
the mean depth 1.4 m.
 Widest belt was in south-west part of the lake – 286 m
 The list of the macrophytes found over the entire lake contains
41 species of vascular plants, 1 moss species, and 5 species of
macroalgae.

7. Emergent macrophytes
Common reed /
pilliroog
Common club-rush /
järvkaisel
Common rivergrass /
rooghein

8. Floating-leaved macrophyte
Water knotweed / vesi-kirburohi

9. Shining pondweed /
läik-penikeel
Clasping-leaf
pondweed/
kaelus-penikeel
Sago pondweed /
kamm-penikeel
Grassy
pondweed /
hein-penikeel

10. Species Number of findings Frequency, % Depth limits, m
Common reed /
pilliroog
133 57.3 0.2-2.5
Common club-rush /
järvkaisel
97 41.8 0.2-1.9
Water knotweed /
vesi-kirburohi
62 26.7 0.3-2.0
Common rivergrass /
rooghein
36 15.5 0.2-2.0
Shining pondweed /
läik-penikeel
35 15.1 0.5-2.5
Clasping-leaf
pondweed/
kaelus-penikeel
25 10.8 0.7-1.3
Sago pondweed /
kamm-penikeel
8 3.4 0.5-1.5
Grassy pondweed /
hein-penikeel
7 3.0 0.4-1.4

11. Affective environmental factors
 Water-level fluctuations throughout 4 periods
 8 dry periods during 20th century
 CaHCO3 on the leaves of submerged macrophytes
 Renovations on shorelines
 Fish like bream
 NB! Submerged macrophytes are a very important structural
element in lakes and may markedly affect environmental
conditions of a lake by their ability to stabilize the clear-water
state.

12. ÜlemisteWater Treatment Plant
 .. has been treating water since 1927
 .. produces an average of 60,000 m3 of water per day
 Average water consumption in 2013 was 93 litres per inhabitant
 .. treats water by a treatment scheme often used world-wide
 Ozone is used in the treatment process to improve the quality, odour,
colour and taste
 Small amounts of chlorine is added in the drinking water, which is
effective protecton against bacteria as it travels through the network
 Ülemiste WTP constantly develop new technologies and proceed to
improve our water drinking experience

13. Water treatment process
 Surface water is gathered to Lake Ülemiste and directed to Water Treatment
Plant.
 Raw water passes through screens and microfilters, which remove algae and
plankton from the water.
 Water is led into reservoirs, where a mixture of ozone in air is injected into
the water to oxidize organic substances.
 A water treatment chemical coagulant is added to clarify the water.
 During the clarification phase particulate matter, chemical flocks and
precipitates are removed from the water.
 Water passes through filters. In summer, dependent on the quality of raw
water coming into the plant, activated carbon may be added in order to
remove any remaining particles and to improve the taste of the drinking
water.
 Chlorine is added to the water for disinfection purposes.
 The water is directed to drinking water reservoirs, from which it is pumped
to the city water network in accordance with demand.

14. Drinking water quality
 Drinking water quality is required to comply with “Quality and Control
Requirements and Analysis Methods for Drinking Water”
 The water quality is monitored following the Drinking Water Quality
Monitoring Programme approved by the Health Board.
 Drinking tap water is a growing trend
 Raw water quality indicators are analysed once a day at the intake to the
treatment system

15. Drinking water quality

16. Thank Your for listening!