Bioreactors for Environmental Applications

Rautenbach and MeUis [75] describe a process in which a UF-membrane fermentor and a subsequent NF-treatment of the UF-permeate are integrated. The retentate of the NF-step is recycled to the feed of the UF-membrane reactor (Fig. 13.8). This process has been commercialised by Wehrle-Werk AG as the Biomembrat -plus system [76] and is well suited for the treatment of effluents with recalcitrant components. The process also allows for an additional treatment process, like adsorption or chemical oxidation of the NF-retentate, before returning the NF-retentate to the feed of the UF-membrane fermentor. Usually, the efficiency of these treatment processes is increased as the NF-retentate contains higher concentrations of these components. Pilot tests with landfiU leachates [75] and wastewater from cotton textile and tannery industry have been reported [77]. An overview of chemical oxygen demand (COD) reduction and COD concentrations in the permeate are shown in 

Compound to be removed from air Cone. [ppm] Type of membrane Nutrient supply in liquid Bio- film Inoculant Ref 

Dichloroethane 150 Silicone spiral wound Minerals Yes Xanthobacter GJ10 72  

Trichloroethene 20 Polysulfone fibers Acetate, minerals Yes Sludge 74 

Reactor in a combination of a membrane bioreactor and a bubble-column and was designed for simultaneous degradation of both hydrophilic and hydrophobic contaminants from the gas phase. 

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Almeida, J. S., Reis, M. M. and Crespo, J. G. 1999. Development of extractive membrane bioreactors for environmental applications. Environment Protection Engineering, 25,111-121. 

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