Aqueous Waste Containing AOXs: Critical Issues in Analytical Methods and Assessment of Possible Inhibitory Effects on Mesophilic and Thermophilic Aerobic Biomasses

This paper offers an in-depth review of adsorbable organic halogens (AOXs), a group of halogenated organic compounds that can be adsorbed from water onto activated carbon. AOXs are emerging contaminants derived from various industrial and household products containing active halogens. Significant concentrations of AOXs are commonly detected in wastewater originating from industries such as the paper and pulp, textile, tannery, chemical and pharmaceutical industries. The standard method for AOX determination is defined in UNI EN ISO 9562:2004. The technical literature indicates that the reliability of AOX measurements can be affected by various factors. This study investigated the possible toxicity of AOXs on wastewater treatment plants, an aspect that has received limited attention in terms of its impact on aerobic biological processes. To bridge this gap, respiratory tests were performed on different aerobic biomasses sourced from large-scale wastewater treatment facilities to evaluate potential inhibitory effects. The results underscore the importance of adopting a case-by-case approach when assessing the risks associated with these contaminants.