The concentrations and behaviour of 105 different active pharmaceutical ingredients (APIs) in the aqueous phase of sewage water within a municipal sewer collection system have been investigated. ...Sewage water samples were gathered from seven pump stations (one of which was located within a university hospital) and from sewage water treatment influent and effluent. The targeted APIs were quantified using a multi-residue method based on online solid phase extraction liquid chromatography tandem mass spectrometry. The method was thoroughly validated and complies with EU regulations on sample handling, limits of quantification, quality control and selectivity. 51 APIs, including antibiotics, antidepressants, hypertension drugs, analgesics, NSAIDs and psycholeptics, were found frequently within the sewer collection system. API concentrations and mass flows were evaluated in terms of their frequency of detection, daily variation, median/minimum/maximum/average concentrations, demographic dissimilarities, removal efficiencies, and mass flow profiles relative to municipal sales data. Our results suggest that some APIs are removed from, or introduced to, the aqueous phase of sewage waters within the studied municipal collection system.
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•This study focuses on sewage water from a sewer collection system.•Active pharmaceutical ingredients were determined in the aqueous phase.•High antibiotic, analgesic, hypertension drug, and NSAID concentrations were found.•Certain APIs are removed from or introduced to the aqueous phase before treatment.
Modeling mass flows is classically based on the hydrostatic, depth-averaged balance equations. However, if the momentum transfers scale similarly in the slope parallel and the flow depth directions, ...then the gravity and the acceleration can have the same order of magnitude effects. This urges for a non-hydrostatic model formulation. Here, I extend existing single-phase Boussinesq-type gravity wave models by developing a new non-hydrostatic model for multi-phase mass flows consisting of the solid and fine-solid particles, and viscous fluid (Pudasaini and Mergili, 2019 1). The new model includes enhanced gravity and dispersion effects taking into account the interfacial momentum transfers due to the multi-phase nature of the mass flow. I outline the fundamentally new contributions in the non-hydrostatic Boussinesq-type multi-phase gravity waves emerging from the phase-interactions including buoyancy, drag, virtual mass and Newtonian as well as non-Newtonian viscous effects. So, this contribution presents a more general, well-structured framework of the multi-phase flows with enhanced gravity and dispersion effects, setting a foundation for a comprehensive simulation of such flows. I discuss some particular situations where the non-hydrostatic and dispersive effects are more pronounced for multi-phase mass flows. Even the reduced models demonstrate the importance of non-hydrostatic contributions for both the solid and fine-solid particles, and the viscous fluid. Analytical solutions are presented for some simple situations demonstrating how the new dispersive model can be reduced to non-dispersive motions, yet largely generalizing the existing non-dispersive models. I postulate a novel, spatially varying dissipative force, called the prime-force, which physically controls the dynamics, run-out and the deposition of the mass flow in a precise way. The practitioners and engineers may find this force very useful in relevant technical applications. This illuminates the need of formally including the prime-force in the momentum balance equation. A simple dispersion equation is derived. I highlight the essence of dispersion on the mass flow dynamics. Dispersion consistently produces a wavy velocity field about the reference state without dispersion. Emergence of such a dispersive wave is the first of this kind for the avalanching debris mass. It is revealed that the dispersion intensity increases energetically as the solid volume fraction or the friction decreases.
A huge amount of construction material is required in urban areas for developing and maintaining buildings and infrastructure. Ageing stocks, which were built during a period of rapid growth in Japan ...(1955-1973), will cause a new waste flow in the near future. In order to assess urban metabolism with regard to building and infrastructure, it is necessary to understand change in its material accumulation both 'spatially' and 'temporally'. In this analysis, material accumulation over time is elucidated using four-dimensional Geographical Information Systems (4d-GIS) data at an urban scale. An approximately 8 km
2
urban area of Salford in Manchester, UK, and 11 km
2
of Wakayama City centre, Japan, were selected as case study sites. In this analysis, the material stock of buildings, roadways and railways was estimated locally over time, using a 4d-GIS database: (1) to find the spatial distribution of construction materials over time, (2) to estimate the demolition curve of buildings based on characteristics of an area, and (3) to clarify material accumulation with vertical location, such as above and below ground, from the viewpoint of recyclability. By estimation of the demolition curve, the life span of buildings in an urban area was found to be shorter than the national average respectively at both sites: 81 years in the urban area of Salford compared with 128 years for the UK; and 28 years in Wakayama City centre compared with the Japanese national average of 40 years. In 2004, 47% of total construction material was stocked in underground infrastructure in Wakayama City centre.
