COST Action ES1403: new and emerging challenges and opportunities in wastewater REUSe (NEREUS)

Treated urban wastewater is currently widely reused to compensate for dwindling water supplies, as it is considered to be a reliable alternative water source. In addition, the increasing demand for food due to the expanding world population, both in respect to food security and food safety, and therefore for irrigation water, renders wastewater reuse a practice of utmost importance. As a consequence, sustainable and safe urban water cycles are presently of high priority on the policy agendas of many countries around the world. Although reuse has a number of benefits and major advances have been made with respect to producing treated effluents for reuse (e.g., successful removal of metals, reduction of chemical oxygen demand and of other pollution parameters), several important questions are still unanswered and barriers exist regarding the safety/sustainability of reuse practice. Knowledge gaps associated with wastewater reuse include the following: (a) possible elemental interactions that may influence the accumulation of metals/elements in the soil and their subsequent uptake by plants and crops, (b) the fateof organic microcontaminants in receiving environments, and (c) the epidemiological potential of antibiotic resistant bacteria and/or resistance genes (ARB&ARG) released in the environment via treated effluent. Possible implications on food-chain contamination (biomagnification) require much attention, since treated wastewater is not exempt of such contaminants. The effluents’ residual organic matter after conventional treatment consists of a number of recalcitrant organic compounds including potential endocrine disrupting compounds, many types of pharmaceuticals including antibiotics, disinfection by-products, personal care products, metabolites and transformation products, other organic substances (i.e. pesticides, surfactants, biocides, etc.), and not to be forgotten ARB&ARG. In fact, preliminary results suggest that the relative abundance of certain ARG or ARB may even be enriched during the wastewater treatment (Rizzo et al. 2013). This leads to their subsequent release in the terrestrial and aquatic environments through disposal and reuse applications, and the level of risk to environmental and human health is yet to be evaluated. Contamination of the environment, food chain, drinking water, etc with ARB&ARG is presently considered to be a serious public health problem. For this reason, the World Health Organization (WHO) (WHO 2013) characterized the development of AR as one of the major global threats to society and recommends intensive monitoring for the identification/surveillance of critical hot spots (e.g., wastewater treatment plants), aiming at reducing its propagation. In September 2014, a national strategy (The White House 2014) was announced in the USA by the White House that lays out a series of steps to address the decreasing effectiveness of antibiotics, many being similar to those identified by WHO. According to the European Centre for Disease Prevention and Control, it is estimated that infections caused by a subset of ARB are responsible for about 25,000 deaths in Europe annually. In addition, the extra healthcare costs and productivity losses due to ARB are estimated to reach EUR 1.5 billion (European Centre for Disease Prevention and Control 2013). In the USA, equally dramatic numbers are reported by the Centers for Disease Control and Prevention, with AR infections killing at least 23,000 people and sickening 2 million each year (The White House 2014). All these issues have not received significant attention in the framework of the wastewater reuse practice. The EUCOST Action ES1403 (NEREUS) aims at consolidating the existing scattered data related to wastewater reuse and will address the open challenges associated with it. It will provide the platform for a systematic consolidation of data and standardization of methods for assessing emerging hazards associated with wastewater reuse. The Action is chaired by D. Fatta-Kassinos from Nireas-International Water Research Center and Department of Civil and Environmental Engineering of the University of Cyprus and vice-chaired by C.Manaia from Escola Superior de Biotecnologia, Universidade Católica Portugeusa.