Bioaugmentation: Possible solution in the treatment of Bio-Refractory Organic Compounds (Bio-ROCs)

Water quality is questionable when looking at the emerging pollutants that accumulate in hydrosphere day after day. In terms of water treatments to eliminate organic compounds, biological treatments are the most used technique, especially the conventional activated sludge (CAS) process. Unfortunately, several of these compounds such as petroleum and industrial wastes, some pesticides, pharmaceuticals, and hormonal substances appear to be refractory to such treatments and can join the different water surfaces from other natural environments especially contaminated soils. Physical and chemical treatments, in particularly the advanced oxidation processes (AOPs) are able to degrade some of these pollutants, but the nature and the possible effects of oxidation by-products remain controversial when complete mineralization does not occur. The aim of this article is to shed light on new and renewed biotechnological techniques recently introduced to resolve recalcitrance problem. Amending activated sludge with additional microorganisms able to produce versatile enzymes to enhance biodegradability or bioaugmentation, is gradually considered as a possible solution for the recalcitrance of Bio-Refractory Organic Compounds (Bio-ROCs). The use of this technique, traditionally in soil remediation field, and recently in water and sediments treatment is reviewed in this paper. (C) 2012 Elsevier B.V. All rights reserved.