With the neo-metamorphosis of the residential landscape worldwide and sluggish sanitation strategies in urban environments, rudimentary on-site sanitation systems remain commonly used, especially in ...developing countries, despite the risks of groundwater contamination. The effective management of such water resources relies on assessment of the sensitivity of anthropized aquifers to man-made impact, including groundwater behavioural alteration, in terms of both quality and quantity. Associated with tracking of changes in land use, this study proposes an approach involving emerging organic contaminants (EOCs) as indicators of the alteration of groundwater balance due the exposure of shallow aquifers to the risks of infiltration of untreated wastewater from soak pits. This methodology was applied to the shallow aquifer beneath the urban agglomeration of Grand-Sfax (Tunisia). Combined with an updated follow-up of groundwater piezometric fluctuations in relation with inputs from surface contamination sources, the spatialisation of contamination levels by EOCs provided a clear delineation of the most impacted aquifer zones. This approach revealed a significant link between the continuous rise in piezometric levels by contributions from untreated inputs and the accumulation of high levels of contamination in groundwater. The understanding of EOC underground pathways allowed the determination of the fates and processes responsible for the diffusion of contamination throughout the studied aquifer. The ability of groundwater to reflect population life style and the use patterns of such organic molecules was also assessed. Besides revealing the legacy of persistent contamination, this approach involving EOCs as tracers with different levels of persistence provided a spatial observation of the aquifer exposure to continuous contamination processes. This approach made it possible to develop a conceptual presentation of aquifer vulnerability to urban pressures and to predict the effects of subsequent expansion of unplanned urbanisation on groundwater quality.
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•Assessment of aquifer vulnerability to unplanned urban expansion and poor sanitation•Increasing groundwater level due to untreated wastewater infiltration from soak pits•Clear relationship between the piezometric rise and contaminants accumulation•Highlighting the issues of the legacy of persistent contamination in groundwater•Groundwater contamination reflects the use patterns of EOCs by population
Globally, there is increasing interest in recovering resources from sanitation systems. However, the process of planning and implementing circular sanitation is complex and can necessitate ...software-based tools to support decision-making. In this paper, we review 24 decision support software tools used for sanitation planning, to generate insights into how they address resource recovery across the sanitation chain. The findings reveal that the tools can address many planning issues around resource recovery in sanitation including analysis of material flows, integrating resource recovery technologies and products in the design of sanitation systems, and assessing the sustainability implications of resource recovery. The results and recommendations presented here can guide users in the choice of different tools depending on, for example, what kind of tool features and functions the user is interested in as well as the elements of the planning process and the sanitation service chain that are in focus. However, some issues are not adequately covered and need improvements in the available tools including quantifying the demand for and value of resource recovery products, addressing retrofitting of existing sanitation infrastructure for resource recovery and assessing social impacts of resource recovery from a life cycle perspective. While there is scope to develop new tools or to modify existing ones to cover these gaps, communication efforts are needed to create awareness about existing tools, their functions and how they address resource recovery. It is also important to further integrate the available tools into infrastructure planning and programming processes by e.g. customizing to relevant planning regimes and procedures, to move them beyond research and pilots into practice, and hopefully contribute towards more circular sanitation systems.
•We review 24 decision support software tools used for sanitation planning.•We characterize how they address resource recovery aspects.•Several tools analyse material flows and integrate resource recovery technologies and products in sanitation system design .•Many tools have features to assess sustainability aspects of resource recovery.•Recommendations are made for which tools best address each aspect of resource recovery planning.
The plant nutrients consumed in human society today are lost through the established wastewater treatment systems in industrialised countries as well as via insufficient or non-existent handling of ...sewage in the developing world. New sanitation systems have been designated to overcome this failure. The source separated wastewater streams collected within these systems contain a high nutrient content, and can be used as fertiliser as well as soil conditioner after appropriate storage and/or treatment. Application in agriculture with existing techniques is feasible. However, pathogens and pharmaceuticals contained in these fertiliser types are a potential hazard. Nevertheless, storage and appropriate treatment can minimise the risks. The products deriving from these systems have a high potential to preserve available plant nutrient resources and deficiencies in agriculture as well as being able to substitute synthetic plant nutrients and at the same time prevent unwanted environmental nutrient over-enrichment.
Current methods for estimating sanitation emissions underestimate the significance of methane emissions from non-sewered sanitation systems (NSSS), which are prevalent in many countries. NSSS play a ...vital role in the safe management of fecal sludge, accounting for approximately half of all existing sanitation provisions. We analyzed the distribution of global NSSS and used IPCC accounting methods to estimate the total methane emissions profiles from these systems. Then, we examined the literature to establish the level of uncertainty associated with this accounting estimate. The global methane emissions from NSSS in 2020 was estimated to as 377 (22–1003) Mt CO2e/year or 4.7% (0.3%–12.5%) of global anthropogenic methane emissions, which are comparable to the greenhouse gas (GHG) emissions from wastewater treatment plants. NSSS is the major option for open defecation and is expected to increase by 55 Mt CO2e/year after complete open defecation free. It is time to acknowledge the GHG emissions from the NSSS as a non-negligible source.
