Future perspectives in bioreactor development

The paper discusses conversion capacities of both anaerobic and aerobic was tewater treatment systems in relation to growth kinetics, hydrodynamics and biomass concentration. In the current modern anaerobic high-rate reactors the conversion potentials are optimally exploited. This is not yet true for aerobic systems since operation of aerobic systems under conditions of low biomass growth reduces the maximum applicable loading rates significantly. Both the concept of granulation and the introduction of fluidised bed syst ems have increased conversion capacities for both anaerobic and aerobic sys tems significantly. One of the latest development concerns the SBR with gra nular biomass. The grazing concept, in which ciliates convert aerobically g rown dispersed cells, offers a possibility for significant improvement of a erobic systems. In the fields of psychrophilic and thermophilic anaerobic t reatment, specific reactor development may contribute to further enhance vo lumetric conversion capacities. Due to reduced water usage, both COD and sa lt concentrations tend to increase for industrial effluents. As a consequen ce, there is a need for the development of anaerobic reactors retaining flo cculant biomass. The membrane bioreactors offer a solution for certain nich es in wastewater treatment. However the oxygen transfer economy is poor. Th ere is a need for fundamental knowledge development to obtain a realistic i mage of this technology.