Une quantité considérable de matériaux de construction est nécessaire dans les zones urbaines pour construire et entretenir les bâtiments et les infrastructures. Les parcs bâtis vieillissants, qui ont été construits au cours d'une période de croissance rapide au Japon (1955-1973) occasionneront un nouveau flux de déchets dans un proche avenir. Afin d'évaluer le métabolisme urbain du point de vue des bâtiments et des infrastructures, il est nécessaire de comprendre à la fois dans l'espace et dans le temps les changements intervenant dans son accumulation de matériaux. Dans cette analyse, l'accumulation de matériaux au fil du temps est élucidée en utilisant les données de Systèmes d'Information Géographique quadridimensionnels (SIG-4D) à une échelle urbaine. Un secteur urbain d'environ 8 km
2
de Salford, à Manchester, au Royaume-Uni, et 11 km
2
du centre-ville de Wakayama, au Japon, ont été sélectionnés comme sites pour cette étude de cas. Dans cette analyse, le parc de matériaux constitué par les bâtiments, les routes et les voies ferrées a été estimé localement au fil du temps, en utilisant une base de données SIG-4D: (1) pour découvrir la distribution spatiale des matériaux de construction au fil du temps, (2) pour estimer la courbe de démolition des bâtiments en se basant sur les caractéristiques d'un secteur, et (3) pour clarifier l'accumulation de matériaux par leur emplacement vertical, tel qu'au-dessus et en dessous du sol, du point de vue de la recyclabilité. Grâce à l'estimation de la courbe de démolition, il a été découvert que la durée de vie des bâtiments dans un secteur urbain est inférieure à la moyenne nationale sur les deux sites, respectivement: 81 ans dans le secteur urbain de Salford, comparé à 128 ans pour le Royaume-Uni; et 28 ans dans le centre-ville de Wakayama, comparé à la moyenne nationale japonaise de 40 ans. En 2004, 47% de la totalité des matériaux de construction, dans le centre-ville de Wakayama, étaient accumulés dans les infrastructures souterraines.
Mots clés: parc bâti, Systèmes d'Information Géographique quadridimensionnels (SIG-4D), parc des infrastructures, flux de masse, intensité en matériaux, analyse du parc de matériaux, développement durable, temps, flux de masse urbaine
The Molise and Apulia subsurface exploration has found clastic calcareous layers at the top of the Mesozoic—Miocene carbonate sequence and within the Middle Pliocene turbidites. The first are the ...result of Karst—fissures and crushing on the structural highs and mass flows at the base of fault slopes. Within the turbidites a biocalcarenitic horizon IS an electric good marker which proves an event of a shelf build up. It corresponds to the Middle Pliocene gap widely developed in the Apennines.
Ploughing is an erosion mechanism where the dam-like front of a geophysical flow shovels sediments along its path to increase its runout. Ploughing is commonly reported in the field. However, the ...physics of ploughing remain missing in hazard assessments tools owing to the difficulties of simulating the competing effects between erosion and deposition. In this study, 2D non-depth-averaged (non-DA) simulations are used to elucidate the physics of ploughing induced by erosion and deposition. A closure model for erosion and deposition is then developed and implemented into a depth-averaged (DA) framework to facilitate practical simulations for routine hazard assessments. Both the 2D non-DA and DA models are based on the Smoothed Particle Hydrodynamics (SPH) method. The new DA model is evaluated with experimental data and shown to be able to simulate the competing effects of erosion and deposition, which causes flow momentum gain and loss, respectively. The new DA framework is proven to be able to simulate the effects of ploughing, which has been a long-standing limitation of DA models.
Even though sulfur compounds and their transformations may strongly affect wastewater treatment processes, their importance in water resource recovery facilities (WRRF) operation remains quite ...unexplored, notably when it comes to full-scale and plant-wide characterization. This contribution presents a first-of-a-kind, plant-wide quantification of total sulfur mass flows for all water and sludge streams in a full-scale WRRF. Because of its important impact on (post-treatment) process operation, the gaseous emission of sulfur as hydrogen sulfide (H2S) was also included, thus enabling a comprehensive evaluation of sulfur flows. Data availability and quality were optimized by experimental design and data reconciliation, which were applied for the first time to total sulfur flows. Total sulfur flows were successfully balanced over individual process treatment units as well as the plant-wide system with only minor variation to their original values, confirming that total sulfur is a conservative quantity. The two-stage anaerobic digestion with intermediate thermal hydrolysis led to a decreased sulfur content of dewatered sludge (by 36%). Higher (gaseous) H2S emissions were observed in the second-stage digester (42% of total emission) than in the first one, suggesting an impact of thermal treatment on the production of H2S. While the majority of sulfur mass flow from the influent left the plant through the treated effluent (> 95%), the sulfur discharge through dewatered sludge and gaseous emissions are critical. The latter are indeed responsible for odour nuisance, lower biogas quality, SO2 emissions upon sludge combustion and corrosion effects.