•The global distribution of NSSS was partially visualized.•The CH4 emission from global NSSS was tentatively calculated.•The impact of temperature on the in-situ monitoring was briefly analyzed.•The carbon emissions from NSSS and WWTPs were generally compared.
The United Nations’ Sustainable Development Goals (SDGs) recognize that current sanitation gaps must be closed to better serve those without access to safely managed systems (Target 6.2: universal ...sanitation coverage) and those connected to sewers without wastewater treatment (Target 6.3: halving the proportion of untreated wastewater). Beyond mitigating environmental and health concerns, implementing resource recovery sanitation systems could simultaneously improve the availability of agricultural nutrients (SDG 2) and household energy (SDG 7). This study estimates the potential for global, regional, and country-level resource recovery to impact nutrient and household electricity use through 2030. We distinguish impacts from newly installed sanitation systems (to achieve universal coverage), newly treated wastewater systems (to halve the proportion of untreated wastewater), and existing system replacement, while also considering urban and rural disparities and spatial colocation of nutrients with agricultural needs. This work points toward country-specific strategies for deriving the greatest benefit from sanitation investments while also identifying overarching trends to guide international research efforts. Globally, potential nutrient gains are an order of magnitude larger than electricity (a small fraction of total energy), and considerable impacts are possible in the least-developed countries, six of which could double or offset all projected nutrient and electricity use through newly installed sanitation systems.
To address one of the most severe global challenges affecting human health and the environment, two new voluntary product standards (ISO 30500 and ISO 31800) for nonsewered sanitation systems (NSSS) ...and fecal sludge treatment units (FSTUs) have been developed and published. While providing stringent voluntary product requirements for the containment and the treatment of human excreta with safe outputs (air, liquids, and solids), ISO 30500 and ISO 31800 make the inextricable connections between environmental emission thresholds, technical innovations, and sustainability aspects of NSSS and FSTUs. The purpose of this feature is to discuss these connections.
Abstract
Background
Wastewater-based epidemiology (WBE) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can be an important source of information for coronavirus disease 2019 ...(COVID-19) management during and after the pandemic. Currently, governments and transportation industries around the world are developing strategies to minimize SARS-CoV-2 transmission associated with resuming activity. This study investigated the possible use of SARS-CoV-2 RNA wastewater surveillance from airline and cruise ship sanitation systems and its potential use as a COVID-19 public health management tool.
Methods
Aircraft and cruise ship wastewater samples (n = 21) were tested for SARS-CoV-2 using two virus concentration methods, adsorption–extraction by electronegative membrane (n = 13) and ultrafiltration by Amicon (n = 8), and five assays using reverse-transcription quantitative polymerase chain reaction (RT-qPCR) and RT-droplet digital PCR (RT-ddPCR). Representative qPCR amplicons from positive samples were sequenced to confirm assay specificity.
Results
SARS-CoV-2 RNA was detected in samples from both aircraft and cruise ship wastewater; however concentrations were near the assay limit of detection. The analysis of multiple replicate samples and use of multiple RT-qPCR and/or RT-ddPCR assays increased detection sensitivity and minimized false-negative results. Representative qPCR amplicons were confirmed for the correct PCR product by sequencing. However, differences in sensitivity were observed among molecular assays and concentration methods.
Conclusions
The study indicates that surveillance of wastewater from large transport vessels with their own sanitation systems has potential as a complementary data source to prioritize clinical testing and contact tracing among disembarking passengers. Importantly, sampling methods and molecular assays must be further optimized to maximize detection sensitivity. The potential for false negatives by both wastewater testing and clinical swab testing suggests that the two strategies could be employed together to maximize the probability of detecting SARS-CoV-2 infections amongst passengers.
New and alternative sanitation systems are increasingly discussed and find their way into implementation. However, discussions on sanitation concepts often are held in a rather emotional way. ...Furthermore, not all the available sanitation concepts might be known to the decision maker. The work presented here attempts to contribute to a good discussion and decision making process by compiling available technologies, by defining easy-to-implement criteria for a sustainability assessment method and by integrating these results into a simulation tool which allows to visualize the related resource fluxes (e.g. those on nutrients, such as N, P and K) and to analyse different sanitation options with regard to their capital and operational costs and with regard to environmental impact criteria such as greenhouse gas emissions. Whilst the calculations are to be considered as being approximate in their nature (due to uncertainties or lack of suitable input data), this tool allows the planners, with sometimes little modelling experience, to consider the characteristics of sanitation systems. Whilst starting from earlier work, such as Eawag's Sanitation Compendium and work on material flow analysis, work described in this contribution merges resource flux modelling, easy-to-use simulation and visualization and methods of life cycle assessment and life cycle costing. The simulation tool is freely available on https://www.ifak.eu/en/products/sampsons.
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