Pentachlorophenol (PCP) is a biocide used as wood preservative. It was extensively used as a wide spectrum pesticide until its prohibition in 2004 by the Rotterdam Convention. Large quantities of PCP are also produced from ECF-type paper pulp bleaching, the most commonly used nowadays (Savant et al., 2006). Due to its toxic character, PCP is of environmental concern since it acts on a variety of organisms as a potent inhibitor of the oxidative phosphorylation. It disrupts the proton gradient across membranes, interfering with energy transduction of cells (Chen et al., 2008). Moreover, its carcinogenic potential has been recently demonstrated (Cooper and Jones, 2008). The use of this chemical over decades, its resis-

Reprinted from Bioresource Technology 140, Lopez J, Monsalvo VM, Puyol D, Mohedano AF, and Rodriguez JJ, Low-Temperature Anaerobic Treatment of Low-Strength Pentachlorophenol-Bearing Wastewater, pp 349-356, Copyright 2013, with permission from Elsevier.