Use of membrane bioreactors for the bioremediation of groundwater polluted by chlorinated compounds

The aim of this experimental work has been the application of a new polluted waters treatment technology for the selection of a bacterial population capable of bioremediating a synthetic groundwater polluted by four different chlorinated compounds. The innovative technology applied in this study was the biological treatment system known as MSBR (Membrane Sequencing Bioreactor), which consists of a Sequencing Batch Reactor (SBR) coupled to a membrane module for the filtration of the biological sludge that degrades the chlorinated compounds present in the polluted water fed to the system. The synthetic groundwater used in this experimentation contained four chlorinated compounds: 1,2-dichloroethane, 1,2-dichlorobenzene, 2-chlorophenol and trichloroethylene. During the development of the research, the chlorinated compounds were fed either alone on in different mixtures in order to identify possible effects of each substrate on the degradability of the others. Some operational parameters were varied in order to check the possibility of implementing the system at a larger scale. The MSBR system equipped in this study was effective in the acclimation of a sludge to hardly biodegradable xenobiotic compounds, and the degradation rates achieved were comparable to other similar studies performed, even if in this experimentation, differing from all the others found in literature, good removal rates were achieved for the degradation of the substrates when they were fed in mixtures.