Irrigate fields while protecting the water resources

Milan, the capital of Italy’s Lombardy region, is considered to be the country’s economic heart. Criss-crossed by the Po river and its tributaries, the region nonetheless suffers from periods of harsh drought. The surface water tables are not sufficiently regenerated while the irrigation of agricultural crops consumes almost 70% of local water resources.


To manage recurrent droughts and support its agricultural industry, the Milan authorities turned to SUEZ in October 2001. The main issue for the region was to implement a sustainable crop irrigation solution that would preserve water resources, namely

  • produce water for agricultural needs in sufficient quantities and quality, even during dry periods;
  • limit the environmental impact of the water production plant built in a protected agricultural area.
of crop growing land to be irrigated
the record time taken by SUEZ to design and build a water plant for agricultural reuse

Recycling wastewater, an alternative resource for irrigation

Irrigate crops using recycled wastewater: the solution delivered by SUEZ to secure the supply of irrigation water while preserving the natural resources available. To achieve this, we designed and built the Milan San Rocco wastewater treatment and reuse plant in 2004 and operated it until 2013.

Guarantee producers and consumers soundly irrigated crops

SUEZ delivered its capacity to innovate and its expertise in sustainable management of the water cycle to serve the Milan region. The Milan wastewater treatment plant ensures:
  • that treated water destined to irrigate crops for use in the food chain is harmless, due to ultraviolet disinfection techniques

  • respect of standards specific to sensitive natural areas, using complementary mechanical and biological processes which control the levels of nitrogen and phosphates

For local inhabitants, going beyond environmental regulations

As the Milan San Rocco wastewater treatment plant is located in a protected agricultural area, it blends seamlessly into the environment: 
  • two towers treat the air as the water is treated, before discharging it back into the environment
  • the plant generates no olfactory, visual or noise pollution in its natural surroundings
  • the most: recovery of sludge from wastewater treatment, as an alternative fuel in industry, in a logic of circular economy

The results

SUEZ offered Milan the largest alternative water resource in Europe. Its sustainable management of the water cycle reconciled economic issues with protection of the fragile natural environment; agriculture was given a boost and the balance of the surrounding ecosystem was re-established.

In dry periods, all recycled wastewater is used to irrigate 22,000 hectares of crop fields. In summer 2006, this saved up to 80% of maize and rice crops according to estimates by local farmers.

The technologies developed by SUEZ enable Milan's farmers to return to their vegetable growing traditions. Food crops that were sensitive to water quality (tomatoes, potatoes, certain rice varieties) had been stopped because of the organic pollution of the river water and the poor quality of wastewater treatment. They have all been resumed. Fish and frogs that had disappeared returned to the surrounding rivers, fresh water fishing was reopened.  

wastewater recycled during periods of rain
wastewater treated every day, equivalent to the water consumption of one million residents
air treatment capacity before return to surrounding environment