Development of a qualitative approach to assessing risks associated with the use of treated wastewater in agricultural irrigation

The European Commission’s draft regulation for minimum requirements for water reuse in agriculture addresses microbial and basic water quality parameters but does not consider the potential impacts of chemicals of emerging concern (CECs) on human and environmental health. Because insufficient data prevents the quantitative characterisation of risks posed by CECs in treated wastewater (TWW), this paper presents a framework, which combines data and expert judgement to assess likelihood of occurrence and magnitude of impact. An increasing relative scale is applied where numeric values are pre-defined to represent comparative levels of importance. Subsequently, an overall assessment of the level of risk is characterised by multiplying together allocated scores, to obtain a single discrete overall score per CEC. Guidelines to support implementation of the framework as far as soil (the initial receiving compartment and pathway to further protected targets) are developed and applied. The approach is demonstrated through its application to clarithromycin, where results indicate that – under the considered scenario - there is limited possibility of its occurrence in soil in a bioavailable form. The role of a qualitative risk assessment approach is considered and the opportunity for its outputs to inform future research agendas described

Recommendations to derive quality standards for chemical pollutants in reclaimed water intended for reuse in agricultural irrigation

The reuse of treated municipal wastewater (herein referred to as reclaimed water) in agricultural irrigation (RWAI) as a means to alleviate water scarcity is gaining increasing policy attention, particularly in areas where water demand mitigation measures have proved insufficient. However, reclaimed water reuse in practice is lagging behind policy ambition, with <2.5% of it reused in a European context. A key barrier identified as limiting its full valorisation is concern over its impact on human and environmental health. To address this concern, and to meet further objectives including achieving parity between current reclaimed water reuse guidelines operational in various Member States, the European Commission has proposed a regulation which identifies minimum quality requirements (MQR) for a range of microbiological and physico-chemical parameters but the inclusion of compounds of emerging concern (CECs) in terms of the determination of quality standards (QS) is missing. This paper reviews the existing pertinent EU legislation in terms of identifying the need for CEC QS for RWAI, considering the scope and remit of on-going pan-European chemicals prioritisation schemes. It also evaluates opportunities to link in with the existing EQS derivation methodology under the EU WFD to address all protection targets in the environmental compartments exposed via potential pathways of RWAI. Finally, it identifies the main data gaps and research needs for terrestrial ecosystems, the removal efficiency of CECs by WWTPs and transformation products generated during the wastewater reuse cycle

Nireas, International Water Research Center (Nireas-IWRC) of the University of Cyprus

The Nireas International Water Research Center (Nireas-IWRC) was established in 2011 with the vision of reaching out to the wider scientific community to exchange knowledge and best practices, to advance the state-of-the-art in water-related scientific research and technologies, and to strengthen public awareness on waterrelated issues. The Center’s mission is twofold: to conduct research of high international caliber, while at the same time serving the research needs of Cypriot society, economy, and industry. Among the Center’s many research, social, and dissemination activities, of particular note are its efforts in the thematic research areas of: (i) Water Quality, Monitoring and Treatment; (ii) Water Supply and Urban Water Management; and (iii) Socioeconomic Analysis of Water-Related Issues. Nireas-IWRC researchers have already secured significant national, EU, and international funding, and their research results have widely been disseminated in peer-reviewed journals, international conferences, technical reports, and technical workshops.[Contrib Sci 10:221-228 (2014)

Can solar water-treatment really help in the fight against water shortages?

In the face of increasing global population, rising industrialization and the inescapable reality of climate change, the demand for access to clean, safe water has never been greater. Solar wastewater remediation technologies and solar water-treatment have the potential to contribute significantly towards affordable and sustainable solutions to this seemingly intractable problem. They do this by using solar energy to treat water from sources that previously would have been considered unsuitable for further use. In this article we reveal the basic principles surrounding the design and application of solar remediation reactors for urban wastewater treatment and reuse and then show how even simpler technologies are being used in low-income communities to provide affordable and safe potable water

Antibiotic resistance in urban aquatic environments: can it be controlled?

Over the last decade, numerous evidences have contributed to establish a link between the natural and human-impacted environments and the growing public health threat that is the antimicrobial resistance. In the environment, in particular in areas subjected to strong anthropogenic pressures, water plays a major role on the transformation and transport of contaminants including antibiotic residues, antibiotic-resistant bacteria, and antibiotic resistance genes. Therefore, the urban water cycle, comprising water abstraction, disinfection, and distribution for human consumption, and the collection, treatment, and delivery of wastewater to the environment, is a particularly interesting loop to track the fate of antibiotic resistance in the environment and to assess the risks of its transmission back to humans. In this article, the relevance of different transepts of the urban water cycle on the potential enrichment and spread of antibiotic resistance is reviewed. According to this analysis, some gaps of knowledge, research needs, and control measures are suggested. The critical rationale behind the measures suggested and the desirable involvement of some key action players is also discussed.info:eu-repo/semantics/acceptedVersio

Examining the Relevance of the Microplastic-Associated Additive Fraction in Environmental Compartments

Plastic contamination is ubiquitous in the environment and has been related to increasing global plastic usage since the 1950s. Considering the omnipresence of additives in plastics, the risk posed by this contamination is related not only to the physical effects of plastic particles but also to their additive content. Until now, most routine environmental monitoring programs involving additives have not considered the presence of these additives still associated with the plastic they were added to during their production. Understanding environmental additive speciation is essential to address the risk they pose through their bioavailability and plastic-associated transport. Here, we present and apply a theoretical framework for sampling and analytical procedures to characterize the speciation of hydrophobic nonionized additives in environmental compartments. We show that this simple framework can help develop sampling and sample treatment procedures to quantify plastic-associated additives and understand additive distribution between plastics and organic matter. When applied to concrete cases, internal consistency checks with the model allowed for identifying plastic-associated additives in a sample. In other cases, the plastic-organic carbon ratio and additive concentration in the matrix are key factors affecting the ability to identify plastic-associated additives. The effect of additive dissipation through diffusion out of plastic particles is also considered.publishedVersio

