Our selection of open access publications on water reuse – April 2020
You will find below our selection of open-access articles published this quarter on regulations, public perception and acceptance of water reuse, emerging contaminants in agricultural reuse and membrane technologies for water reuse published in Environmental Sciences Europe, Safety Science, Journal of Environment Management, Environment International, Science of the Total Environment and Journal of Membrane Science.
Regulations
Title: Regulating water reuse for agricultural irrigation: risks related to organic micro-contaminants
Authors: Helmecke, M., Fries, E. and Schulte, C.
In: Environmental Sciences Europe
Publisher: SpringerOpen
Abstract:
In recent years, more and more countries see irrigation using reclaimed water as an opportunity to secure and enhance agricultural production. Despite the benefits of water reuse, the scientific community raised several concerns and challenges for human health and the environment. This includes chemical risks. Effluents from urban wastewater treatment plants usually contain a wide range of organic chemicals. Such chemicals remaining in the water after the treatment process may cause hazards for human health, contaminate surrounding soil and water resources, and even compromise drinking water sources. Once crops on irrigated sites are exposed to chemicals, the potential transport to and accumulation in the edible parts of fruits and vegetables need to be controlled to rule out their introduction into the food chain. Finally, problems concerning the release of wastewater-borne antibiotics into the environment are starting to gain attention. For these reasons, agricultural irrigation should face more stringent quality requirements in order to minimize chemical risks. Combinations of measures reducing chemicals at the source, technical and natural water treatment processes especially to remove chemicals with persistent, bioaccumulative and toxic (PBT), or persistent, mobile and toxic (PMT) properties, good agricultural practices, and supplementary preventive measures (e.g. knowledge transfer to the stakeholders involved) will be necessary to bring about and ensure safe irrigation in the future. While internationally many regulations and guidelines for water reuse have successfully been implemented, questions remain whether the current knowledge regarding chemical risks is sufficiently considered in the regulatory context. The introduction of a new regulation for water reuse, as attempted in the European Union, poses a good opportunity to better take chemicals risks into account.
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Title: Making water reuse safe: A comparative analysis of the development of regulation and technology uptake in the US and Australia
Authors: Mukherjee, M. and Jensen, O.
In: Safety Science
Publisher: Elsevier – ScienceDirect
Abstract:
Highly treated wastewater supplied for potable or non-potable purposes, or ‘water reuse,’ is a promising additional source of supply in water-scarce areas. However, the adoption of water reuse has been constrained by a lack of public acceptance of the technology, in particular for potable use. The development of regulatory frameworks for reuse may help to address safety concerns and support adoption. This paper investigates the interaction between regulation, public acceptance and technology adoption for potable reuse. It employs a Process Tracing methodology to analyse two country cases, the US and Australia, both of which have experience in successful adoption of potable reuse as well as examples of public resistance and abandonment of specific projects. The cases suggest that local, collaborative, transparent risk-based regulation contributes to increased acceptance of reuse among the public and government officials and supports take-up of the technology.
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Public perception and acceptance of water reuse
Title: Recycled or reclaimed? The effect of terminology on water reuse perceptions
Authors: McClaran, N., Behe, B.K., Huddleston, P and Thomas Fernandez, R.
In: Journal of Environment Management
Publisher: Elsevier
Abstract:
Successful water recycling initiatives depend on public acceptance. In this study, we compared risk perceptions of water labelled as recycled or reclaimed. We recruited 1264 subjects in an online panel (Qualtrics) and randomly assigned them either treatment (recycled or reclaimed) water and asked about the contents and perceived risk. Participants in the reclaimed condition were more likely to perceive the water to have harmful ingredients compared to the recycled condition. The odds of direct use acceptance for those in the recycled condition are 1.41 times (or 41%) more likely than those in the reclaimed condition. Similar results were found for indirect uses. A major finding of this study is that terminology influences the perceived contaminants and risk of reused water. Prior studies have found strong evidence that the way reused water is communicated can influence public perception. Policy implications favour the use of recycled water, likely due to the positive connotation recycling has in the U.S. today.
