Nowadays, it is matter of course, that we use water for everything: washing dishes, laundering clothes, in industry, drinking regime... After we used the water, we do not care anymore where the water flows away then. But I was so interested in it, so I was looking for some informations, what technologies are being used in Sewage Treatment Plant in Holíč, so the purified water can be discharged into the water stream, but by its composition it cannot disturb the ecological balance in the watercourse. #scichallenge2017 #environment

2. Sewage
treatment plant
in Holíč (Slovakia)
was built in 1975
and completely
reconstructed in
2013
It includes
biological and
mechanical
process

3. Water flowing into sewage
treatment plant is being
cleaned by removing the dirt
by the rakes
 Dirt is directed into containers
then
In our sewage treatment plant
were found things like clothing,
tree tribe or dead young deer
during this process!

4. -Water is being divided into
two 6mm or 3mm rakes
(dirt removers)
-The rakes are set for some
period of time and they're
making “moves”
-It is a good thing, because
water is washing the dirt
caught on the rakes and
then there are organic
substances released during
this process which are
useful

6. Dirt is washed in
whirlpool sand separator,
it is a simple process
Water used during this
process is then directed
into the sewage
treatment plant process

7. Then, there's a
partitioning object,
which is being
opened in cause of
crash to make the
biological part closed
This is a drain, which
is being used in case
of rainwater
Then, the water
flows away and
directs into the tanks

8. There's a settlement tank,
where primary sludge is
produced
 Primary sludge is the
biggest producer of biogas
There's a water flowing
here for some period of
time, where the sludge
will go down to the
bottom
 Unnecessary sludge is
removed

9. Sludge is
collected in
here

10. Sludge water is
drained back to the
process, it's
translucent
Even though the
water is clear, it is
highly
concentrated, so it
must go back to the
process again

11. Then, water flows out of
the settlement tank into
the partitioning object
Sludge foam is a thing
which is being made on
the surface
Sometimes, the sludge
foam is done because of
wrong processing, e.g.
there's a more nitrogen or
ammonia in the water
Color of the sludge foam
is important
If the foam is creamy
brown, the sludge is
younger
If the foam is dark brown,
the sludge is older

12. Mechanical
process is done
and now the
water is
starting to be
cleaned by
biological
process

13. A lot of children have seen: Yaaay, bubbles! I'd love to swim in
here!” but they're wrong. It is impossible to swim in here, because
the water density is low
There's a nitrification process going on in the tanks with help of
nitrifying microorganisms

14. In this cylinder is a collection of regeneration and activation tanks
After 30 minutes the sludge will go down to the bottom
Sludge sedimentation is determined by technologist
If the sedimentation is high, excess sludge will be drained from the
sludge in the regeneration tanks

15. Sewage water
continues in
cleaning
treatment
The water flows
into Morava river
after mechanical
process

17. I planted a plant called
Echinodorus major
I was experimenting
with them with sewage
treatment plant water
The first bottle was
water from supply to the
sewage treatment plant
The second one was
drain water from the
sewage treatment plant

18. After 24
hours
After 48
hours
After 72
hours
After 96
hours
After 120
hours

19. Special thanks goes to: Mrs. Silvia Kováčiková,
head of WWTP in Holíč, BVS, a.s.