PROJECT DESCRIPTION
BACKGROUND
CERESTAR manages an important corn starch factory in Haubourdin (North of France). This is an industry that requires large quantities of demineralised water in the different stages of the process. For over 30 years, the Haubourdin plant has been using about 2 000 000 m3/year of city water for its industrial applications : water for steam boilers and process water. The city water is either softened or demineralised through a classical ion exchange resins process.
OBJECTIVES
The purpose of this project was to demonstrate a new membrane separation technique which would produce 600 000 m3/year of demineralised canal water (canal de la Deûle). No chemical was used for the reverse osmosis treatment, except for the membrane cleaning and protection operations. This project formed part of a general policy adopted by CERESTAR to utilise environment-friendly processes and to reduce water consumption. The main objectives were : - To decrease city water consumption in the Haubourdin plant by at least 35 %, by using water of a lower grade quality. - To substitute the classical demineralised water production process with a more environment-friendly technology: the reverse osmosis process eliminates the discharge of 2300 kg/day salt (sodium chloride) in the canal. - To implement a cheaper process for demineralising the water.
RESULTS
The process was analysed continuously, so that the canal water which was fed into the installation could be stopped immediately if there was an alarm. The overall process was automated and was handled by one person. From an economic point of view, with a production of 70m³ per hour of demineralised water, the cost per m³ fell from 0.90 EUR to 0.45 EUR. On a yearly basis, this means a saving of over 480,000 EUR, for an investment of around 5.2 million EUR (the old installation had to be replaced anyway). Yet, the profitability of this process from a strict economical point of view is questionable in the absence of financing such as that provided by the LIFE programme or by the regional water agency. Therefore it is clearly the environmental, rather than the economical benefits that distinguis this project. Despite some teething problems, the new process is now in operation and produces water with the quality required for the production of starch from maize. The water saving is in line with the original objectives. 764.000 m³ of water is produced every year from surface water instead of being bought from the distribution network of potable water. Furthermore, this process reduces the need to discharge salted waste (NaCl) into the canal by 808 tons/year. The process was analysed continuously, so that the canal water which was fed into the installation could be stopped immediately if there was an alarm. The overall process was automated and was handled by one person. From an economic point of view, with a production of 70m³ per hour of demineralised water, the cost per m³ fell from 0.90 EUR to 0.45 EUR. On a yearly basis, this means a saving of over 480,000 EUR, for an investment of around 5.2 million EUR (the old installation had to be replaced anyway). Yet, the profitability of this process from a strict economical point of view is questionable in the absence of financing such as that provided by the LIFE programme or by the regional water agency. Therefore it is clearly the environmental, rather than the economical benefits that distinguis this project. Despite some teething problems, the new process is now in operation and produces water with the quality required for the production of starch from maize. The water saving is in line with the original objectives. 764.000 m³ of water is produced every year from surface water instead of being bought from the distribution network of potable water. Furthermore, this process reduces the need to discharge salted waste (NaCl) into the canal by 808 tons/year.
