Multiphase Numerical Modelling of Hydraulic Structures With Rapidly Rotating Flows: Stormwater Vortex Hydrodynamic Separator

Hydraulic structures exhibiting strongly rotating flows are widely applied in the field of urban and wastewater hydraulics. Given demographic, urban development and climate change challenge, such infrastructure will require significant design innovation. Computational fluid dynamics (CFD) is increasingly an effective and widely used tool to evaluate and optimise new designs and determine performance efficiency for such structures. In this study, a full-scale prototype of a hydrodynamic vortex grit interceptor for stormwater conveyance systems (the BMS Stormbreaker Defender) was investigated using experimental and numerical methods. The prototype was evaluated physically in a full-scale test rig permitting flows of up to 30 l/s. Three-dimensional velocity distributions were obtained along radial profiles using acoustic Doppler velocimetry (ADV). The three-dimensional flow field in the chamber were also modelled using the ANSYS CFX software with a multiphase homogeneous Eulerian-Eulerian approach. In particular, the effectiveness of two-phase flow modelling using the shear stress transport (SST) model with curvature correction was analysed. Good qualitative and quantitative agreements were found between the numerical solutions and the experimental data sets for the four flow scenarios investigated. The results of the CFD evaluation/validation, the practicality of obtained data, and the implications for the design of such a structure are discussed

Design and implementation of a resource consumption benchmarking system for wastewater treatment plants

Energy and water are inextricably linked, and together they are the two of the most valuable global resources. Internationally, the links between the energy, wastewater and water sectors are attracting increasing attention. In the wastewater sector, pressures including increasingly stringent environmental regulations and greater volumes of wastewater being produced and treated are a major challenge. These challenges mean that, without intervention, wastewater treatment facilities will become more resource intensive and may increasingly exceed environmental requirements, such as discharge limits. These issues are set against the backdrop, in many countries, of an emphasis on cost reduction and increased concerns regarding sustainability of the sector. Thus it is imperative that tools and methodologies are developed that allow the wastewater sector to measure resource efficiency, benchmark its performance in a standardised and efficient manner and identify cost-effective measures that can improve plant performance. This research presents a novel resource benchmarking system for wastewater treatment plants (WWTPs). This toolkit is designed to be easily implemented and effective in enabling benchmarking of WWTPs with varying capacity, technology, sampling frequency and management practices. The research considers both centralised and decentralised facilities (manned and unmanned) and investigates the challenges of benchmarking plants where routine monitoring is sporadic

Bacterial inactivation, photoreactivation and dark repair post flow-through pulsed UV disinfection

Pulsed UV (PUV) technology is accepted commercially for disinfection within the food packaging industry, but has yet to be deployed by the water/wastewater sector. This is partly due to a lack of robust, independently validated data for submerged or flow-through treatment applications. This study evaluated the efficacy of PUV for water disinfection under flow-through conditions. Bacterial pathogens of interest in the food and water/wastewater sector, namely Escherichia coli, Staphylococcus aureus and Listeria innocua (surrogate for L. monocytogenes) were used to investigate the potential for photoreactivation and/or dark repair post PUV flow-through disinfection. A continuous-flow low-pressure UV was also analysed under similar experimental conditions. Bacterial inactivation via flow-through PUV was dependant on energy output with E. coli exhibiting greatest sensitivity to PUV treatment (5.3 log 10 inactivation after treatment at 1539 mJ/cm 2 - output in UV range < 300 nm); L. innocua exhibited the highest PUV resistance (3.0 log 10 inactivation after treatment at 1539 mJ/cm 2 – output in UV range < 300 nm) under similar treatment conditions. Greater photoreactivation occurred at lower PUV outputs for both S. aureus and E. coli after flow-through PUV treatment. Thus exposure of treated bacteria to natural light, immediately post flow-through PUV treatment, should be avoided to minimise photoreactivation. The LPUV demonstrated inactivation of all bacteria below the limit of detection (1 CFU/mL) and inhibited the occurrence of photoreactivation. This study highlights the importance of considering bacterial repair potential and the need for further development of PUV technology for such applicationsThe authors would like to acknowledge the Department of Agriculture, Food and the Marine of Ireland (Ref: 13-F-507) for funding this research. Dr. Val del Rio was supported by the Spanish Government (CTM2014-55397-JIN project co-funded by FEDER) and Xunta de Galicia postdoctoral fellowshipS

Opportunities for process control optimisation in Irish municipal wastewater treatment plants

As societies ever increasing reliance on electrical energy continues, the role of process optimisation becomes more and more prevalent. This paper presents an energy audit of a typical Irish wastewater treatment plant (P.E. 30,000 ) and attempts to investigate measures to increase the energy efficiencies within treatment plants across Ireland. Based on an in depth review of international energy efficient wastewater treatment plants, energy savings opportunities exist via the use of variable frequency drives to control pumps and blowers; the introduction of inter-basin dissolved oxygen control systems to provide the varying, relevant oxygen requirements to the aeration basin; and effective plant management using appropriate control strategies via accurate sensor feedback and real-time, online monitoring

Use of industrial by-products and natural media to adsorb nutrients, metals and organic carbon from drinking water

