EXTREME DROUGHT EVENTS AND THE USE OF TREATED WASTEWATER

In 2017 Portugal faced an extreme drought period. By the end of October, Portugal was under severe or extreme drought levels. In fact, some cities on the North of the country received emergency water supply by fire trucks.

In this context, and taking into account the relevance of the issue, in 2017 an educational campaign for saving water was implemented by the Portuguese Environmental Ministry. This campaign was extended to 2018 with some measures to be implemented in near future by companies, utilities and municipalities.

This drought period increased awareness levels and forced cities and utilities to be better prepared for the similar occasions in the future and to ensure that water and wastewater services are resilient and sustainable.  Also, another lesson learnt was that the use of treated wastewater for non-potable uses is a source of water that needs to be considered.

Nowadays, Águas do Tejo Atlântico, SA (AdTA), the multimunicipal wastewater system of Great Lisbon and West, counting with 104 WWTP and providing water to 2,4 million Inhabitants, uses treated wastewater in its core activities, for cleaning and for internal irrigation and for street cleaning in some municipalities, such as Lisbon and Loures. However, the use of treated wastewater in external uses is sometimes misperceived.

AdTA has been developing measures aimed to increase the use of treated wastewater in collaboration with its stakeholders, such as municipalities and miscellaneous end-users, always focused on ensuring the best possible quality of treated wastewater.

In this context, AdTA is also developing projects to improve the treatment in the WWTP for treated wastewater, based on the concept of multiple barriers to remove the pollutants, physical, chemical and residual and promoting different pilot tests in its facilities.

In addition to that, in the first semester of 2018 AdTA participated in 3 proposals for R&D projects (PRIMA funding) with the topic “Water reuse and water desalination for agricultural and food production” to test and study the impact of using treated wastewater and also for working on the public acceptance of treated wastewater. In March 2018, AdTA participated in a proposal with Câmara Municipal de Lisboa as coordinator, to a Urban Innovation Action fund, in order to Close the Urban Water Cycle in Lisbon city to guarantee the sustainability and resilience of the city to water scarcity, by using recycled water for non-potable uses in an impactful urban scale.

Finally, AdTA is constantly collaborating with municipalities to develop some use/pilot cases to test the use of treated wastewater on irrigation and cleaning streets to support and overcome the barrier of lack of legislation and regulation. 

The role of wastewater utilities to supply treated wastewater for non-potable uses and therefore to contribute for closing the urban water cycle and for water resource conservation is vital for increasing the resilience of the cities and their services. In the RESCCUE project, which precisely seeks to build more resilient cities to climate change impacts, AdTA provides a demonstration site for wastewater systems services in Lisbon city, one of the three project study cases, together with Barcelona and Bristol. The main roles of AsTA in RESCCUE project are related with inputs for risk and resilience scenarios; and operational strategies