Reusing water for street cleaning is already equivalent to saving 1.2 million litres

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Guilherme Costa Oliveira

For the past eight months, the city's streets, vehicles and municipal bins have been washed using wastewater treated at the Freixo WWTP. A pioneering solution in the North has already enabled the Municipality of Porto to save 1.2 million litres of drinking water.

The project Água para Reutilização (ApR) (Water Reuse), which has been in operation since September last year, can produce 1,000 cubic metres of class-A water every day, thus saving drinking water and reserving it for consumption.

'This solution consists of a biological reactor with infiltration membranes. The water that passes through the WWTP system is sent to this system, which allows the water to be further purified and obtain a level-A classification, the highest for this type of use', the deputy mayor explained to Lusa.

Filipe Araújo believes that 'it wouldn't make sense to use drinking water' to clean public spaces, but that Portugal has a 'low level of reuse' and a 'long way to go' in this field, among countries with water scarcity problems.

In this way, the Municipality of Porto is looking to extend the solution to other users and customers in the city. The head of Environment and Climate Transition says that the aim is to use this water to irrigate gardens and parks, which are 'high consumers of drinking water'.

This will require the creation of a new piping circuit. 'We're trying to identify which private users we can have along the way to take this water to the parks and gardens', says the deputy mayor, adding that since the pipes through which this water and drinking water pass are not the same, 'we'll always have to build a parallel network'.

ApR is being developed by Águas e Energia do Porto with the support of the Portuguese Environment Agency and is the result of an investment of around 750 thousand euros.