Applying a Digital Twin and wastewater analysis for robust validation of COVID-19 pandemic forecasts: insights from Catalonia

Monitoring SARS-CoV-2 spread is challenging due to asymptomatic infections, numerous variants, and population behavior changes from non-pharmaceutical interventions. We developed a Digital Twin model to simulate SARS-CoV-2 evolution in Catalonia. Continuous validation ensures our model's accuracy. Our system uses Catalonia Health Service data to quantify cases, hospitalizations, and healthcare impact. These data may be under-reported due to screening policy changes. To improve our model's reliability, we incorporate data from the Catalan Surveillance Network of SARS-CoV-2 in Sewage (SARSAIGUA). This paper shows how we use sewage data in the Digital Twin validation process to identify discrepancies between model predictions and real-time data. This continuous validation approach enables us to generate long-term forecasts, gain insights into SARS-CoV-2 spread, reassess assumptions, and enhance our understanding of the pandemic's behavior in Catalonia.

Profiling wastewater characteristics in intra-urban catchments using online monitoring stations

This study aims to investigate the differences in intra-urban catchments with different characteristics through real-time wastewater monitoring. Monitoring stations were installed in three neighbourhoods of Barcelona to measure flow, total chemical oxygen demand (COD), pH, conductivity, temperature, and bisulfide (HS-) for 1 year. Typical wastewater profiles were obtained for weekdays, weekends, and holidays in the summer and winter seasons. The results reveal differences in waking up times and evening routines, commuting behaviour during weekends and holidays, and water consumption. The pollutant profiles contribute to a better understanding of pollution generation in households and catchment activities. Flows and COD correlate well at all stations, but there are differences in conductivity and HS- at the station level. The article concludes by discussing the operational experience of the monitoring stations.

Wastewater-based epidemiology applied at the building-level reveals distinct virome profiles based on the age of the contributing individuals

BACKGROUND

Human viruses released into the environment can be detected and characterized in wastewater. The study of wastewater virome offers a consolidated perspective on the circulation of viruses within a population. Because the occurrence and severity of viral infections can vary across a person's lifetime, studying the virome in wastewater samples contributed by various demographic segments can provide valuable insights into the prevalence of viral infections within these segments. In our study, targeted enrichment sequencing was employed to characterize the human virome in wastewater at a building-level scale. This was accomplished through passive sampling of wastewater in schools, university settings, and nursing homes in two cities in Catalonia. Additionally, sewage from a large urban wastewater treatment plant was analysed to serve as a reference for examining the collective excreted human virome.

RESULTS

The virome obtained from influent wastewater treatment plant samples showcased the combined viral presence from individuals of varying ages, with astroviruses and human bocaviruses being the most prevalent, followed by human adenoviruses, polyomaviruses, and papillomaviruses. Significant variations in the viral profiles were observed among the different types of buildings studied. Mamastrovirus 1 was predominant in school samples, salivirus and human polyomaviruses JC and BK in the university settings while nursing homes showed a more balanced distribution of viral families presenting papillomavirus and picornaviruses and, interestingly, some viruses linked to immunosuppression.

CONCLUSIONS

This study shows the utility of building-level wastewater-based epidemiology as an effective tool for monitoring the presence of viruses circulating within specific age groups. It provides valuable insights for public health monitoring and epidemiological studies.

Seamless integration of sewer system topology and tree location data: An algorithm to diagnose the potential impact of tree roots on pipes and propose rearrangement solutions

Wastewater networks are subject to several threats leading to wastewater leakages and public health hazards. External elements such as natural factors and human activities are common causes of wastewater leakages and require more in-depth analysis. Prevention and rehabilitation work is essential to secure wastewater networks and avoid pipe failures. This work presents a new algorithm that allows for the seamless integration of sewer topology and tree location data to diagnose the potential impact of tree roots on pipes. The algorithm also proposes tree rearrangement options that balance the cost of tree rearrangement with the cost of pipe repair. The paper also showcases a real-world case study in the city of Girona to evaluate the performance of the presented algorithms for a specific case focusing on tree roots as a natural factor. Results show that it is possible to optimally rearrange a number of the trees with the greatest impact, significantly minimizing pipe failures and wastewater leakages (82% risk reduction with only rearranging a 12% of the most impactful trees). The rearrangement solution not only protects the environment and prevents public health hazards, but also achieves a positive economic payback during the operational period of the pipes, saving up to 1.33M€ for a tree rearrangement of 7%. The presented methodology is applicable to other natural or human factors.

Zooming in to the neighborhood level: A year-long wastewater-based epidemiology monitoring campaign for COVID-19 in small intraurban catchments

In recent years, wastewater-based epidemiology (WBE) has emerged as a valuable and cost-effective tool for monitoring the prevalence of COVID-19. Large-scale monitoring efforts have been implemented in numerous countries, primarily focusing on sampling at the entrance of wastewater treatment plants (WWTPs) to cover a large population. However, sampling at a finer spatial scale, such as at the neighborhood level (NGBs), pose new challenges, including the absence of composite sampling infrastructure and increased uncertainty due to the dynamics of small catchments. This study aims to investigate the feasibility and accuracy of WBE when deployed at the neighborhood level (sampling in sewers) compared to the city level (sampling at the entrance of a WWTP). To achieve this, we deployed specific WBE sampling stations at the intraurban scale within three NGBs in Barcelona, Spain. The study period covers the 5th and the 6th waves of COVID-19 in Spain, spanning from March 2021 to March 2022, along with the WWTP downstream from the NGBs. The results showed a strong correlation between the dynamics of COVID-19 clinical cases and wastewater SARS-CoV-2 loads at both the NGB and city levels. Notably, during the 5th wave, which was dominated by the Delta SARS-CoV-2 variant, wastewater loads were higher than during the 6th wave (Omicron variant), despite a lower number of clinical cases recorded during the 5th wave. The correlations between wastewater loads and clinical cases at the NGB level were stronger than at the WWTP level. However, the early warning potential varied across neighborhoods and waves, with some cases showing a one-week early warning and others lacking any significant early warning signal. Interestingly, the prevalence of COVID-19 did not exhibit major differences among NGBs with different socioeconomic statuses.

