Italy's Underground Water Plant
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SOME 35,000 CUBIC METRES of rock were excavated from inside Bardello Mountain to
accommodate this water treatment plant. Six mulit-walled sand filters are shown here.
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TREATED WATER is pumped to a storage tank through
S30400 stainless steel pipe, 400 millimetres in diameter.
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UNTREATED WATER FROM LAKE Como is pumped underground through
S30400 stainless steel pipes, 700 millimetres in diameter.
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THE USE OF CORROSION-RESISTANT nickel stainless steel should result in lower maintenance. |
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The Italian tourist town of Como has built an underground drinking water plant that uses
nickel stainless steel, ensuring corrosion-resistance and low maintenance.
Nickel magazine, February 2003 -- For about 20 years the citizens of Como,
Italy, have drawn water from their lake as an alternative source of drinking water. When
demand for water increased, the municipal company ACSM decided to build a high-capacity drinking
water plant rated at 33,000 cubic metres per day.
What's unusual about the plant is that it's in an underground cavern in Bardello Mountain, which
dominates the town. The plant takes water from Lake Como and brings it up to drinkable
standards through treatment with ozone and chlorine dioxide, and in a large-enough quantity to
meet the increased demand.
The 20-million-Euro plant began operation in January 2001, and Lake Como has since become the only
source of drinking water for the entire town. ACSM says the citizens have accepted the change
and are satisfied with the quality of the water.
The plant was constructed inside Bardello Mountain for two reasons: first, it is hidden from view, which is important for a town that attracts a high number of tourists, and second, it does not occupy valuable urban real estate.
The climate inside the cavern is very humid. Metal surfaces easily reach the air dew point and become
wetted by condensation, thus rendering them susceptible to corrosion. It was in order to prevent this
that ACSM selected nickel-containing stainless steel for piping, flanges, fittings and nuts and bolts. Pipe
diameters range from 400 to 700 millimetres and wall thickness from 3 to 4 millimetres. A total of 958 metres
of pipe were used.
The inside faces of these components resist corrosion in all stages of the water
treatment process, leaving the quality of the water unaffected, while the outside faces are
likewise resistant, even though they are constantly wet.
The use of nickel stainless has enabled ACSM to minimize maintenance costs and avoid interruptions to the plant's operation. Two varieties, S30400 and S31600, were used, 49 tonnes of the latter in the ozone section of the plant.
Adapted, with permission, from the December 2002, No. 150 edition of "Inossidabile"
published by Centro Inox, the Italian Stainless Steel Development Association.
Photo: CENTRO INOX
 Centro Inox |
