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Acid
water, resulting from processes using acid washing (for example processes
on glass objects), can be treated with a manual or automatic neutralization
cycle, until the requested outlet level is reached. Usually,
acid water is stocked in two out-of-ground tanks for accumulation and
equalization. A pump draws from a tank and delivers in the other one in
order to keep the waste water shacked and equalized.
From the tank
mentioned above, acid water are sent to the chemical process tank by an
acid resistant pump. |
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Inside
the reaction tank a suspension of hydrated lime is proportioned by a suitable
pump, under the control of a pH-meter, while a slow stirring device mixes
the reagents with the waste water.
When the maximum
level of the reaction tank is reached, a level probe disconnects the inlet
pump and connects the outlet one, which sends the flood water to the flocculation
tank. A slow stirring device undergoes a mixing action, which helps the
flocking. These flocks will constitute the resulting mud.
The flood water
decants within the decanter, where the mud sediments on the conical bottom,
while clarified water emerges on surface.
Decanted mud
are sent to a filter-press. Water resulting from the filter-press process
is sent back to the system inlet, since it is still laden with sedimentable
solids.
The exhaust
of the decanted elements is recovered and pumped to a rapid filter with
quartzite bed, where possible sedimentable solids, escaped from decantation,
are held back.
After the quartzite
filter, water reaches the neutralization tank, where solution neutrality
is restored by dosage of sulfuric acid, under control of a pH-meter.
After the neutralization
process, water can be sent to the exhaust.
An electrical
box includes all the controls as well as the digital-electronic instrumentation
for the equipment correct running,. |