Alkylphenol and alkylphenol polyethoxylates in water and wastewater: A review of options for their elimination

During the last 10years, the appearance of emerging organic compounds described as endocrine disrupters in wastewaters and water resources has become a major concern for both society and public health authorities, the whole industrial world and the agricultural sector. Endocrine disrupting compounds are found in various environmental compartments such as water, sediments, soils and atmosphere, as a result of their wide usage. Numerous products are concerned including surfactants, industrial additives and formulations, pharmaceuticals, and also personal care products. However, the existing conventional water treatment plants were not designed for these new contaminants. In the present study, an overview of the literature on methods for the elimination (removal and/or degradation) of emerging trace organic contaminants is presented. This review is limited to details of the treatment of one class of endocrine disrupters, namely alkylphenols and their polyethoxylate derivatives, which are suspected to interfere with the hormonal system of wildlife. The technologies proposed for alkylphenol treatment include membrane treatment using biological (membrane bioreactors) or physical processes (membrane filtration such as nanofiltration), biotechnological-based methods (biofilms, immobilized enzymes, etc.), adsorption-oriented processes using conventional (activated carbons) or nonconventional adsorbents (clays, cyclodextrin, etc.), and advanced oxidation processes (photocatalysis, photolysis, and sonochemistry). Examples are taken from the literature to illustrate various features of the technologies used in decontamination methods. Among them, photocatalytic oxidation is an interesting tool for alkylphenol treatment due to its potential to reach complete mineralization.