1,448 research outputs found
Infiltration and inflow to wastewater sewer systems - A literature review on risk management and decision support
Wastewater sewer systems are one of our largest infrastructural assets. By transporting the sewage from our homes and other facilities to the wastewater treatment plants, the sewer systems protect public health, properties, and the environment. However, in addition to the sanitary sewage, there is an infiltration and inflow (I/I) of other water to the sewer system. This additional load can result in adverse effects such as basement flooding, combined sewer overflows, and larger pumping and treatment costs. I/I can originate from rainfall but also from sources such as groundwater, surface water or leaking drinking water pipes. Expected climate change effects include more intense rain events and periods of higher water levels which will increase the problem of I/I. Hence, it is important to manage I/I in a proper way by implementing efficient measures that provide the largest societal gain from a sustainability point of view.This literature review was performed to form a basis for research on developing risk-based decision support models to evaluate I/I in wastewater sewer systems from a system perspective and with focus on sustainability. It reviews publications on I/I focusing on sources, impacts, quantification and mitigation measures, addresses risk definitions, and the risk management process. Further, common decision support methods are described and literature on decision support models to evaluate I/I are reviewed. Important conclusions are that a vast amount of literature exists on finding and reducing I/I from a technical point of view and in several publications different decision support models are used to evaluate measures aiming at reducing I/I. However, existing models are focused on project internal and financial aspects and a need for future studies is identified, evaluating I/I from a broader societal and sustainability perspective, including project external, environmental, and social criteria
Index to 1986 NASA Tech Briefs, volume 11, numbers 1-4
Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1986 Tech Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences
Sustainable Management of Urban Water Resources
It is well known that 55% of the world’s population currently lives in urban areas, and this figure is predicted to grow to 68% by 2050, adding more than 2.5 billion people to urban populations. It is also projected that there will be 43 megacities worldwide by 2030, with populations of more than 10 million inhabitants. The United Nations World Water Development Report, 2018, warned that by 2030, the global demand for fresh water is likely to exceed supply by 40%. Added to population growth, climate change has the potential to lead to changes in rainfall regimes, with the potential of increased flooding and drought. Currently, 1.2 billion people are at risk from flooding, but this is predicted to increase to about 1.6 billion, i.e., nearly 20% of the total world population, by 2050. In line with this, replacing deteriorating water management infrastructure that can no longer cope is economically unfeasible, impracticable from a construction point of view, and likely to fail in the long term. To address these issues, approaches are needed that are flexible and have multiple benefits. In its World Water Development Report, 2018, the UN promotes the use of nature-based solutions to some of these problems, with the focus of Sustainable Development Goal 6 (making sure that everyone has access to a safe and affordable supply of potable water and sanitation by 2030) requiring investment in suitable infrastructure across the world. This Special Issue covers the challenges faced in managing urban water in all its forms, from potable supplies to reuse and harvesting, as well as resilient and sustainable approaches developed to address flooding and drought
NASA Tech Briefs, February 1987
Topics include: NASA TU Services; New Product Ideas; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Fabrication Technology; Machinery; Mathematics and Information Sciences; Life Sciences
Implementing Nature-based Solutions and Green Infrastructure for Cities, Citizens and Rivers - The SEE-URBAN-WATER Project
Cities and their rivers are undergoing significant transformations owing to the impact of multiples challenges at a time such as rapid population growth, infrastructure development, and climate change. The consequences are evident in increased flood risks, groundwater pollution, accelerated soil erosion, drinking water scarcity, green space depletion, and biodiversity loss. In light of this, interest in novel concepts such as Nature-Based Solutions (NbS) is growing, extending beyond academia to influence micro-, meso-, and macro-urban scales.
Motivated by the potential of NbS to deliver social, ecological, and societal benefits, the SEE-URBAN-WATER (SUW) research group aimed to provide a robust knowledge and methodological basis for achieving socio-ecological transformation through the inter- and transdisciplinary planning, design, and implementation of NbS and Green Infrastructures in highly urbanized areas susceptible to environmental and climate risks.
From 2018 to 2023, SUW, funded within the framework of the Research for Sustainability program (known by its German acronym FONA) by the German Federal Ministry of Education and Research (abbreviated to BMBF in German), produced numerous master’s and doctoral theses, methodological frameworks, scientific publications, and technical guidelines. Nevertheless, this book goes beyond being a mere compendium of these outcomes; it clearly illustrates the systematic inter- and transdisciplinary evolution and interconnection of ideas for building more socially and environmentally resilient cities
Ecological Stormwater Management: Analysis of design components to improve understanding and performance of stormwater retention ponds
Stormwater runoff from developed land is a source of pollution and excessive flow to waterways. The most commonly employed practices for flow and volume control are stormwater ponds and basins (also referred to as detention and retention ponds). These structures can be effective at controlling peak discharge to water bodies by managing flow timing but are often ineffective at removing nutrients, particularly in dissolved forms. Pond morphology coupled with place-specific characteristics (like soil type and drainage area characteristics) may influence plant community composition in these water bodies. The interaction of physical, chemical, and biological elements in stormwater ponds may affect their water quality performance in more significant ways than previously understood. Floating treatment wetlands (FTW) are floating rafts of vegetation that can be constructed using a variety of materials and are an emerging technology aimed at improving the pollutant removal and temperature control functions of stormwater ponds. Previous studies with field research in subtropical and semiarid climatic regions found incremental nutrient removal improvement correlated with FTW coverage of pond surface area. However, data on their performance in cold climates is lacking from the literature.
