The first membrane bioreactor plant (MBR) in municipal wastewater application was put into operation almost twenty years ago. Initial euphoria over the establishment of a new standard of treatment with this highly developed technique was very quickly followed by disillusionment. The high level of energy demand, which was the focus of investment decisions, led to conventional treatment technique winning out over membrane technology. Added to this may be a lack of open-mindedness of decision makers and potential operators towards this procedure.
If, however, one is concerned with current environmental challenges, it is hard to overlook the steadily growing list of advantages of membrane systems as compared with conventional treatment methods (figure 1). With each new item of information about new polluting substances which are shown to exert direct or indirect burdens on surface water or groundwater, expectations for the future cleaning performance of wastewater treatment processes increase. Multiresistant pathogens, anthropogenic trace elements as well as, more recently, microplastics, which have increasingly come into the focus of the public media, could be removed from the natural cycle in just one step with the deployment of membrane technology. At the same time, along with decreasing investment cost and operating cost of membrane plants, specific energy consumption has reached the level of an average conventional wastewater treatment plant. However, a more significant cost reduction on the investment side can only be expected with more widespread application of the procedure.
The robustness of the technology of conventional treatment plants, despite the enormous space required for the basin, has been up to now the decisive factor in the comparison with the more high-tech process technique of membrane treatment plants. The specialized qualifications required for membrane treatment plant staff underline a need for greater interest in control processes and machine technology. Otherwise, the same personnel requirements can be assumed for the operation of membrane treatment systems as for conventional plants.
The question arises as to which levels of cleaning and space requirements mark a clear and unmistakable threshold for choosing membrane technology for ecological and economic reasons. The new standards for operation of membrane systems developed in recent years simplify plant operation and increase cost-effectiveness. In the following table, original MBR planning and design specifications are compared with today's operating data and settings. A tremendous advance in process engineering as well as in the material development/design of the membranes is shown, with strong potential for a further rise in efficiency in the future...
Session: M7 - Process and Waste Water Treatment II
Day: 15 March 2018
Time: 13:00 - 14:15 h