Investigation of the effect of microplastics on the UV inactivation of antibiotic-resistant bacteria in water

This study investigated the effect of polyethylene and polyvinyl chloride microplastics on the UV fluence response curve for the inactivation of multidrug-resistant E. coli and enterococci in ultrapure water at pH 6.0 ± 0.1. In the absence of microplastics, the UV inactivation of the studied bacteria exhibited an initial resistance followed by a faster inactivation of free (dispersed) bacteria, while in the presence of microplastics, these 2 regimes were followed by an additional regime of slower or no inactivation related to microplastic-associated bacteria (i.e., bacteria aggregated with microplastics resulting in shielding bacteria from UV indicated by tailing at higher UV fluences). The magnitude of the negative effect of microplastics varied with different microplastics (type/particle size) and bacteria (Gram-negative and Gram-positive). Results showed that when the UV transmittance of the microplastic-containing water was not taken into account in calculating UV fluences, the effect of microplastics as protectors of bacteria was overestimated. A UV fluence-based double-exponential microbial inactivation model accounting for both free and microplastic-associated bacteria could describe well the disinfection data. The present study elucidated the effect of microplastics on the performance of UV disinfection, and the approach used herein to prove this concept may guide future research on the investigation of the possible effect of other particles including nanoplastics with different characteristics on the exposure response curve for the inactivation of various microorganisms by physical and chemical disinfection processes in different water and wastewater matrices.publishedVersio

The environmental footprint of a membrane bioreactor treatment process through Life Cycle Analysis

This study includes an environmental analysis of a membrane bioreactor (MBR), the objective being to quantitatively define the inventory of the resources consumed and estimate the emissions produced during its construction, operation and end-of-life deconstruction. The environmental analysis was done by the life cycle assessment (LCA) methodology, in order to establish with a broad perspective and in a rigorous and objective way the environmental footprint and the main environmental hotspots of the examined technology. Raw materials, equipment, transportation, energy use, as well as air- and waterborne emissions were quantified using as a functional unit, 1 m3 of urban wastewater. SimaPro 8.0.3.14 was used as the LCA analysis tool, and two impact assessment methods, i.e. IPCC 2013 version 1.00 and ReCiPe version 1.10, were employed. The main environmental hotspots of the MBR pilot unit were identified to be the following: (i) the energy demand, which is by far the most crucial parameter that affects the sustainability of the whole process, and (ii) the material of the membrane units. Overall, the MBR technology was found to be a sustainable solution for urban wastewater treatment, with the construction phase having a minimal environmental impact, compared to the operational phase. Moreover, several alternative scenarios and areas of potential improvement, such as the diversification of the electricity mix and the material of the membrane units, were examined, in order to minimize as much as possible the overall environmental footprint of this MBR system. It was shown that the energy mix can significantly affect the overall sustainability of the MBR pilot unit (i.e. up to 95% reduction of the total greenhouse gas emissions was achieved with the use of an environmentally friendly energy mix), and the contribution of the construction and operational phase to the overall environmental footprint of the system.This work was funded by Nireas, International Water Research Center of the University of Cyprus (ΝΕΑ ΥΠΟΔΟΜΗ/ΣΤΡΑΤΗ/0308/09), which was co-funded by the European Regional Development Fund and the Republic of Cyprus through the Research Promotion Foundation. The authors are grateful to the manufacturer company of the MBR pilot unit, S.K. Euromarket Ltd., as well as to Ms. Popi Karaolia of Nireas-IWRC of the University of Cyprus, for providing technical information to the study

The potential implications of reclaimed wastewater reuse for irrigation on the agricultural environment: the knowns and unknowns of the fate of antibiotics and antibiotic resistant bacteria and resistance genes – a review

The use of reclaimed wastewater (RWW) for the irrigation of crops may result in the continuous exposure of the agricultural environment to antibiotics, antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs). In recent years, certain evidence indicate that antibiotics and resistance genes may become disseminated in agricultural soils as a result of the amendment with manure and biosolids and irrigation with RWW. Antibiotic residues and other contaminants may undergo sorption/desorption and transformation processes (both biotic and abiotic), and have the potential to affect the soil microbiota. Antibiotics found in the soil pore water (bioavailable fraction) as a result of RWW irrigation may be taken up by crop plants, bioaccumulate within plant tissues and subsequently enter the food webs; potentially resulting in detrimental public health implications. It can be also hypothesized that ARGs can spread among soil and plant-associated bacteria, a fact that may have serious human health implications. The majority of studies dealing with these environmental and social challenges related with the use of RWW for irrigation were conducted under laboratory or using, somehow, controlled conditions. This critical review discusses the state of the art on the fate of antibiotics, ARB and ARGs in agricultural environment where RWW is applied for irrigation. The implications associated with the uptake of antibiotics by plants (uptake mechanisms) and the potential risks to public health are highlighted. Additionally, knowledge gaps as well as challenges and opportunities are addressed, with the aim of boosting future research towards an enhanced understanding of the fate and implications of these contaminants of emerging concern in the agricultural environment. These are key issues in a world where the increasing water scarcity and the continuous appeal of circular economy demand answers for a long-term safe use of RWW for irrigation