This dissertation presents data from a three-year study examining the performance of FTW on stormwater pond treatment potential in cold climate conditions and optimal vegetation selection based on biomass production, phosphorus (P) uptake, and root architectural characteristics that enhance entrapment functionality. To put the FTW pond performance data into context, results from a survey of seven permitted stormwater ponds in Chittenden County, Vermont and the ponds\u27 associated variability in influential internal and external dynamics are also discussed. Pond morphology, drainage area land use, soil types, and biological communities are analyzed for correlative relationships to identify design factors that affect pond performance but are not controlled factors in stormwater system permitting
Recommended from our members
Design of equipment safety & reliability for an aseptic liquid food packaging line through maintenance engineering
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The organisation of maintenance, in the Aseptic Liquid Food (ALF) industry, represents an important management task that enables a company to pursue higher manufacturing effectiveness and improved market share. This research is concerned with the process to design and implement maintenance tasks. These two complementary processes (design and implementation) have been thought and designed to answer the particular needs of food industry regarding product safety and equipment reliability.
Numerous maintenance engineering researchers have focused on maintenance engineering and reliability techniques highlighting the contribution of maintenance in achieving world class manufacturing and competitive advantage. Their outcome emphasizes that maintenance is not a “necessary evil” because of costs associated, but it can be considered an “investment” that produces an added value which generates a real company profit. The existing maintenance engineering techniques pursue equipment reliability at minimum cost; but in food industry, food safety represents the most critical issue to address and solve.
The research methodology chosen is based on case studies coming from ALF industries. These show that low maintenance effectiveness could have dramatic effects on final consumers and on the company’s image and underline the need of a maintenance design and implementation process that takes into consideration all critical factors relevant to liquid food industry. The analysis of measurable indicators available, represents a tool necessary to show the status of critical performance indicators and reveals the urgency of a research necessary to address and solve the maintenance problems in food industry.
The literature review underlines the increasing regulations in place in food industry and that no literature is available to define a maintenance design and implementation process for ALF and in general for food industry. The literature review enabled also the gap existing between theory and real maintenance status, in the ALF, to be identified and the aim of the research was to explore this gap. The analysis of case studies and Key Performance Indicators (KPI’s) available highlights the problem and the literature review provides the knowledge necessary to identify the process to design and implement maintenance procedures for ALF industry.
The research findings provide a useful guide to identify the process to design maintenance tasks able to put under control food safety and equipment reliability issues. Company’s restraining forces and cultural inertia, that work against new maintenance procedures, have been analysed and a maintenance implementation process have been designed to avoid losing the benefits produced by the design phase. The analysis of condition monitoring systems shows devices and techniques useful to improve product safety, equipment reliability, and then maintenance effectiveness.
This research aimed to fill the gap in the existing literature showing the solution to manage both food safety and production effectiveness issues in food industry. It identifies a maintenance design process able to capture all conceivable critical factors in food industry and to provide the solution to design reliable task lists. Furthermore, the maintenance implementation process shows the way to maximize the maintenance design outcome through the empowerment of equipment operators and close cooperation with maintenance and quality specialists. The new maintenance design and implementation process represents the answer to the research problem and a reliable solution that allows the food industry to improve food safety and production effectiveness
Spatial modeling and visualization of habitat response to hydrologic restoration in New England salt marshes
Anthropogenic alterations that restrict tidal flows negatively impact 20% of New England salt marshes, but management attempts to restore tides to these sites can be met with unexpected or less than optimal results. Restoration planners may be hindered by a lack of synthesized information regarding important biotic and abiotic factors that determine the distribution of dominant salt marsh plants and invasive species. An ecosystem model was developed to better predict salt marsh habitat response to hydrologic modification as a synthesis of existing models for biomass production, marsh elevation, tidal hydrology, and plant succession. A field experiment was conducted to provide the ecological basis for estimating plant responses to physical stresses and interspecific competition. Six plant species common to New England salt marshes were examined: halophyte species Spartina alterniflora, Spartina patens, and Juncus gerardii, and brackish invasive species Phragmites austrahs, Typha angustifolia, and Lythrum salicaria .
The model was applied to spatial grids representing marsh area at four salt marsh sites with past or current impacts due to restricted tidal flows. At each site, field data for model parameterization was acquired according to a regional data-collection protocol. To assess model performance, the spatial distribution of marsh plants was predicted using specifications from past hydrologic and ecological conditions at two sites. Aggregated model predictions of halophyte-dominated and invasive-dominated marsh areas were within 4% of observed totals. The model was then run for each of the four study sites to generate 20-year simulations of plant composition changes resulting from current and possible hydrologic scenarios. Scenarios included changes in culvert shape, dimensions, and placement. Model simulations in response to tidally-restricted conditions predicted gradual replacement of halophytes by brackish invasive species, especially P. australis. Simulations involving tidal restoration strongly favored halophyte species. Based on spatial model outputs, realistic visualizations of marsh scenario results were designed and rendered. Use of this technology may provide new ways for resource managers to assess potential restoration outcomes, and to communicate the expected results of marsh improvement projects to non-technical audiences
- …