Membrane processes are becoming popular in downstream processing plants for the production of boiler feed water, treatment and recycling of wastewater and integration into various processes. The design and efficiency, both hydraulically and in terms of energy, are improving rapidly Design changes such as heating feedwater through solar ponds can result in up to 35% reduction in energy requirements' Membrane development, energy recovery and pumping efficiency all contribute to reducing the cost of operation every year.
However, along with all these improvements, membrane processes still suffer from a number of chemical and physical problems. Higher recoveries, which concentrate salts and exceed their solubility, result in scaling potential. Higher flux rates introduce more water per metre squared of surface area, also resulting in increased fouling potential. Environmental conditions within the membrane are ideal for bacterial proliferation, which can cause high biofouling potential. Higher throughput has accentuated the impact of other contaminants such as biopolymers, which are harder to test for and remove during pretreatment processes.
All of these potential conditions will, if they occur, result in decreased efficiency, shorter plant life and higher operational costs.
Developments to address industry needs
Kurita Europe GmbH, a subsidiary of Kurita Water Industries of Japan, has dedicated much of its research and development investment into solving many of these problems, which can impact and increase the total cost of operation for companies utilising membrane processes. In this article the basic approach and some previous case studies have been described to support the solution in each case.