Our selection of water reuse publications – December 2019
Research on water reuse: WRE’s pick of recent open access publications – December 2019
Want to keep up to date on the latest research on water reuse? Please find here our selection of open-access articles published recently in Science of the Total Environment, Environment International, Membranes and Water.
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Our selection of open access publications on water reuse – December 2019
Technologies for water reuse
Title: Microbial assisted phytodepuration for water reclamation: Environmental benefits and threats
Authors: Riva, V., Riva, F., Vergani, L., Crotti, E., Borin, S., Mapelli, F.
In: Chemosphere.
Publisher: Elsevier.
Abstract:
Climate changes push for water reuse as a priority to counteract water scarcity and minimize water footprint especially in agriculture, one of the highest water consuming human activities. Phytodepuration is indicated as a promising technology for water reclamation, also in the light of its economic and ecological sustainability, and the use of specific bacterial inocula for microbial assisted phytodepuration has been proposed as a further advance for its implementation. Here we provided an overview on the selection and use of plant growth promoting bacteria in Constructed Wetland (CW) systems, showing their advantages in terms of plant growth support and pollutant degradation abilities. Moreover, CWs are also proposed for the removal of emerging organic pollutants like antibiotics from urban wastewaters. We focused on this issue, still debated in the literature, revealing the necessity to deepen the knowledge on the antibiotic resistance spread into the environment in relation to treated wastewater release and reuse. In addition, given the presence in the plant system of microhabitats (e.g. rhizosphere) that are hot spot for Horizontal Gene Transfer, we highlighted the importance of gene exchange to understand if these events can promote the diffusion of antibiotic resistance genes and antibiotic resistant bacteria, possibly entering in the food production chain when treated wastewater is used for irrigation. Ideally, this new knowledge will lead to improve the design of phytodepuration systems to maximize the quality and safety of the treated effluents in compliance with the ‘One Health’ concept.
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Title: Viral Surrogates in Potable Reuse Applications: Evaluation of a Membrane Bioreactor and Full Advanced Treatment
Authors: Papp, K., Moser, D., Gerrity, D.
In: Journal of Environmental Engineering (United States).
Publisher: American Society of Civil Engineers (ASCE).
Abstract:
This study employed quantitative polymerase chain reaction (qPCR) to evaluate the occurrence and removal of five microbial surrogates at two water reuse facilities. The surrogates were (1) the 16S rRNA gene; (2) the AllBac assay for Bacteroides; (3) the Bacteroides bacteriophage φB124-14; (4) the Bacteroides bacteriophage φcrAssphage; and (5) the pepper mild mottle virus (PMMoV). Log removal values (LRVs) were quantified for a membrane bioreactor (MBR) and across a full advanced treatment (FAT) train. PMMoV, φB124-14, and φcrAssphage were detected in the MBR feed at concentrations of approximately 103 gene• copies(gc)/mL, 105 gc/mL, and 106 gc/mL, respectively. Only PMMoV was above the limit of quantification (LoQ) in the MBR filtrate (25±8 gc/mL), resulting in a wide range of viral LRVs: 1.4±0.5 for PMMoV, >3.9±0.3 for φB124-14, and >6.2±0.3 for φcrAssphage. All molecular targets were above the LoQ in the biologically treated FAT feed, but only the bacterial 16S rRNA gene was >LoQ after ozonation and biological activated carbon (BAC) and in the reverse osmosis (RO) concentrate. The gene was <LoQ in the RO permeate and after the UV advanced oxidation process (AOP).
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Life cycle assessment of water reuse options
Title: Life cycle assessment of decentralized greywater treatment systems with reuse at different scales in cold regions
Authors: Kobayashi, Y., Ashbolt, N.J., Davies, E.G.R., Liu, Y.
