The BAC-process for treatment of waste water containing non-ionogenic synthetic surfactants

In this paper experimental results on the biological-activated carbon (BAC) -process for biological degradation and adsorption of non-ionogenic surfact ants (NISS) in the waste water treatment are discussed. It is shown that th e mechanism of the BAC-process is not the simple addition but the synergeti c combination of biodegradation and carbon adsorption. The major aspects of such synergism are the biological regeneration (bioregeneration) of the ad sorbent and the reduction of the toxic effect of waste water contaminants o n microorganisms. It is shown that the basis of the bioregeneration process is the desorption of substances previously adsorbed on the activated carbo n. The desorption from micropores takes place because of the reverse concen tration gradient, due to the microbial degradation of waste water contamina nts in the liquid phase. The desorption from mesopores is also supported by the activity of microorganisms exoenzymes. Thus, the process of bioregener ation is featured by two noncontradictory hypotheses. (C) 2001 Elsevier Sci ence Ltd. All rights reserved.