Dow project seeks to promote reuse
Dow Water & Process Solutions, is participating in one of ten European Commission-funded projects that aim to stimulate innovation and improve cohesion in Europe's water reuse sector.The company has a major role in the Demoware project which looks to demonstrate how water stress in a European region can be mitigated by fostering industrial water reuse, with emphasis on cooling towers.
The three-year project is due to end in December 2016. It is focused on novel technologies for wastewater reuse and it includes the treatment, in the Camp de Tarragona Advanced Water Reclamation Plant (CTAWRP), of wastewater from the Spanish cities of Salou, Tarragona and Vilaseca.
The plant is operated by Veolia and the government owned water supplier to the Camp Tarragona petrochemical complex, AITASA.
The reclamation plant uses Dow's FIlmtec reverse osmosis elements following pre- treatment using Veolia's Actiflo product. The treated water is then redirected to various plants in the complex for use in their industrial processes, instead of being discharged into the Mediterranean as it had been previously.
Dow's Europe, Middle East and Africa commercial director, Alexander Lane, said: "This project constitutes an important milestone to improve the efficiency of the European industrial sector, while also improving municipal processes."
Dow's main goal with this project was to develop a system to treat wastewater to a high enough quality to be used in cooling towers for the companies in the Camp Tarragona petrochemical complex.
Ppreviously they used fresh water from the Ebro River placing a strain on the river and the surrounding municipalities in one of the most water stressed areas in Spain.
The project frees up fresh water resources and increases water availability for municipal, tourism growth projects or agriculture uses.
As a result of the project, the water used in the cooling towers at Dow Chemical's ethylene cracker is 40% reclaimed water - 160 m³/h of reused wastewater from the reclamation plant. By the end of 2016 Dow anticipates the cooling water will be 90%, blended. Prior to the use of treated wastewater, the Dow cracker cooling tower ran solely on Ebro river water.
The higher quality of the recycled water compared to the river water means the cooling tower can be operated at seven cycles of concentration in summer compared to four when using Ebro water. This, along with the anticipated increase in the percentage of reclaimed wastewater in the cooling tower feed, could allow the system to operate in an almost closed loop.
A combination of Dow's Filmtec Brackish Water Extra Fouling Resistance and Brackish Water Low Energy (LE) reverse osmosis elements were installed in the double pass plant of the CTAWRP. The Extra Fouling Resistance membrane elements were used in the first pass. This and the second pass with Low Energy membrane elements produced high salt rejection at 33% lower pressure, as well as excellent silica, boron, nitrate, isopropyl alcohol and ammonium rejection said Dow.