Interviews

Journey into the water pipes with MM


water, running water, mayor's water. For ordinary citizens, a tap opens and everything flows, but for those who manage the service, like Milanese subway in Milan, it's not all that simple. Rather. Yet levels of excellence can be achieved. Stefano Cetti, general manager of MM, which is entrusted with the entire service of the great Milan, reveals some mechanisms, and the good quality of the tap water, which is very controlled.

1) What is your role within the Milanese water service? What are your functions and areas of expertise?

The water service has been entrusted in its entirety to MM by the Municipality of Milan since June 2003 and concerns all three sectors of which it is constituted, or aqueduct, sewerage and purification.

The aqueduct service includes all the phases and activities necessary to provide users with water suitable for human consumption, in accordance with the provisions of current legislation and in particular by Legislative Decree 31 of 2001, i.e. processes of collection, treatment, distribution and control activities, as well as a bill to users.

MM also deals with the implementation of the Investment Plan relating to the infrastructure necessary for the performance of the service.

2) Network leaks: what kind of monitoring do you do and with what results?

About 20% of the network is monitored every year and any leaks found are repaired; the level of overall losses, i.e. physical losses from the network and those attributable to an under-measurement of the water distributed, stands at values ​​of 10-12%, compared to a national average of over 30%.

3) Polluted groundwater: what kind of substances did you find? How do you check?

Inorganic micro pollutants have never been recorded, neither as regards contamination nor for exceeding the inorganic parameters provided for by Legislative Decree 31/2001. The organic, on the other hand, are present in the stratum with variable concentration and are the consequence of residual pollution from industrial production in the city. There are halogenated volatile organics, volatile aromatic hydrocarbons, halogenated semivolatile organics, pesticides and assimilable products and nitrates (of anthropogenic origin).

The SII is equipped with a laboratory capable of carrying out strict chemical and biological checks on each parameter required by current legislation (Legislative Decree 31/2001), the routine control program of chemical parameters, in agreement with the Control Bodies (ASL , AATO), provides for: 3 weekly checks on the hygiene taps of the operating units; 1 check every 3 weeks of the 40 fountains in the city; 1 control per year at the active and purging wells of each active plant; 1 check per month at the SPIA wells located upstream and downstream of the active plants; 1 check per month at the tap placed on the well supply pipe of plants that do not have treatment systems and 1 check per month at the inlet / outlet of the treatment systems.

4) With what actions do you contain your waste production? ? With what results?

As regards the sludge produced by the purifiers, we obtain a reduction in the volumes to be disposed of as most of them undergo a thermal drying process which reduces the volume by about two thirds and makes them suitable for use as fuel in cement factories.

5) Promotion of the use of water in agriculture and for domestic use: how do you act?

Most of the water purified by the two plants in Milan Nosedo and Milan San Rocco are used for irrigation (approximately 90,000,000 cubic meters per year), thanks to the advanced treatment system that allows compliance with strict regulations.

In this field, Milan is the most significant example at a European level and, practically unique in Italy (irrigation contribution to an agricultural area of ​​more than 100 square kilometers downstream from the city).

6) What emerges from the monitoring of the purification areas you carry out: soil, water and air?

The protection of the surrounding area and the overall improvement of the ecosystem, in particular as regards the quality of the purified water returned to the environment.

7) When and why was MilanoBlu born? What can citizens find there?

From December Milan Blue is the Milan trademark for the most common “Acqua del Sindaco”. To be even closer to users, the site has been activated where citizens can find all the information regarding the water that is distributed and the possibility of using useful services, such as carrying out procedures for the transfer of a contract or request for a new connection.

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