ediblecity: an R package to model and estimate the benefits of urban agriculture

Urban agriculture is gaining attraction to become one of the pillars of the urban ecological transition and to increase food security in an urbanized planet. However, there is a lack of systematic quantification of the benefits provided by urban agriculture solutions. In this paper, we present an R package to estimate several indicators related to benefits of urban agriculture. The goal is to provide a tool for researchers and practitioners interested in the impacts of urban agriculture. The ediblecity package provides functions to calculate 8 indicators: urban heat island, runoff prevention, green areas accessibility, NO 2 sequestration, jobs created in commercial gardens, volunteers involved in community gardens, green per capita and, finally, food production. Moreover, the package also provides a function to generate scenarios with different implementations of urban agriculture. We illustrate the use of the package by comparing three scenarios in a neighborhood of Girona (Spain), which is included in the package as an example dataset. There, we compare scenarios with an increasing amount of urban agriculture solutions. The ediblecity package is open-source software. This allows other R developers to contribute to the package, providing new functionalities or improving the existing ones.

N-Nitrosamines and their precursors in wastewater effluents from selected industries in Spain

N-nitrosamines (NAs), and N-nitrosodimethylamine (NDMA) in particular, are hazardous disinfection byproducts (DBPs) relevant when wastewater impacts drinking water sources and, in water reuse practices. Our study investigates the concentrations of NDMA and five additional NAs and their precursors in industrial wastewater effluents. Aiming to identify potential differences between industrial typologies, wastewaters from 38 industries belonging to 11 types of the UN International Standard Industrial Classification of All Economic Activities system (ISIC) were analysed. Results show that the presence of most NAs and their precursors cannot be linked to a specific industry type as these were in general very different within the classes. Nevertheless, N-nitrosomethylethylamine (NMEA) and N-nitrosopiperidine (NPIP) as well as precursors for N-nitrosodiethylamine (NDEA), NPIP and N-nitrosodibuthylamine (NDBA) could be rank with different concentrations between ISIC classes (p-value < 0.05). Specific industrial wastewater with notable high concentrations of NAs and their precursors were identified too. The effluents with the highest concentration of NDMA belong to the ISIC C2011 class (Manufacture of basic chemical), while the effluents with the highest concentration of NDMA precursors were from the ISIC C1511 class (Tanning and dressing of leather; dressing and dyeing of fur). Other relevant NAs found were NDEA in ISIC class B0810 (Quarrying of stone, sand, and clay) and ISIC class C2029 (Manufacture of other chemical products).

Surveillance of SARS-CoV-2 in sewage from buildings housing residents with different vulnerability levels

During the last three years, various restrictions have been set up to limit the transmission of the Coronavirus Disease (COVID-19). While these rules apply at a large scale (e.g., country-wide level) human-to-human transmission of the virus that causes COVID-19, the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), occurs at a small scale. Different preventive policies and testing protocols were implemented in buildings where COVID-19 poses a threat (e.g., elderly residences) or constitutes a disruptive force (e.g., schools). In this study, we sampled sewage from different buildings (a school, a university campus, a university residence, and an elderly residence) that host residents of different levels of vulnerability. Our main goal was to assess the agreement between the SARS-CoV-2 concentration in wastewater and the policies applied in these buildings. All buildings were sampled using passive samplers while 24 h composite samples were also collected from the elderly residence. Results showed that passive samplers performed comparably well to composite samples while being cost-effective to keep track of COVID-19 prevalence. In the elderly residence, the comparison of sampling protocols (passive vs. active) combined with the strict clinical testing allowed us to compare the sensitivities of the two methods. Active sampling was more sensitive than passive sampling, as the former was able to detect a COVID-19 prevalence of 0.4 %, compared to a prevalence of 2.2 % for passive sampling. The number of COVID-19-positive individuals was tracked clinically in all the monitored buildings. More frequent detection of SARS-CoV-2 in wastewater was observed in residential buildings than in non-residential buildings using passive samplers. In all buildings, sewage surveillance can be used to complement COVID-19 clinical testing regimes, as the detection of SARS-CoV-2 in wastewater remained positive even when no COVID-19-positive individuals were reported. Passive sampling is useful for building managers to adapt their COVID-19 mitigation policies.

Optimal design of water reuse networks in cities through decision support tool development and testing

Water scarcity and droughts are an increasing issue in many parts of the world. In the context of urban water systems, the transition to circularity may imply wastewater treatment and reuse. Planning and assessment of water reuse projects require decision-makers evaluating the cost and benefits of alternative scenarios. Manual or semi-automatic approaches are still common practice for planning both drinking and reclaimed water distribution networks. This work illustrates a decision support tool that, based on open data sources and graph theory coupled to greedy optimization algorithms, is able to automatically compute the optimal reclaimed water network for a given scenario. The tool provides not only the maximum amount of served reclaimed water per unit of invested cost, but also the length and diameters of the pipes required, the location and size of storage tanks, the population served, and the construction costs, i.e., everything under the same architecture. The usefulness of the tool is illustrated in two different but complementary cities in terms of size, density, and topography. The construction cost of the optimal water reclaimed network for a city of approximately 100,000 inhabitants is estimated to be in the range of €0.17-0.22/m³ (for a payback period of 30 years).

Could we estimate industrial wastewater flows composition using the UN-ISIC classification system?