• The use of waste media in the water sector results in a robust, sustainable option. • Fly ash and Bayer residue successfully adsorb TOC, nutrients and Cu. • Granular blast furnace slag and pyritic fill have good adsorption potential. • pH adjustment is not necessary for optimal adsorption of contaminants. • Kinetic studies show that at least 60% of adsorption had taken place after 8 h. a b s t r a c t a r t i c l e i n f o Filtration technology is well established in the water sector but is limited by inability to remove targeted contaminants, found in surface and groundwater, which can be damaging to human health. This study optimises the design of filters by examining the efficacy of seven media (fly ash, bottom ash, Bayer residue, granular blast furnace slag (GBS), pyritic fill, granular activated carbon (GAC) and zeolite), to adsorb nitrate, ammonium, total organic carbon (TOC), aluminium, copper (Cu) and phosphorus. Each medium and contaminant was modelled to a Langmuir, Freundlich or Temkin adsorption isotherm, and the impact of pH and temperature (ranging from 10°C to 29°C) on their performance was quantified. As retention time within water filters is important in contaminant removal, kinetic studies were carried out to observe the adsorption behaviour over a 24 h period. Fly ash and Bayer residue had good TOC, nutrient and Cu adsorption capacity. Granular blast furnace slag and pyritic fill, previously un-investigated in water treatment, showed adsorption potential for all contaminants. In general, pH or temperature adjustment was not necessary to achieve effective adsorption. Kinetic studies showed that at least 60% of adsorption had occurred after 8 h for all media. These media show potential for use in a multifunctional water treatment unit for the targeted treatment of specific contaminants

Life cycle assessment of waste water treatment plants in Ireland

The European Water Act 91/271/EEC introduced a series of measures for the purpose of protecting the environment from the adverse effects of effluent discharge from Waste Water Treatment Plants (WWTP). There are environmental costs associated with attaining the required level of water quality set out in the act such as, emissions from energy production, ecotoxicity from sludge application to land. The goal of this study is to assess these costs. Life Cycle Assessment (LCA) has been the analytical tool used to evaluate the environmental loadings. The CML 2001 Life Cycle Impact Assessment (LCIA) methodology has been adopted and implemented using GaBi 6.0 LCA software. Two plants of varying size and location were chosen for the study. The study found that energy consumption and sludge application to land are the largest contributors to the environmental impact associated with waste water treatment

Digital transformation of peatland eco-innovations (‘Paludiculture’): Enabling a paradigm shift towards the real-time sustainable production of ‘green-friendly’ products and services

The world is heading in the wrong direction on carbon emissions where we are not on track to limit global warming to 1.5 degrees C; Ireland is among the countries where overall emissions have continued to rise. The development of wettable peatland products and services (termed 'Paludiculture') present significant opportunities for enabling a transition away from peat-harvesting (fossil fuels) to developing 'green' eco-innovations. However, this must be balanced with sustainable carbon sequestration and environmental protection. This complex transition from 'brown to green' must be met in real time by enabling digital technologies across the full value chain. This will potentially necessitate creation of new green-business models with the potential to support disruptive innovation. This timely paper describes digital transformation of paludiculture-based eco-innovation that will potentially lead to a paradigm shift towards using smart digital technologies to address efficiency of products and services along with future-proofing for climate change. Digital transform of paludiculture also aligns with the 'Industry 5.0 -a human-centric solution'. However, companies supporting peatland innovation may lack necessary standards, data-sharing or capabilities that can also affect viable business model propositions that can jeopardize economic, political and social sustainability. Digital solutions may reduce costs, increase productivity, improve produce develop, and achieve faster time to market for paludiculture. Digitisation also enables information systems to be open, interoperable, and user-friendly. This constitutes the first study to describe the digital transformation of paludiculture, both vertically and horizontally, in order to inform sustainability that includes process automation via AI, machine learning, IoT-Cloud informed sensors and robotics, virtual and augmented reality, and blockchain for cyber-physical systems. Thus, the aim of this paper is to describe the applicability of digital transformation to actualize the benefits and opportunities of paludiculture activities and enterprises in the Irish midlands with a global orientation.info:eu-repo/semantics/publishedVersio

The evaluation of technologies for small, new design wastewater treatment systems

Life cycle costing of small wastewater treatment systems can often be generic and lack a degree of detail that could affect the choice of system. Critical factors such as variations in loading, location and discharge limits are sometimes not given the required weight of importance, and as a result the most suitable, most economical system may not always be implemented. A decision support tool for small, new design wastewater treatment plants has been developed that accounts for variations in several parameters such as scale, discharge limits and sludge disposal. Capital and operational costs have been combined to produce life cycle models for six treatment systems. Each system was assessed in a number of scenarios with variations in scale, discharge limits and sludge disposal route. The results show that in most scenarios, constructed wetlands represent the most economical option where surface area is not restricted. For each system, the percentage contribution of labour to the total operational cost increases as agglomeration size is reduced

Life cycle assessment of wastewater treatment plants in Ireland

The Urban Wastewater Treatment Directive 91/271/EEC introduced a series of measures for the purpose of protecting the environment from the adverse effects of effluent discharge from wastewater treatment plants. There are environmental costs associated with attaining the required level of water quality set out in the directive such as greenhouse gas emissions due to energy production, and ecotoxicity from sludge application to land. The goal of this study is to assess the environmental costs in an Irish context, focusing specifically on the effects of variation in scale and discharge limitation. Life cycle assessment is the analytical tool used to evaluate the environmental impact. The life cycle impact assessment methodology developed by the Centre of Environmental Science, Leiden University (2010) has been adopted and implemented using GaBi 6.0 life cycle assessment software. Two plants of varying size and location were chosen for the study. The study found that energy consumption and sludge application to land are the largest contributors to the overall environmental impact associated with the treatment process at both plants. Economies of scale were observed in energy usage during secondary aeration