6.1 Operation
After commissioning of the plant, an active activated slud-
ge layer with microorganisms forms in the aeration chamber
after 3-6 months. It is not necessary to feed any microorga-
nisms to this plant. We however consider a feeding of ac-
tivated sludge from the nearest sewage treatment plant rea-
sonable. Important: Only feed activated sludge into the ae-
ration chamber!
To ensure a smooth operation, maintenance intervals have
to be strictly adhered to. The timely emptying of the preli-
minary sedimentation chamber must be ensured.
The operation of the small sewage treatment plant is fully
automatic. In detail, there are three phases, the "normal",
"economy" and "holiday" phase. These differ with regard to
their aeration time and quantity. The actual purification takes
place during the normal phase (6 hours).
In case of an inadequate feeding of the plant (insufficient se-
wage inflow), it will automatically switch to the "economy
phase" (2 hours). In this phase, the aeration time is reduced
to the lower sewage quantity, to prevent "starving out" the
adapted microorganisms. If the plant remains in the "eco-
nomy phase" for a longer period of time (8 hours), it auto-
matically switches to the "holiday phase".
The "holiday phase" is characterised by an even lower sup-
ply of oxygen. Supplementary to that, a defined amount of
sludge is conveyed from the aeration chamber into the preli-
minary sedimentation at the end of the holiday phase. This
makes it possible to supply a certain amount of nutrients to
the aeration phase during the next feeding. This contributes
towards the preservation of the biology during a prolonged
standstill.
As soon as a sufficient amount of water is available in the
preliminary sedimentation chamber so that the floater is
switched on during the subsequent feeding, the plant will
automatically switch back to the normal phase.
This adaptation to different sewage quantities is automati-
cally controlled by the control unit. The corresponding phase
is indicated on the control unit. A general overview of the
pertinent phases and cycles is provided in chapter 2.5.
Heeding the following recommendations will help you avoid
unnecessary costs of repair and increase your plant's servi-
ce life:
• The plant must remain switched on all the time, even if you
are away on holiday.
• External water, such as rain, ground, swimming pool or fish
tank water may not be discharged into the plant.
• In the case of household detergents please pay attention
that these do not exhibit any acidic or alkaline reactions.
We recommend the use of biodegradable detergents and
washing agents.
• It must be possible to open the plant's covers.
• Ensure that the plant is regularly serviced by a specialised
firm.
6. Operation and disposal
• It is only necessary to have the preliminary sedimentation
desludged regularly (approx. every 12-24 months) by a
waste disposal contractor! After consultation with the re-
sponsible water authorities and conclusion of a mainten-
ance contract, this can however possibly also take place
in line with demand.
Note: If the plant is taken out of operation, it must be en-
sured that it continues to remain filled.
It is imperative to note the following:
You can continue to use any detergent and washing
agent, but please adhere to the manufacturers' dosing in-
structions!
It is also possible to use various drain cleaners, provided
the dosing according to manufacturers' specifications is
adhered to.
However, every time these detergents are discharged into
the plant, a number of bacteria die off. If possible, plea-
se make use of biodegradable detergents and dispense
with the use of drain cleaners (see 6.3).
6.2 Self-inspection by the operator
As operator of the sewage treatment plant it is your obliga-
tion vis-à-vis the water authority to ensure a smooth opera-
tion of the plant. Malfunctions on small biological sewage
treatment plants have a negative effect on the drainage qua-
lity of the purified water. These must therefore be detected
without delay and rectified by yourself or by a qualified main-
tenance firm. So as to keep a record of your self-inspections
you are obliged to keep an operations diary. At the end of
this manual, you will find a master copy that contains all the
necessary specifications.
The water authority may demand to look at this operations
diary. In detail, you are requested to regularly carry out the
following inspections:
Monthly inspections
• At the control: Carrying forward the operating times on the
display into the operations diary
• At the preliminary sedimentation: inspection of the floating
sludge on the water surface. If necessary, this must be
drawn off or broken up with clear water. No sludge may
enter the aeration chamber in an uncontrolled manner.
The sludge must be disposed off at the latest when 70%
of the intake capacity has been reached. Measuring the
thickness of the sludge layer is carried out similar to mea-
suring the oil level on motorcars. Use a long stick or simi-
lar implement. This is plunged into the preliminary sedi-
mentation chamber down to the bottom of the tank. The
measuring tool is then removed from the tank and the
sludge layer can be measured. An exact measurement can
be carried out by qualified personnel.
• At the aeration chamber: visual inspection of the draining
water for clearness
• Visual inspection of the mixing process and the input of air
bubbles
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