Spring water treatment with ultrafiltration and stripping

This study focuses on an hybrid process which couples ultrafiltration and stripping. The aim is to treat spring water to disinfect it and to enhance its pH without adding reactants. The first part of the study focused on stripping in a batch stirred reactor without UF. Air was chosen as the stripping gas, and the influence of the air flow rate on the water quality was studied for the stirred reactor and then for the hybrid process. Benefits of gas sparging have previously been pointed out in terms of fouling removal. This study demonstrates that gas sparging can be used to enhance the pH by removing a dissolved compound by gas stripping. Very good mass transfer coefficients are obtained in comparison with conventional systems like the batch stirred reactor or bubble columns.

A hybrid process coupling air sparging and UF obtained the required water quality for spring water without adding chemicals to the system. The membrane was used to remove bacteria and viruses. In the same time air sparging strips the CO2 with very good transfer coefficients in comparison with conventional stripping systems (bubble columns or stirred cells) and in reaching a good pH. It could also in the same way prevent fouling, should this be important. An industrial plant is now being built which is based on this innovative process. Long-term data will be available to validate the interest of the process and its impacts on the water quality.