Although we have extensive datasets on the location and typology of industries, we do not know much on their generated and discharged wastewater. This lack of information compromises the achievement of the sustainable development goals focused on water (Sustainable Development Goal 6) in Europe and globally. Thus, our goal was to assess to which degree the chemical composition of industrial wastewater could be estimated based on the industry's typology according to its International Standard Industrial Classification of All Economic Activities (ISIC) class. We collected wastewater effluent water samples from 60 industrial wastewater effluents (before any wastewater treatment process), accounting for 5 samples each of 12 ISIC classes, analyzed the composition of key contaminants (i.e. European Commission rated priority compounds and watchlist), and statistically assessed the similarities and differences amongst ISIC classes using ordination and random forest analyses. The results showed statistically significant linkages between most ISIC classes and the composition of produced wastewater. Among the analytical parameters measured, the random forest methodology allowed identifying a sub-set particularly relevant for classification or eventual contamination prediction based on ISIC class. This is an important applied research topic with strong management implications to (i) determine pollution emission caps for each individual ISIC class, (ii) define monitoring schemes to sample and analyze industrial wastewater, and (iii) enable predicting pollutant loads discharged in river basins with scarce information. These encouraging results urge us to expand our work into other ISIC classes and water quality parameters to draw a full picture of the relationship between ISIC classes and produced wastewater.

Applicability of an on-line solid-phase extraction liquid chromatography - tandem mass spectrometry for the wastewater-based assessment of human exposure to chemicals from personal care and household products

Wastewater-based epidemiology (WBE) can be a useful complementary approach to assess human exposure to potentially harmful chemicals, including those from personal care and household products. In this work, a fully automated multiresidue method, based on on-line solid-phase extraction liquid chromatography - tandem mass spectrometry, was developed for the determination of 27 biomarkers of human exposure to selected chemicals from personal care and household products, including parabens, UV filters, phthalates and alternative plasticizers, phosphorous flame retardants/plasticizers (PFRs), and bisphenols. These biomarkers include both the parent compounds and their human metabolites. In addition, two oxidative stress biomarkers, 8-epi-prostaglandin F2α and 4-hydroxy nonenal mercapturic acid, were also considered in the study. The method was carefully optimized to tackle the challenges of analyzing compounds with different physico-chemical properties in a highly complex raw wastewater matrix, while model experiments were performed to investigate filtration losses and analyte stability. The applicability of the developed method was tested by analyzing raw wastewater from four European cities: Antwerp, Brussels (Belgium), Girona (Spain), and Zagreb (Croatia). Twenty-one biomarkers (10 parent compounds and 11 metabolites) were detected in all analyzed wastewater samples. The parent compounds with the highest mass loads were PFRs, parabens, and bisphenol S, while phthalate monoesters were the most prominent metabolites. The mass loads of most compounds were quite similar across cities, but geographic differences were observed for some biomarkers, such as metabolites of phthalates and alternative plasticizers. Exposure was then assessed for seven substances for which quantitative urinary excretion data are known. Our results indicate that safe reference values were exceeded for several contaminants, including butylated phthalates, bisphenol A, and tris(2-butoxyethyl) phosphate, particularly for toddlers. With this relatively simple method, which requires less sample manipulation, it is possible to promptly identify and monitor exposure to harmful chemicals at the population level using the WBE approach.

The Catalan Surveillance Network of SARS-CoV-2 in Sewage: design, implementation, and performance

Wastewater-based epidemiology has shown to be an efficient tool to track the circulation of SARS-CoV-2 in communities assisted by wastewater treatment plants (WWTPs). The challenge comes when this approach is employed to help Health authorities in their decision-making. Here, we describe the roadmap for the design and deployment of SARSAIGUA, the Catalan Surveillance Network of SARS-CoV-2 in Sewage. The network monitors, weekly or biweekly, 56 WWTPs evenly distributed across the territory and serving 6 M inhabitants (80% of the Catalan population). Each week, samples from 45 WWTPs are collected, analyzed, results reported to Health authorities, and finally published within less than 72 h in an online dashboard (https://sarsaigua.icra.cat). After 20 months of monitoring (July 20–March 22), the standardized viral load (gene copies/day) in all the WWTPs monitored fairly matched the cumulative number of COVID-19 cases along the successive pandemic waves, showing a good fit with the diagnosed cases in the served municipalities (Spearman Rho = 0.69). Here we describe the roadmap of the design and deployment of SARSAIGUA while providing several open-access tools for the management and visualization of the surveillance data.

Optimal selection of monitoring sites in cities for SARS-CoV-2 surveillance in sewage networks

Selecting sampling points to monitor traces of SARS-CoV-2 in sewage at the intra-urban scale is no trivial task given the complexity of the networks and the multiple technical, economic and socio-environmental constraints involved. This paper proposes two algorithms for the automatic selection of sampling locations in sewage networks. The first algorithm, is for the optimal selection of a predefined number of sampling locations ensuring maximum coverage of inhabitants and minimum overlapping amongst selected sites (static approach). The second is for establishing a strategy of iterations of sample&analysis to identify patient zero and hot spots of COVID-19 infected inhabitants in cities (dynamic approach). The algorithms are based on graph-theory and are coupled to a greedy optimization algorithm. The usefulness of the algorithms is illustrated in the case study of Girona (NE Iberian Peninsula, 148,504 inhabitants). The results show that the algorithms are able to automatically propose locations for a given number of stations. In the case of Girona, always covering more than 60% of the manholes and with less than 3% of them overlapping amongst stations. Deploying 5, 6 or 7 stations results in more than 80% coverage in manholes and more than 85% of the inhabitants. For the dynamic sensor placement, we demonstrate that assigning infection probabilities to each manhole as a function of the number of inhabitants connected reduces the number of iterations required to detect the zero patient and the hot spot areas.

