CETIM have led a European research project, in alliance with EMAFESA, MAGTEL, SOCAMEX and the University of Barcelona, to develop a technological solution based on membranes for the innovative secondary treatment of wastewater.

Final meeting of the project, held in Almendralejo (Extremadura).

Water scarcity is one of the major problems threatening human life on Earth and industrial activity. Drought is becoming increasingly common over larger areas and for longer periods of time. This situation particularly affects sectors such as agriculture, causing a drop in production and, consequently, higher prices in the shopping basket.

In order to find solutions to alleviate water stress, at CETIM we have led LIFE GREEN SEWER, our recently completed project in which we have designed, built and validated a pilot plant for the secondary treatment of wastewater using membrane technologies, as well as for the recovery of energy and nutrients.

The pilot plant was first installed at the Ferrol WWTP in Galicia, managed by project partner EMAFESA. After the promising results obtained in this first location with a typical Atlantic climate, the LIFE GREEN SEWER system was moved to the WWTP of Almendralejo, in Extremadura, managed by SOCAMEX, another partner of the initiative. The purpose of the validation in this case was to learn about the effectiveness of the technologies developed in a much drier and hotter climate and in an area rich in agricultural activities.

Class B reuse water

The results obtained in LIFE GREEN SEWER are in line with European legislation (Regulation (EU) 2020/741 of the European Parliament and of the Council of 25th May 2020). This regulation establishes minimum water quality and monitoring requirements, as well as provisions on proper risk management, for the safe use of reclaimed water for agricultural irrigation in the context of integrated water management.

In accordance with the parameters of this regulatory framework, LIFE GREEN SEWER has obtained class B reuse water, it says, water can be reused on food crops that are consumed raw when the edible part is produced above ground level and is not in direct contact with reclaimed water, as well as on processed food crops and non-food crops (including crops used to feed dairy and meat producing animals). Under this label, all irrigation methods are covered. In addition, the project has produced a stream with high value nutrients present in the water, such as nitrogen, phosphorus or potassium, with the potential to recover fertilisers for use in agriculture.

Interior of the pilot plant developed at LIFE GREEN SEWER.

The different water characteristics of the two locations where the technology has been validated increase the replicability of the project. For example, the wastewater from Almendralejo contains a higher amount of organic matter due to the high presence of the food industry in the area, which favours a higher production of biogas and the generation of effluents rich in nutrients.

We have also used Life Cycle Analysis and Cost Analysis to examine both the environmental and economic feasibility of implementing this technology on a large scale. The data shows that, if we were to treat the water of 10,000 inhabitants with the LIFE GREEN SEWER solution, it would be environmentally cost-effective and would also reduce the economic costs compared to current traditional water treatment processes.

Thanks to this research led by CETIM in alliance with EMAFESA, MAGTEL, SOCAMEX and the University of Barcelona, as well as co-financing from the European Commission under the LIFE programme, great advances have been made in these water treatment technologies.