San Marco Bioenergie installs Water Energy’s electrodialysis demineralisation system

San Marco Bioenergie – subsidiary of Gruppo Bioenergie and responsible for the management of the biomass power station located in Bando d’Argenta (FE, Italy) – has recently adopted an electrodialysis demineralisation system for the production of demineralised water aiming to improve the quality of the water used in the plant as well as the efficiency and the safety of the treatment process.

The electrodialysis demineralisation system installed by Water Energy is able to produce a demineralised water flow of 25 m3/h, continuously and all year long. The treated water supplied by the plant must comply with the following parameters in order to be suitable for the electrical power station:

– specific conductivity at 25°C, μS/cm: <0.07;
– silicon dioxide, ppm SiO2: <0.05;
– pH: between 6.5 and 7.5.

Electrodeionisation is a separation process using a flat semi permeable membrane charged by cathodic and anodic functional groups. The electrodes generating an electric field are located at the ends. The semi permeable membranes are alternated in the package allowing the ions to migrate under the influence of the electric field, concentrating in a separated flow. In order to achieve high demineralisation efficacy, the cells contain strong cathodic and anodic resins combined in order to simulate the behaviour of a mixed bed. These resins are regenerated by the hydrogen and hydroxide ions produced when water dissociates under the influence of the electric field.

The advantages of this treatment are remarkable:

– production of high-purity water;
– elimination of regeneration chemicals and of neutralisation tanks (compared to conventional mixed beds);
– reduction in space use;
– continuity in operations;
– constant quality of the produced water.

The two EDI lines installed by Water Energy and carrying the General Electric trademark, are the core of the SMB power station water treatment system. These are in line and can operate both singularly and simultaneously.

Read the full article on ipcm® International Paint&Coating Magazine n. 33.