A framework for model-based assessment of resilience in water resource recovery facilities against power outage

Current practice to enhance resilience in Water Resource Recovery Facilities (WRRFs) is to ensure redundancy or back-up for most critical equipment (e.g. pumps or blowers). Model-based assessment allows evaluation of different strategies for quantitatively and efficiently enhancing resilience and justifying the allocation of resources. The goal of this study is to provide guidance for the development of tailored deterministic models of full-scale WRRFs. A framework for model-based resilience assessment is proposed that provides guidance on data collection, model selection, model calibration and scenario analysis. The framework is embedded into the Good Modeling Practice (GMP) Unified Protocol, providing a new application for resilience assessment and an initial set of stressors for WRRFs. The usefulness of the framework is illustrated through a resilience assessment of the WRRF of Girona against power outage. Results show that, for the Girona facility, limited energy back-up can cause non-compliance of WRRF discharge limits in the case of a blower power shut-down of 6 h, and around 12 h when the blower shut-down is also combined with a shut-down of the recirculation pumps. The best option to enhance resilience would be increasing the power back-up by 218%, which allows the plant to run with recirculation pumps and blowers at minimum capacity. In such a case, resilience can be further enhanced by manipulating the air supply valves to optimise the air distribution, to balance oxygen needs in each reactor with the overall system pressure. We conclude that, with industry consensus on what is considered an acceptable level of resilience, a framework for resilience assessment would be a useful tool to enhance the resilience of our current water infrastructure. Further research is needed to establish if the permit structure should accommodate levels sof functionality to account for stress events.

Nature-based solutions in the urban context: terminology, classification and scoring for urban challenges and ecosystem services

The concept of Nature-Based Solutions (NBS) has emerged to foster sustainable development by transversally addressing social, economic, and environmental urban challenges. However, there is still a considerable lack of agreement on the conceptualization of NBS, especially concerning typologies, nomenclature, and performance assessments in terms of ecosystem services (ES) and urban challenges (UC). Therefore, this article consolidates the knowledge from 4 European projects to set a path for a common understanding of NBS and thus, facilitate their mainstreaming. To do so, firstly, we performed elicitation workshops to develop an integrative list of NBS, based on the identification of overlaps among NBS from different projects. The terminologies were formalized via web-based surveys. Secondly, the NBS were clustered, following a conceptual hierarchical classification. Thirdly, we developed an integrative assessment of NBS performance (ES and UC) based on the qualitative evaluations from each project. Afterwards, we run a PCA and calculated the evenness index to explore patterns among NBS. The main conceptual advancement resides in providing a list of 32 NBS and putting forward two novel NBS categories: NBS units (NBS_u) that are stand-alone green technologies or green urban spaces, which can be combined with other solutions (nature-based or not); NBS interventions (NBS_i) that refer to the act of intervening in existing ecosystems and in NBS_u, by applying techniques to support natural processes. The statistical analysis suggests that NBS_u are more versatile than NBS_i in terms of UC and ES. Moreover, the results of the integrative assessment of NBS performance suggest a greater agreement concerning the role of NBS in addressing environmental UC, cultural and regulating ES than regarding socio-economic UC and supporting and provision ES. Finally, the 'green factor' and the replication of non-intensive practices occurring in nature seem to be key criteria for practitioners to identify a particular solution as an NBS.

Climate change impact on EU rivers' dilution capacity and ecological status

Impacts from urban wastewater treatment plants (WWTP) to receiving riverine surface water bodies (SWBs) depend on the load of contaminants discharged, as well as on their dilution capacity. Yet, climate change impacts on such dilution capacity and ultimately on the SWBs ecological status remain unclear. Here, we assess SWBs dilution capacity across the European continent to identify most vulnerable areas using information from centralized European databases. SWBs´ future dilution factor values are estimated based on representative concentration pathway scenarios impacts on rivers flow, and likely changes in European SWBs´ ecological status foretold. Results show that dilution factor in Europe increases by 5.4% in average. Yet, climate change effects are found to lead to a consistent dilution factor decrease for 11% of the 40074 European SWBs receiving WWTP discharge for the early century. This share reaches 17% for the midcentury period. We estimate that up to 42% of the SWBs receiving WWTP discharges and currently reaching a good ecological status show a 0.7 probability to have their ecological status downgraded due to climate change. Sites more vulnerable are located in the Mediterranean countries. Our findings highlight that climate change mitigation is essential for maintaining good ecological status in European SWBs.

Can source control of pharmaceuticals decrease the investment needs in urban wastewater infrastructure?

The source control of pharmaceuticals involves influencing the everyday consumption volume and compound choice. This paper evaluates how source control contributes to protecting the environmental health and decreasing the investment needs in urban wastewater infrastructure. Different levels of reduction in diclofenac consumption (as recommended by the European Medicines Agency) compensated by equivalent increases in naproxen consumption (a less environmentally harmful compound) are evaluated. The different loads of compounds are fed into a microcontaminant fate and transport model of the Llobregat river basin (Spain) to assess the investment needs in tertiary treatment to reach diclofenac and naproxen concentrations below environmental quality standards. The results show that, despite the implementation of source control measures, tertiary treatment upgrades are still required in every scenario evaluated. Even though source control of pharmaceuticals decreases the investment needs in urban wastewater infrastructure, apparent concentrations reductions (i.e. statistically significant differences relative to the reference situation) are only observed in drastic substitutions of diclofenac by naproxen (a reduction in the total diclofenac consumption by 73% and a corresponding increase in naproxen consumption). The results also show that Spain is on good track with regards to the substitution of diclofenac by naproxen (among the top 5 in Europe), and this paper shows how positive this substitution can be for the environment.

Wastewater-based epidemiology to assess human exposure to personal care and household products - A review of biomarkers, analytical methods, and applications

Humans are nowadays exposed to numerous chemicals in our day-to-day life, including parabens, UV filters, phosphorous flame retardants/plasticizers, bisphenols, phthalates and alternative plasticizers, which can have different adverse effects to human health. Estimating human's exposure to these potentially harmful substances is, therefore, of paramount importance. Human biomonitoring (HBM) is the existing approach to assess exposure to environmental contaminants, which relies on the analysis of specific human biomarkers (parent compounds and/or their metabolic products) in biological matrices from individuals. The main drawback is its implementation, which involves complex cohort studies. A novel approach, wastewater-based epidemiology (WBE), involves estimating exposure from the analysis of biomarkers in sewage (a pooled urine and feces sample of an entire population). One of the key challenges of WBE is the selection of biomarkers which are specific to human metabolism, excreted in sufficient amounts, and stable in sewage. So far, literature data on potential biomarkers for estimating exposure to these chemicals are scattered over numerous pharmacokinetic and HBM studies. Hence, this review provides a list of potential biomarkers of exposure to more than 30 widely used chemicals and report on their urinary excretion rates. Furthermore, the potential and challenges of WBE in this particular field is discussed through the review of pioneer WBE studies, which for the first time explored applicability of this novel approach to assess human exposure to environmental contaminants. In the future, WBE could be potentially applied as an "early warning system", which could promptly identify communities with the highest exposure to environmental contaminants.

