Verónica García Molina, EMEA Technical Service and Development Manager, Tarragona Global Water Technology Center R&D Manager
Alfred Arias, Dow Ibérica Innovation Support & Learning Leader
Dow Water & Process Solutions
Situated in a water-stressed region of Spain, the Camp de Tarragona petrochemical complex and surrounding municipalities face competition for freshwater resources to meet growing agricultural, industrial and residential demands. The complex previously used freshwater from the UNESCO-protected Ebro River Basin to power its industrial processes, but desired a more sustainable option to ensure a reliable water supply for operations.
The Camp de Tarragona Advanced Water Reclamation Plant, operated by Veolia Environnement S.A., Aguas Industriales de Tarragona S.A. (AITASA) and the government-owned Catalan water agency, L’Agència Catalana de l’Aigua (ACA), collaborated on a plan to reclaim and reuse municipal wastewater for industrial use. The Dow Chemical Company (Dow) joined the project as one of the end-users of the reclaimed water as well as a member of the project.
This project became one of the few European Union-funded DEMOWARE projects to stimulate innovation and improve cohesion in Europe’s water reuse sector. Of the several sites involved in DEMOWARE, the Camp de Tarragona project is the only industrial site.
This project uses treated municipal wastewater from the Spanish cities of Salou, Tarragona and Vilaseca. The wastewater from these cities is processed and purified by the water reclamation plant to the required quality before redirecting it for use in industrial processes instead of discharging it into the Mediterranean Sea.
Veolia’s technology is used as a pre-treatment followed by DOW FILMTEC™ BW30XFR-400/34i extra fouling resistant membranes in the system’s first pass and DOW FILMTEC™ LE-440i1 low energy membranes in the second pass. These membranes offer stable quality permeate, while the extra fouling resistance feature increases equipment lifetime and reduces operational expense, as fewer cleanings are needed. The design of the second pass with low-energy membranes has helped the plant deliver higher salt rejection at 33 percent lower pressure, reducing overall energy use.
Through the project, Dow also wanted to develop a treatment system to produce wastewater of a quality for reuse in cooling tower operations. Dow’s ethylene cracker cooling tower had been running solely on pre-treated water from the Ebro River. Now, the cooling tower uses up to 40 percent reclaimed water (160 m³/h), and has reduced chemical usage by 23 percent. Depending on the season, this frees up more than 200 m³/h of water rights for the municipality.
In addition, the site’s cooling towers have increased the number of cycles they can operate with the same amount of water without scaling, corrosion or bio-growth tendency. Cooling tower blowdown has also been reduced by 49 percent.
With the DEMOWARE project, Dow is helping minimize water stress, increasing freshwater availability to meet municipal, tourism and agricultural needs, and contributing to the preservation of the Ebro River Basin. The move towards a closed loop water system for the industrial complex is offering positive environmental impact and business value. The final target is to serve 90 percent of the Camp de Tarragona complex’s water demand with reclaimed water.
As a growing population and urbanization place increasing demands on freshwater, the project is a model for how the reuse of municipal wastewater can be a reliable and safe option to help mitigate water scarcity.
Note: The DEMOWARE Consortium is framed under the European Research and Development funded 7th Framework Program, led by CTM (Centre Tecnológic de Manresa), under the FP7-ENV-2013-WATER-INNO-DEMO Call with the Grant Agreement no 619040.
1 The DOW FILMTEC™ LE-440i Element has since been discontinued. Speak to Dow about other DOW FILMTEC™ low energy elements: www.dowwaterandprocess.com/contactus.