Rainwater reservoirs, desalinators, wastewater reuse: no shortage of solutions, no more time to waste

Endless drought emergency in Europe and Italy, where many agricultural activities are at risk of survival. According to Coldiretti, fields have already lost an average of 1/3 of production of fruit, corn, wheat, rice, and milk, with peaks of 45 percent for corn and animal feed fodder. The areas bordering the Po, which are particularly fertile, are witnessing the disastrous effects of the rising salt wedge, which has now reached 30 kilometres from the river delta, i.e., the upwelling of salt water from the sea as it makes its way into the aquifer due to reduced river flow.  

By now, it is clear that climate change does not allow us to simply wait for more favourable weather conditions, but structural actions must be considered that are sustainable and ensure environmental protection.  

Coldiretti's rainwater reservoirs and Webuild's desalinators

Infrastructural interventions will be needed to avoid, as is the case now, dispersing along the aqueduct network one-third and even more of the water transported, a problem that is well known but has never been addressed. But in our country only 20 percent of water withdrawals are for domestic use, while 25 percent go to the industrial sector and more than 50 percent to agriculture. Coldiretti then proposed the creation of a vast network of reservoirs to collect rainwater, while Webuild launched a proposal to use desalinators.

In Italy, it is still a solution relegated to a niche, but it is a well-known tool in the Middle East (where Webuild has built several with its subsidiary Fisia Italimpianti) and Israel, where it guarantees survival. And it is also widespread in Spain, where more than 700 desalination plants produce more than half of the drinking water, and in California and in Australia, which decided to make massive use of these plants precisely after a period of unprecedented drought.

And, speaking of desalinators, it is worth mentioning that in the province of Rovigo they had to run for cover by renting one from Spain that will cost 150 thousand euros for two months: with a capacity to desalinate 100 thousand litres per hour, it will provide drinking water to 5 thousand people. 

Innovation can also contribute, as demonstrated by the circular economy example implemented by Webuild itself, in Piedmont, where work on the Turin-Lyon rail link is advancing. For the entire period of the water emergency, the mountain water collected in the first section of the Maddalena Tunnel - currently fed back into the Dora River - will in fact be destined for the Chiomonte Irrigation Consortium, which will thus be able to count on sufficient water resources to irrigate 12 hectares of vines in the area.   

Wastewater, a valuable but underutilized resource

For agricultural and industrial uses, wastewater reuse is also of great interest. According to Arera, the industry authority, only 4 percent of purified wastewater is valorized compared to a potential of 20 percent. While one research centre's study indicates that-for agricultural use alone in areas adjacent to sewage treatment plants, just under 5 billion cubic meters of purified water could be reused each year, covering about 45 percent of the irrigation demand in our country.  

This activity was regulated by the European Union two years ago with a text that will come into force in June 2023. Italy must run, because the working group composed of representatives from the Higher Institute for Environmental Research and Protection (Ispra) and the Ministry of Ecological Transition (Mite) has just begun work on a law to set criteria for wastewater reuse and to define who is responsible for burdens and management.