Install the raw water pump as close to the intake place as possible. Connect one or
two raw water suction hoses with strainer, protective basket and plastic float with
chain on suction side. Secure the suction valve and hoses with an arrester cable.
Hang the raw water inflow pipe into the first raw water tank and connect it to the raw
water pump with a corresponding number of raw water pressure hoses. The raw
water inflow pipe is alternately hung into all raw water tanks which are then being
filled.
Now the four raw water tanks have to be coupled to the raw water collector with
additional raw water suction hoses. It has to be checked that all four ball valves of
the raw water collector are closed.
IV 1.2 Operation/pretreatment unit
The raw water pump can be started acc. to the operating instructions for filling of
the first raw water tank (see VII).
While the first tank is being filled, one prepares the treatment chemicals (chlorine,
ferric chloride, activated carbon, lime) acc. to the respective standard dosing plan
in the 17 l buckets filled with raw water. Take care that the chemicals are never
added to the raw water tanks in undissolved condition. They should always be
dissolved and stirred in a 17 l bucket filled with pure water or, if not otherwise
possible, with raw water.
First fill in the water (approx. 10 l), then add the chemicals.
If the water level in the first tank has reached the knee at the raw water inflow pipe,
one adds the first chemical (chlorine). One proceeds with the other chemicals
(ferric chloride, activated carbon, lime) acc. to the standard dosing plan. Each time
adding chemicals one has to stir vigorously with the paddle so that the chemicals
are well distributed. (If available, the stirring can also be carried out with an air
pipe.)
If the raw water tank is filled, one throttles the raw water pump and hangs the raw
water inflow pipe into the next raw water tank. Here one proceeds just as with the
first raw water tank. The same applies to the third and fourth raw water tank.
After each filtration of a raw water tank a sludge layer remains. The new filling can
then be carried out as described in point IV 1.2 (use of the contact sludge). After
about 5 - 10 new fillings the sludge is drained off the tank.
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