When the fourth water and digital revolution encountered COVID-19

The ongoing COVID-19 pandemic is, undeniably, a substantial shock to our civilization which has revealed the value of public services that relate to public health. Ensuring a safe and reliable water supply and maintaining water sanitation has become ever more critical during the pandemic. For this reason, researchers and practitioners have promptly investigated the impact associated with the spread of SARS-CoV-2 on water treatment processes, focusing specifically on water disinfection. However, the COVID-19 pandemic impacts multiple aspects of the urban water sector besides those related to the engineering processes, including sanitary, economic, and social consequences which can have significant effects in the near future. Furthermore, this outbreak appears at a time when the water sector was already experiencing a fourth revolution, transitioning toward the digitalisation of the sector, which redefines the Water-Human-Data Nexus. In this contribution, a product of collaboration between academics and practitioners from water utilities, we delve into the multiple impacts that the pandemic is currently causing and their possible consequences in the future. We show how the digitalisation of the water sector can provide useful approaches and tools to help address the impact of the pandemic. We expect this discussion to contribute not only to current challenges, but also to the conceptualization of new projects and the broader task of ameliorating climate change.

The application of life cycle assessment (LCA) to wastewater treatment: A best practice guide and critical review

Life cycle assessment (LCA) has been widely applied in the wastewater industry, but inconsistencies in assumptions and methods have made it difficult for researchers and practitioners to synthesize results from across studies. This paper presents a critical review of published LCAs related to municipal wastewater management with a focus on developing systematic guidance for researchers and practitioners to conduct LCA studies to inform planning, design, and optimization of wastewater management and infrastructure (wastewater treatment plants, WWTPs; collection and reuse systems; related treatment technologies and policies), and to support the development of new technologies to advance treatment objectives and the sustainability of wastewater management. The paper guides the reader step by step through LCA methodology to make informed decisions on i) the definition of the goal and scope, ii) the selection of the functional unit and system boundaries, iii) the selection of variables to include and their sources to obtain inventories, iv) the selection of impact assessment methods, and v) the selection of an effective approach for data interpretation and communication to decision-makers.

The Fourth-Revolution in the Water Sector Encounters the Digital Revolution

The so-called fourth revolution in the water sector will encounter the Big data and Artificial Intelligence (AI) revolution. The current data surplus stemming from all types of devices together with the relentless increase in computer capacity is revolutionizing almost all existing sectors, and the water sector will not be an exception. Combining the power of Big data analytics (including AI) with existing and future urban water infrastructure represents a significant untapped opportunity for the operation, maintenance, and rehabilitation of urban water infrastructure to achieve economic and environmental sustainability. However, such progress may catalyze socio-economic changes and cross sector boundaries (e.g., water service, health, business) as the appearance of new needs and business models will influence the job market. Such progress will impact the academic sector as new forms of research based on large amounts of data will be possible, and new research needs will be requested by the technology industrial sector. Research and development enabling new technological approaches and more effective management strategies are needed to ensure that the emerging framework for the water sector will meet future societal needs. The feature further elucidates the complexities and possibilities associated with such collaborations.

Assessing stormwater control measures using modelling and a multi-criteria approach

This paper presents a methodology for assessing the selection of stormwater control measures (SCM) within an urban drainage system that combines hydrological-hydraulic modelling and multi-criteria analysis (MCA). The methodology's utility is illustrated on urban catchment in the city of Girona, Spain. The SWMM model was applied and calibrated to simulate SCM scenarios. Seven scenarios were evaluated consisting of one grey infrastructure measure using underground storage tank and three nature-based SCM i.e. infiltration basins, infiltration trenches, green roofs, and combinations thereof. These scenarios were evaluated with MCA including combined sewer overflow (CSO) reduction, CAPEX, OPEX, amenity, biodiversity, and feasibility regarding ownership. The results show that the scenario that included only infiltration basins was most favourable, followed by the scenario which combined infiltration basins and trenches. The underground storage tank was the least favourable with the lowest grade, due to high CAPEX and OPEX, and due to single functionality.

Balancing environmental quality standards and infrastructure upgrade costs for the reduction of microcontaminant loads in rivers

Investments for upgrading wastewater treatment plants (WWTPs) with tertiary treatment to reduce microcontaminant loads in surface waters at a catchment scale can be daunting. These investments are highly sensitive to the selection of environmental quality standards (EQSs) for the target microcontaminants. Our hypothesis is that there is a balance between EQS selection and investment that needs to be considered in decision-making. We used a customized microcontaminant fate and transport model coupled to an optimization algorithm to validate this hypothesis in the Llobregat river basin and for the pharmaceutical compound diclofenac. The algorithm optimizes the number of WWTPs in this catchment requiring an upgrade to minimize the total amount of diclofenac that exceeds the EQS in every river section and the total cost. We simulated and optimized 40 scenarios representing a combination of 4 potential EQSs (10, 30, 50 and 100 ng L^-1), 5 levels of uncertainty bounds in the predictions of river concentrations and 2 hydrological scenarios (average flows, flows annually exceeding 30% of the days; and environmental flows, flows annually exceeding 99% of the days). The results showthat there is a nonlinear relationship between the EQS and the required investment. The investment increases by 100% from an EQS of 100 ng L^-1 to 10 ng L^-1, significantly increasing (by 60%) from 30 to 10 ng L^-1. Thus, establishing an EQS of 30 ng L^-1 would balance environmental protection and costs. The selection of the hydrological conditions also plays a key role in the upgrade analysis because the costs for environmental flows are 50% higher than for average flows. Finally, we highlight that the investment in research would allow the reduction of uncertainties, hence allowing more qualified decisions to be made and a reduction in the WWTP upgrade costs (up to 4 €·household^-1·year^-1).