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•Total sulfur flows were quantified plant-wide at a water resource recovery facility.•The added-value of experimental design and data reconciliation was demonstrated.•Most of the influent sulfur mass flow left the plant with the treated effluent.•The sulfur content of mixed sludge decreased by 36% during sludge treatment.•Most (gaseous) H2S was emitted during anaerobic digestion and primary thickening.
Smarter Smart District Heating Novitsky, Nikolay N.; Shalaginova, Zoya I.; Alekseev, Aleksandr A. ...
Proceedings of the IEEE,
09/2020, Letnik:
108, Številka:
9
Journal Article
Recenzirano
This article reviews modern district heating systems (DHS), with the main emphasis on the new challenges in modeling, operation, and planning. We give a brief historical overview of evolution of ...heating systems around the world and provide the description of DHS in the countries where they constitute a substantial component of the energy supply infrastructure. Main modeling approaches are then reviewed. The review is followed by discussion of the major challenges in modern DHS: active consumers, state estimation, control issues, and future challenges of the operation under uncertainties.
Gravitational mass movements may erode and/or entrain a significant amount of bed material that can strongly affect the flow dynamics until the moving mass eventually deposits and comes to rest. Snow ...avalanches generally release on slopes covered by a metastable and thus potentially erodible snow cover that can have a wide range of strength – or cohesion – depending on the type of snow and its physical properties. As the avalanche flows, the snow cover is fully or partially entrained at the front and at the base of the flow, increasing the mass of the avalanche. Conversely, at the tail, snow may be deposited along the track, reducing the overall flowing mass. The balance between entrainment and deposition therefore determines the growing or decaying of the avalanche in terms of mass. To date, it remains unclear how cohesion influences these processes and what consequences it has for avalanche dynamics and run-out. Here, we perform simulations based on the Discrete Element Method (DEM) to analyze the influence of cohesion and slope angle on the erosion, entrainment, mixing and deposition processes. This method makes it possible to follow the dynamics of the particles within the flow very precisely, something that cannot be done in real experiments. In the model, the cohesion is represented as the combined effects of a fragmentation potential associated with the strength of the bonds, and an aggregation potential associated with the stickiness of the particles. For various combinations of input parameters and material properties, we release a heap of particles over an erodible bed and simulate the entrainment and deposition mechanisms. Our results show on the one hand that a low strength (< 3 kPa) promotes a ploughing entrainment mechanism and a large entrainment velocity, up to 3 m/s. On the other hand a high strength (> 3 kPa) favors basal abrasion as the flow front is not able to destabilize the erodible bed at once. In this case, the entrainment velocity decreases typically below 1 m/s. This has important consequences on mixing: the front in granular flows with low strength and adhesion is typically made of freshly entrained material coming from the whole depth of the bed, while remains of the released material can be found at the front of highly cohesive avalanches. Finally, the deposition process is analyzed by evaluating the relationship between the deposit thickness hstop and slope angle θ which extends the framework of the model of hstopθ from cohesionless to cohesive granular flows. We find that a higher bond strength of the flowing material increases the deposition height. Our work improves our understanding of the mechanics of cohesive granular flows and may contribute to improving parameterizations in depth-averaged models used to simulate geophysical mass flows such as rock, ice, snow avalanches, debris flows and landslides.
•Low granular cohesion favors entrainment by ploughing and fast entrainment velocities.•High cohesion promotes basal abrasion with entrainment velocities below 1 m/s.•The front of cohesionless flows is mainly made of freshly entrained material.•Material from the release zone can be found at the front of cohesive flows.•The deposition height at the tail of the avalanche increases with cohesion.
When gravitational mass flows hit water bodies, they create water waves, called tsunami. The slopes of the mountain flanks surrounding a glacial lake or the slopes of the side walls of artificially ...constructed reservoirs play important roles in the intensity of splash on landslide impact, amplitudes and propagation speeds of the resulting water waves and possible dam breaching or overspilling of water. The proper analyses of such dynamics are useful for the possible mitigation measures. Here, we apply a general two-phase mass flow model to perform several numerical experiments and present geometrically three-dimensional, high-resolution simulation results for rapidly moving two-phase landslide/debris flow down a plane with varying slopes at its different parts, impacting a fluid reservoir. First, the upstream slope is kept constant; later to make it closer to reality, sudden changes in slopes are imposed one after another at different parts of the topography. The results focus on the effects of the sudden slope changes in the formation and propagation of dynamically different solid- and fluid wave-structures in the reservoir. Results show that steeper upper part of the topography produces more highly intensified tsunami that propagates more longitudinally than the steeper lower part. Thus, steeper upper parts need stronger right coast and steeper lower parts demand stronger side walls in mountain reservoirs to withstand the wave impacts. The results may help for the proper modeling of landslide and debris induced mountain tsunamis in rapidly changing slopes, the dynamics of turbidity currents and sediment transports in fluid reservoirs in high mountain slopes.
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