In: Environment International
Publisher: Elsevier
Abstract:
Decentralized source-separated wastewater treatment systems offer an attractive alternative to conventional centralized wastewater treatment systems in various regions, yet few system analyses specifically address decentralized greywater treatment over different scales. Here we present a comparative life cycle assessment (LCA) and focus on global warming potential (GWP), eutrophication potential (EUP) and human health – carcinogenic potential (HHCP) of decentralized greywater management systems at different scales for a hypothetical community in a cold (winter) region. To provide a comparison between nature-based and engineered greywater treatment solutions, constructed wetlands (CW) and membrane bioreactors (MBR), respectively, were investigated at three different scales; community (3500 person equivalent [PE]), neighborhood (350 PE) and household (a single household [up to 5 PE]). Conventional centralized wastewater treatment was also included as a business-as-usual (BAU) scenario. In the MBR scenarios, greywater reuse was also considered for multiple non-potable applications due to its high-quality effluent and subsurface garden irrigation was considered for reuse in the CW scenarios. For scenarios with the same treatment technology, larger scales reduced GWP, EUP and HHCP up to 57 kg CO2-eq.PE−1.y−1, 0.2 kg N-eq.PE−1.y−1 and 5.3E-6 CTUh.PE−1.y−1, respectively, despite the need for more extensive wastewater networks. The CW scenarios at community and neighborhood scales outperformed the MBR and BAU scenarios for greywater treatment, while the community-scale MBR scenario may be environmentally preferable when large amount of greywater can be reused. The scale of decentralized systems, quantity of water reused and mix of electricity technologies all played important roles in determining GWP, EUP and HHCP values.
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Title: Characterization of implementation limits and identification of optimization strategies for sustainable water resource recovery through life cycle impact analysis
Authors: Pan, Y.-R., Wang, X., Ren, Z.J., Hu, C., Liu, J., Butler, D.
In: Environment International
Publisher: Elsevier
Abstract:
How we manage alternative freshwater resources to close the gap between water supply and demand is pivotal to the future of the environment and human well-being. Increased scarcity of water for agricultural irrigation in semi-arid and arid regions has resulted in a growing interest in water reuse practices. However, insight into the life cycle impacts and potential trade-offs of these emerging practices are still limited by the paucity of systematic evaluations of different water reuse implementations. In this study, a host of environmental and human health impacts at three implementation levels of allowing water reclamation for crop irrigation was comparatively evaluated across the operational landscape via a combination of scenario modelling, life-cycle impact analyses and Monte Carlo simulations. Net harvesting of reclaimed water for irrigation was found to be dependent upon the sophistication of the treatment processes, since multistage and complex configurations can cause greater direct water consumption during processing. Further, the direct benefits of water resource recovery can be essentially offset by indirect adverse impacts, such as mineral depletion, global warming, ozone depletion, ecotoxicity, and human health risks, which are associated with increased usage of energy and chemicals for rigorous removal of contaminants, such as heavy metals and contaminants of emerging concern. Nonetheless, expanded simulations suggest the significance of concurrently implementing energy recovery, nutrient recycling, and/or nature-based, chemical-free water technologies to reduce the magnitude of negative impacts from engineered water reclamation processes.
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Impact of spatial planning on alternative water supply
Title: Modelling the future impacts of urban spatial planning on the viability of alternative water supply
Authors: Hargreaves, A.J., Farmani, R., Ward, S., Butler, D.
In: Water Research
Publisher: Elsevier
Abstract:
Greywater recycling and rainwater harvesting have the potential to increase the resilience of water management and reduce the need for investment in conventional water supply schemes. However, their water-savings would partly depend on the location and built-form of urban development and hence its household sizes and rainwater per dwelling. We have therefore tested how spatial planning options would affect the future viability of alternative water supply in the Greater South East of England. Our integrated modelling framework, for the first time, forecasts the future densities and variability of built-form to provide inputs to the modelling of alternative water supply. We show that using projections of the existing housing stock would have been unsound, and that using standard dwelling types and household sizes would have substantially overestimated the water-savings, by not fully representing how the variability in dwelling dimensions and household-sizes would affect the cost effectiveness of these systems. We compare the spatial planning trend over a 30 year period with either compaction at higher densities within existing urban boundaries, or market-led more dispersed development. We show how the viability of alternative water supply would differ between these three spatial planning options. The water-savings of rainwater harvesting would vary greatly at a regional scale depending on residential densities and rainfall. Greywater recycling would be less affected by spatial planning but would have a finer balance between system costs and water-savings and its feasibility would vary locally depending on household sizes and water efficiency. The sensitivity of the water savings to differences in rainfall and water prices would vary with residential density. The findings suggest that forecasts of residential densities, rainfall and the water price could be used in conjunction with more detailed local studies to indicate how spatial planning would affect the future water saving potential of alternative water supply.
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