Dynamic air supply models add realism to the evaluation of control strategies in water resource recovery facilities

This paper introduces the application of a fully dynamic air distribution model integrated with a biokinetic process model and a detailed process control model. By using a fully dynamic air distribution model, it is possible to understand the relationships between aeration equipment, control algorithms, process performance, and energy consumption, thus leading to a significantly more realistic prediction of water resource recovery facility (WRRF) performance. Consequently, this leads to an improved design of aeration control strategies and equipment. A model-based audit has been performed for the Girona WRRF with the goal of providing a more objective evaluation of energy reduction strategies. Currently, the Girona plant uses dissolved oxygen control and has been manually optimised for energy consumption. Results from a detailed integrated model show that the implementation of an ammonia-based aeration controller, a redistribution of the diffusers, and the installation of a smaller blower lead to energy savings between 12 and 21%, depending on wastewater temperature. The model supported the development of control strategies that counter the effects of current equipment limitations, such as tapered diffuser distribution, or over-sized blowers. The latter causes an intermittent aeration pattern with blowers switching on and off, increasing wear of the equipment.

Are inflatable play structures really safe for our children?

PURPOSE

The frequency of injuries sustained while playing on inflatable toys such as bouncy castles have rapidly increased. These supposedly safe structures are likely unsafe. The objective of this review was to investigate the risk that these attractions represent and the necessary measures to minimize risk of accidents.

METHODS

We conducted a prospective study of 114 patients over a period of one year (2015 to 2016). Demographic data collected included: age, gender, anatomical location and side of involvement as well as supervision of the child whilst on the bouncy castle. The extracted data include mechanism of injury and risk factors, i.e. lack of supervision of the child, amounts of users jumping at the same time.

RESULTS

The injuries were slightly more frequent in male than female children; 2:1 up to six years of age. From the age of ten to 14 years the ration evened to 1:1, the higher incidence in female children was between the ages of six to eight years.The most common injuries were to the humerus, followed by the distal radius. Only 28% of the parents said they were supervising while the child was jumping.

CONCLUSION

Injuries associated with inflatable bouncers have increased over time. The main risk factors: were lack of effective adult supervision and the shared use by an excessive number of participants of different ages and weights.These considerations lead to the conclusion that there is a necessity to enhance child health surveillance and to consider limiting bouncer usage to children over the age of six years, to prevent and control injuries and to minimize their consequences.

LEVEL OF EVIDENCE

II - prospective study.

Assessing Urban Wastewater System Upgrades Using Integrated Modeling, Life Cycle Analysis, and Shadow Pricing

This study assesses the environmental impacts of four measures proposed for upgrading of the urban wastewater system of Eindhoven and the Dommel River in The Netherlands, against the base case, "do-nothing" option. The measures aim to reduce the overall environmental impact of the Eindhoven urban wastewater system (UWS) by targeting river dissolved oxygen depletion and ammonia peaks, reducing combined sewer overflows, and enhancing nutrient removal. The measures are evaluated using a life cycle analysis with the boundaries including the receiving river section by means of an integrated model of the UWS. An uncertainty analysis of the estimated impacts has been performed to support the outcomes. The study also uses the economic concept of shadow prices to assign relative weights of socio-economic importance to the estimated life cycle impacts. This novel integration of tools complements the assessments of this UWS with the inclusion of long-term global environmental impacts and the investigation of trade-offs between different environmental impacts through a single monetary unit. The results support the selection of deeper clarifiers as the most environmentally beneficial measure for upgrade.

An atypical case of elbow fracture Bilateral Capitellum Humeri Fracture in a Teenage

Fractures of the capitellum are rare injures of the elbow rarely seen in adolescents. We report a case of a 14 year-old boy who sustained a bilateral Hahn-Steinthal type fracture of his capitelum humeri. To our knowledge, such bilateral injury has not been reported before in teenagers. This paper reviews the literature regarding the epidemiology, classification and management of this rare pediatric capitellar fracture.

Optimal flow sensor placement on wastewater treatment plants

Obtaining high quality data collected on wastewater treatment plants is gaining increasing attention in the wastewater engineering literature. Typical studies focus on recognition of faulty data with a given set of installed sensors on a wastewater treatment plant. Little attention is however given to how one can install sensors in such a way that fault detection and identification can be improved. In this work, we develop a method to obtain Pareto optimal sensor layouts in terms of cost, observability, and redundancy. Most importantly, the resulting method allows reducing the large set of possibilities to a minimal set of sensor layouts efficiently for any wastewater treatment plant on the basis of structural criteria only, with limited sensor information, and without prior data collection. In addition, the developed optimization scheme is fast. Practically important is that the number of sensors needed for both observability of all flows and redundancy of all flow sensors is only one more compared to the number of sensors needed for observability of all flows in the studied wastewater treatment plant configurations.

Analysis of the uncertainty in the monetary valuation of ecosystem services--A case study at the river basin scale

Ecosystem services provide multiple benefits to human wellbeing and are increasingly considered by policy-makers in environmental management. However, the uncertainty related with the monetary valuation of these benefits is not yet adequately defined or integrated by policy-makers. Given this background, our aim was to quantify different sources of uncertainty when performing monetary valuation of ecosystem services, in order to provide a series of guidelines to reduce them. With an example of 4 ecosystem services (i.e., water provisioning, waste treatment, erosion protection, and habitat for species) provided at the river basin scale, we quantified the uncertainty associated with the following sources: (1) the number of services considered, (2) the number of benefits considered for each service, (3) the valuation metrics (i.e. valuation methods) used to value benefits, and (4) the uncertainty of the parameters included in the valuation metrics. Results indicate that the highest uncertainty was caused by the number of services considered, as well as by the number of benefits considered for each service, whereas the parametric uncertainty was similar to the one related to the selection of valuation metric, thus suggesting that the parametric uncertainty, which is the only uncertainty type commonly considered, was less critical than the structural uncertainty, which is in turn mainly dependent on the decision-making context. Given the uncertainty associated to the valuation structure, special attention should be given to the selection of services, benefits and metrics according to a given context.