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Title: Can conformity overcome the yuck factor? Explaining the choice for recycled drinking water
Authors: Leong, C and and Lebel, L
In: Journal of Cleaner Production
Publisher: Science Direct
Abstract:
Of the 17 SDGS, the United Nations has recently revealed that countries are not on track to receive the water and sanitation goals by the deadline. As climatic events decrease the reliability of traditional drinking sources, especially in cities, recycled drinking water (RDW) is becoming an increasingly important policy option. Yet, the implementation of RDW remains mired in difficulties, with the psychological “yuck” factor as a key obstacle. Studies of successful cases of RDW implementation show that trust, information and social norms are important. However, no studies of RDW have directly compared the relative importance of information to the power of social norms. This paper explores the role of conformity, as a social norm, in increasing public acceptance of recycled water for drinking. Using a simple choice experiment, we find that conformity per se appears to provide sufficient reason for behavioural change relating to recycled water, rather than information or economic incentives. This study is one of the first to present empirical evidence from a choice experiment on RDW, and has practical implications on the use of conformity as motivation to taking difficult decisions.
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Emerging contaminants in agricultural reuse
Title: Evaluation of chemical and biological contaminants of emerging concern in treated wastewater intended for agricultural reuse
Authors: Alygizakis, N.A., Urík, J., Beretsou, V.G., Kampouris, I., Galani, A., Oswaldova, M., Berendonk, T., Oswald, P., Thomaidis, N.S., Slobodnik, J., Vrana, B. and Fatta-Kassinos, D.
In: Environment International
Publisher: Elsevier – ScienceDirect
Abstract:
The occurrence of chemical and biological contaminants of emerging concern (CECs) was investigated in treated wastewater intended for reuse in agriculture. An agarose hydrogel diffusion-based passive sampler was exposed to the outlet of a wastewater treatment plant (WWTP) located in Cyprus, which is equipped with membrane bioreactor (MBR). Passive samplers in triplicate were exposed according to a time-series exposure plan with maximum exposure duration of 28 days. Composite flow-proportional wastewater samples were collected in parallel with the passive sampling exposure plan and were processed by solid phase extraction using HORIZON SPE-DEX 4790 and the same sorbent material (Oasis HLB) as in the passive sampler. The analysis of passive samplers and wastewater samples enabled (i) the field-scale calibration of the passive sampler prototype by the calculation of in situ sampling rates of target substances, and (ii) the investigation of in silico predicted transformation products of the four most ecotoxicologically hazardous antibiotics (azithromycin, clarithromycin, erythromycin, ofloxacin). Additionally, the wastewater samples were subjected to the analysis of seven preselected antibiotic resistant genes (ARGs) and one mobile resistant element (int1). All extracts were analyzed for chemicals in a single batch using a highly sensitive method for pharmaceuticals, antibiotics and illicit drugs by liquid chromatography tandem MS/MS (LC-QQQ) and for various other target compounds (2316 compounds in total) by liquid chromatography high-resolution mass spectrometry (LC-HRMS). 279 CECs and all investigated ARGs (except for blaCTX-M−32) were detected, highlighting potential chemical and biological hazards related to wastewater reuse practices. 16 CECs were prioritized following ecotoxicological risk assessment, whereas sul1 and the mobile resistant element (int1) showed the highest abundance. Comprehensive monitoring efforts using novel sampling methods such as passive sampling, wide-scope target screening and molecular analysis are required to assure safe application of wastewater reuse and avoid spread and crop uptake of potentially hazardous chemicals.
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Title: Pharmaceuticals and trace metals in the surface water used for crop irrigation: Risk to health or natural attenuation?
Authors: de Santiago-Martín, A., Meffe, R., Teijón, G., Martínez Hernández, V., López-Heras, I., Alonso Alonso, C., Arenas Romasanta, M., de Bustamante, I.
