BIOLOGICAL DETOXIFICATION OF A 3-CHLORONITROBENZENE MANUFACTURE WASTE-WATER IN AN EXTRACTIVE MEMBRANE BIOREACTOR

A novel membrane bioreactor has been used to extract and biodegrade nitrobenzene (NB) and 3-chloronitrobenzene (3CNB) from an industrial wastewater arising in 3-chloronitrobenzene manufacture. This wastewater has a pH of less than 1.0 and an inorganic salt concentration of >5% w/w and so would require some form of neutralization and pretreatment prior to conventional biological treatment. In contrast, using the membrane bioreactor the wastewater was successfully biologically detoxified without any form of pretreatment. The reactor system operated continuously for over 600 h and pollutant removal efficiencies of over 99% were observed at wastewater residence times of approx. 30 min. This was achieved through the use of a selective membrane in conjunction with specialized microorganisms enriched to degrade the target compounds. The NB and 3CNB were extracted from the wastewater across this membrane and biodegraded in an aqueous biomedium phase. The membrane bioreactor configuration described offers a range of advantages over conventional bioreactors due to the fact that there is no direct contact between the wastewater and the microorganisms.