Life cycle assessment of urban wastewater systems: Quantifying the relative contribution of sewer systems

This study aims to propose a holistic, life cycle assessment (LCA) of urban wastewater systems (UWS) based on a comprehensive inventory including detailed construction and operation of sewer systems and wastewater treatment plants (WWTPs). For the first time, the inventory of sewers infrastructure construction includes piping materials and aggregates, manholes, connections, civil works and road rehabilitation. The operation stage comprises energy consumption in pumping stations together with air emissions of methane and hydrogen sulphide, and water emissions from sewer leaks. Using a real case study, this LCA aims to quantify the contributions of sewer systems to the total environmental impacts of the UWS. The results show that the construction of sewer infrastructures has an environmental impact (on half of the 18 studied impact categories) larger than both the construction and operation of the WWTP. This study highlights the importance of including the construction and operation of sewer systems in the environmental assessment of centralised versus decentralised options for UWS.

Occurrence and in-stream attenuation of wastewater-derived pharmaceuticals in Iberian rivers

A multitude of pharmaceuticals enter surface waters via discharges of wastewater treatment plants (WWTPs), and many raise environmental and health concerns. Chemical fate models predict their concentrations using estimates of mass loading, dilution and in-stream attenuation. However, current comprehension of the attenuation rates remains a limiting factor for predictive models. We assessed in-stream attenuation of 75 pharmaceuticals in 4 river segments, aiming to characterize in-stream attenuation variability among different pharmaceutical compounds, as well as among river segments differing in environmental conditions. Our study revealed that in-stream attenuation was highly variable among pharmaceuticals and river segments and that none of the considered pharmaceutical physicochemical and molecular properties proved to be relevant in determining the mean attenuation rates. Instead, the octanol-water partition coefficient (Kow) influenced the variability of rates among river segments, likely due to its effect on sorption to sediments and suspended particles, and therefore influencing the balance between the different attenuation mechanisms (biotransformation, photolysis, sorption, and volatilization). The magnitude of the measured attenuation rates urges scientists to consider them as important as dilution when aiming to predict concentrations in freshwater ecosystems.

Ecosystem-based management of a Mediterranean urban wastewater system: a sensitivity analysis of the operational degrees of freedom

Urban wastewater systems discharge organic matter, nutrients and other pollutants (including toxic substances) to receiving waters, even after removing more than 90% of incoming pollutants from human activities. Understanding their interactions with the receiving water bodies is essential for the implementation of ecosystem-based management strategies. Using mathematical modeling and sensitivity analysis we quantified how 19 operational variables of an urban wastewater system affect river water quality. The mathematical model of the Congost system (in the Besòs catchment, Spain) characterizes the dynamic interactions between sewers, storage tanks, wastewater treatment plants and the river. The sensitivity analysis shows that the use of storage tanks for peak shaving and the use of a connection between two neighboring wastewater treatment plants are the most important factors influencing river water quality. We study how the sensitivity of the water quality variables towards changes in the operational variables varies along the river due to discharge locations and river self-purification processes. We demonstrate how to use the approach to identify interactions and how to discard non-influential operational variables.

Balancing effluent quality, economic cost and greenhouse gas emissions during the evaluation of (plant-wide) control/operational strategies in WWTPs

The objective of this paper was to show the potential additional insight that result from adding greenhouse gas (GHG) emissions to plant performance evaluation criteria, such as effluent quality (EQI) and operational cost (OCI) indices, when evaluating (plant-wide) control/operational strategies in wastewater treatment plants (WWTPs). The proposed GHG evaluation is based on a set of comprehensive dynamic models that estimate the most significant potential on-site and off-site sources of CO₂, CH₄ and N₂O. The study calculates and discusses the changes in EQI, OCI and the emission of GHGs as a consequence of varying the following four process variables: (i) the set point of aeration control in the activated sludge section; (ii) the removal efficiency of total suspended solids (TSS) in the primary clarifier; (iii) the temperature in the anaerobic digester; and (iv) the control of the flow of anaerobic digester supernatants coming from sludge treatment. Based upon the assumptions built into the model structures, simulation results highlight the potential undesirable effects of increased GHG production when carrying out local energy optimization of the aeration system in the activated sludge section and energy recovery from the AD. Although off-site CO₂ emissions may decrease, the effect is counterbalanced by increased N₂O emissions, especially since N₂O has a 300-fold stronger greenhouse effect than CO₂. The reported results emphasize the importance and usefulness of using multiple evaluation criteria to compare and evaluate (plant-wide) control strategies in a WWTP for more informed operational decision making.

Including Life Cycle Assessment for decision-making in controlling wastewater nutrient removal systems

This paper focuses on the use of Life Cycle Assessment (LCA) to evaluate the performance of seventeen control strategies in wastewater treatment plants (WWTPs). It tackles the importance of using site-specific factors for nutrient enrichment when decision-makers have to select best operating strategies. Therefore, the LCA evaluation is repeated for three different scenarios depending on the limitation of nitrogen (N), phosphorus (P), or both, when evaluating the nutrient enrichment impact in water bodies. The LCA results indicate that for treated effluent discharged into N-deficient aquatic systems (e.g. open coastal areas) the most eco-friendly strategies differ from the ones dealing with discharging into P-deficient (e.g. lakes and rivers) and N&P-deficient systems (e.g. coastal zones). More particularly, the results suggest that strategies that promote increased nutrient removal and/or energy savings present an environmental benefit for N&P and P-deficient systems. This is not the case when addressing N-deficient systems for which the use of chemicals (even for improving N removal efficiencies) is not always beneficial for the environment. A sensitivity analysis on using weighting of the impact categories is conducted to assess how value choices (policy decisions) may affect the management of WWTPs. For the scenarios with only N-limitation, the LCA-based ranking of the control strategies is sensitive to the choice of weighting factors, whereas this is not the case for N&P or P-deficient aquatic systems.