In: Science of the Total Environment
Publisher: Elsevier – ScienceDirect
Abstract:
The use of surface water impacted by wastewater treatment plant (WWTP) effluents for crop irrigation is a form of unplanned water reuse. Natural attenuation processes can buffer contamination spreading. However, this practice can promote the exposure of crops to contaminants of emerging concern, such as pharmaceuticals, trace metals (TMs) and metalloids, posing a risk to health. This research aimed to evaluate the presence of 50 pharmaceuticals, some transformation products, 7 TMs and a metalloid in the water-sediment-soil-plant system, and their potential to be bioaccumulated into edible parts of plants, as a result of the unplanned water reuse. The study site consists of an extensive agricultural land downstream Madrid city (Spain) where surface water, strongly impacted by WWTP effluents, is applied through gravity-based systems to cultivate mainly maize. Sampling campaigns were conducted to collect WWTP effluent, surface and irrigation water, river sediments, agricultural soils and maize fruits. Results demonstrate the ubiquitous presence of several pharmaceuticals. The concentration pattern in irrigation water did not resemble the pattern of contents in soils and plants. The pharmaceuticals included in the EU surface water watch lists were quantified in the lowest concentration range (macrolide antibiotics, ciprofloxacin) or were not detected (most of the hormones). Therefore, hormones do not represent an emerging risk in our scenario. The TMs and the metalloid in water and agricultural soils should not arise any concern. Whereas, their presence in the river sediments may have an adverse impact on aquatic ecosystems. Only acetaminophen, ibuprofen, carbamazepine, nicotine, Zn, Cu and Ni were quantified in corn grains. Calculated parameters to assess bioaccumulation and health risk indicate that neither pharmaceuticals nor TMs pose a threat to human health due to consumption of maize cultivated in the area. Results highlight the need to include different environmental matrices when assessing contaminant fate under real field-scale conditions.
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Membrane technologies for water reuse
Title: Fouling substances causing variable rejection of a small and uncharged trace organic chemical by reverse osmosis membranes
Authors: Fujioka, T., Aizawa, H., Kodamatani, H.
In: Environmental Technology and Innovation
Publisher: Elsevier – ScienceDirect
Abstract:
The safety of recycled water for potable water reuse can be enhanced by improving the reliability of reverse osmosis (RO) treatment for the removal of trace organic chemicals. This study assessed the mechanisms underlying the variable rejection of a carcinogenic N-nitrosamine, namely N-nitrosodimethylamine (NDMA), caused by RO membrane fouling. Foulants that cause the variable rejection were evaluated through rejection tests and foulant characterization. The RO treatment of wastewaters with and without pre-treatment using an ultrafiltration or nanofiltration membrane showed that NDMA rejection commonly increased with increasing membrane fouling. The characterization of organics in the treated wastewater samples revealed that increased NDMA rejection can be caused by foulants composed of low-molecular-weight organics (<300 Da), including tryptophan (or tryptophan-like substances). It is speculated that small organics such as tryptophan form a densely packed cake layer on the membrane surface, which may function as an additional barrier for the membrane transport of NDMA. The results of this study indicate that RO membrane fouling that occurs during long-term wastewater treatment can increase NDMA rejection. The enhanced separation performance can yield positive consequences for the credibility of RO treatment in potable water reuse.
Article available here.
Title: Combined membrane filtration and 265 nm UV irradiation for effective removal of cell free antibiotic resistance genes from feed water and concentrate.
Authors: Krzeminski, P., Feys, E., Anglès d’Auriac, M., Wennberg, A.C., Umar, M., Schwermer, C.U., Uhl, W.
In: Journal of Membrane Science
Publisher: Elsevier – ScienceDirect
Abstract:
The removal of cell free DNA (plasmids) carrying antibiotic resistance genes (ARGs) was investigated at bench-scale using ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) membranes commonly applied in water reuse applications. The removal of the plasmid spiked to ultrapure water was determined using a direct qPCR method. More than 99% plasmid removal was achieved by membranes with 1 kDa molecular weight cut off (MWCO). Membranes with lower MWCO showed complete removal under the specific experimental conditions, reaching a maximum log reduction value above 6.6. The concentrate from membrane filtration was further subjected to UV-LED irradiation at 265 nm. The required fluence for 1 log damage was 73 mJ/cm2 for the 267 target bp segment and 23 mJ/cm2 for the 601 target bp segment, respectively. With these two DNA segments, the inactivation rate per segment length was higher for the larger segment, in accordance with a higher pyrimidine and TT content, compared with the smaller fragment. Target DNA was not detectable anymore when using 100 and 300 mJ/cm2 for the 601 and 267 bp segments respectively. The results indicate that membrane filtration, combined with UV-LED treatment of the concentrate, can be an effective measure to remove and inactivate ARGs from water to prevent their release to the environment.
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