Integration of freshwater environmental policies and wastewater treatment plant management

In the last decade the political awareness of river water quality issues has grown substantially over the world and legislation is accordingly adapting. In the European Union (EU), two different directives regulate separately the characteristics of the discharged water and the chemical status of the receiving freshwater ecosystem. On the one hand, the characteristics of the urban effluents are regulated by the EU Directive 91/271/EEC, which defines limits on different elements set in the form of both static emission limits and minimum percentage load reductions. On the other hand, the characteristics of the receiving freshwater ecosystems are described in the EU Water Framework Directive (2000/60/EEC), which sets minimum 'good' chemical and ecological status in water bodies that should be achieved by 2015, and aims for an ecosystem-based management. With the support of an example, we show that there is a gap in these EU environmental policies leading to non-integrated management, which may result on adverse environmental and economical consequences. We believe that these policies should be updated and tuned to account for an integrated perspective, allowing a more efficient and sustainable management of wastewater treatment plants, maximizing the ecological, economical and social benefits of the system as a whole.

Modelling and monitoring of integrated urban wastewater systems: review on status and perspectives

While the general principles and modelling approaches for integrated management/modelling of urban water systems already present a decade ago still hold, in recent years aspects like model interfacing and wastewater treatment plant (WWTP) influent generation as complements to sewer modelling have been investigated and several new or improved systems analysis methods have become available. New/improved software tools coupled with the current high computational capacity have enabled the application of integrated modelling to several practical cases, and advancements in monitoring water quantity and quality have been substantial and now allow the collecting of data in sufficient quality and quantity to permit using integrated models for real-time applications too. Further developments are warranted in the field of data quality assurance and efficient maintenance.

Benchmark simulation models, quo vadis?

As the work of the IWA Task Group on Benchmarking of Control Strategies for wastewater treatment plants (WWTPs) is coming to an end, it is essential to disseminate the knowledge gained. For this reason, all authors of the IWA Scientific and Technical Report on benchmarking have come together to provide their insights, highlighting areas where knowledge may still be deficient and where new opportunities are emerging, and to propose potential avenues for future development and application of the general benchmarking framework and its associated tools. The paper focuses on the topics of temporal and spatial extension, process modifications within the WWTP, the realism of models, control strategy extensions and the potential for new evaluation tools within the existing benchmark system. We find that there are major opportunities for application within all of these areas, either from existing work already being done within the context of the benchmarking simulation models (BSMs) or applicable work in the wider literature. Of key importance is increasing capability, usability and transparency of the BSM package while avoiding unnecessary complexity.

Model-based knowledge acquisition in environmental decision support system for wastewater integrated management

The main goal of the Water Framework Directive is to achieve good chemical and ecological status of water bodies by 2015. The implementation of integrated river basin management, including sewer systems, wastewater treatment plants and receiving water bodies, is essential to accomplishing this objective. Integrated management is complex and therefore the implementation of control systems and the development of decision support systems are needed to facilitate the work of urban wastewater system (UWS) managers. Within this context, the objective of this paper is to apply integrated modelling of an UWS to simulate and analyse the behaviour of the 'Congost' UWS in Spain, and to optimize its performance against different types of perturbations. This analysis results in optimal operating set-points for each perturbation, improves river water quality, minimizes combined sewer overflows and optimizes flow lamination from storm water tanks. This is achieved by running Monte Carlo simulations and applying global sensitivity analysis. The set-points will become part of the knowledge base composed of a set of IF-THEN rules of the environmental decision support system being developed for this case study.

Including greenhouse gas emissions during benchmarking of wastewater treatment plant control strategies

The main objective of this paper is to demonstrate how greenhouse gas (GHG) emissions can be quantified during the evaluation of control strategies in wastewater treatment plants (WWTP). A modified version of the IWA Benchmark Simulation Model No 2 (BSM2G) is hereby used as a simulation case study. Thus, the traditional effluent quality index (EQI), operational cost index (OCI) and time in violation (TIV) used to evaluate control strategies in WWTP are complemented with a new dimension dealing with GHG emissions. The proposed approach is based on a set of comprehensive models that estimate all potential on-site and off-site sources of GHG emissions. The case study investigates the overall performance of several control strategies and demonstrates that substantial reductions in effluent pollution, operating costs and GHG emissions can be achieved when automatic control is implemented. Furthermore, the study is complemented with a scenario analysis that examines the role of i) the dissolved oxygen (DO) set-point, ii) the sludge retention time (SRT) and iii) the organic carbon/nitrogen ratio (COD/N) as promoters of GHG emissions. The results of this study show the potential mechanisms that promote the formation of CO2, CH4 and N2O when different operational strategies are implemented, the existing synergies and trade-offs amongst the EQI, the OCI and TIV criteria and finally the need to reach a compromise solution to achieve an optimal plant performance.

Congenital absence of the posterior arch of the atlas associated with a fracture of the anterior arch

Structural defects of the posterior arch of the atlas are rare, and range from clefts of variable location and size to more extensive defects such as complete agenesis. These abnormalities are usually incidental radiological findings. We present a case of a fracture of the anterior arch of the atlas associated with a congenital abnormality of the posterior arch.

A model for the simulation of the SHARON process: pH as a key factor

The SHARON process allows partial nitrification of wastewaters with high ammonium content and, when coupled with the Anammox process, represents a more sustainable alternative for N-removal than a conventional nitrification-denitrification. In this work, a mathematical model describing a continuously aerated SHARON reactor is presented. Special attention was given to the pH, because it affects substrates availability and inhibition phenomena, implementing an algorithm for its calculation. Since ammonium-oxidizing and nitrite-oxidizing organisms are inhibited by their own substrates, ammonia and nitrous acid respectively, Haldane kinetics was used in both nitrification steps. A preliminary evaluation of the model using historical experimental data generated in a lab-scale SHARON reactor, fed with synthetic substrate, is also presented, corroborating that the quality of the obtained effluent is highly dependent on pH.