Rosette Diffusers for Dense Effluents

Abessi, Ozeair; Roberts, Philip J. W.; Gandhi, Varun

doi:10.1061/(asce)hy.1943-7900.0001268

Cited by 14 publications

(7 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Offshore discharge by diffuser systems includes various configurations, such as single nozzle, multiport, or rosette diffusers. ,, These diffuser systems distribute the brine further away from the coastline (up to a few km) and at greater depths (∼20 m) to avoid potential impacts on sensitive shallower coastal habitats and enhance the mixing with offshore currents ,, (Figure ). Outfall systems that utilize rosette or multiport diffusers have numerous nozzles (4–12), which are oriented in the direction of the prevailing currents (angled generally from 30–60°) to maximize the dilution. , However, it was reported that in some occasions, diffuser systems can affect an area as large as 13 km 2 around the discharge point in which the salinity of the brine plume that gravimetrically spreads downslope along the sea bottom is ≥1% above the ambient. ,,,,, Although the impacted area can be larger than that of the direct discharge, it has been shown that using a diffuser system can enhance the brine dilution efficiency and reduce the environmental impact. ,,,,, …”

Section: Resultsmentioning

confidence: 99%

Impacts of Desalination Brine Discharge on Benthic Ecosystems

Sirota,

Winters,

Levy

et al. 2024

Environ. Sci. Technol.

View full text Add to dashboard Cite

Seawater reverse osmosis (SWRO) desalination facilities produce freshwater and, at the same time, discharge hypersaline brine that often includes various chemical additives such as antiscalants and coagulants. This dense brine can sink to the sea bottom and creep over the seabed, reaching up to 5 km from the discharge point. Previous reviews have discussed the effects of SWRO desalination brine on various marine ecosystems, yet little attention has been paid to the impacts on benthic habitats. This review comprehensibly discusses the effects of SWRO brine discharge on marine benthic fauna and flora. We review previous studies that indicated a suite of impacts by SWRO brine on benthic organisms, including bacteria, seagrasses, polychaetes, and corals. The effects within the discharge mixing zones range from impaired activities and morphological deformations to changes in the community composition. Recent modeling work demonstrated that brine could spread over the seabed, beyond the mixing zone, for up to several tens of kilometers and impair nutrient fluxes from the sediment to the water column. We also provide a possible perspective on brine's impact on the biogeochemical process within the mixing zone subsurface. Desalination brine can infiltrate into the sandy bottom around the discharge area due to gravity currents. Accumulation of brine and associated chemical additives, such as polyphosphonate-based antiscalants and ferric-based coagulants in the porewater, may change the redox zones and, hence, impact biogeochemical processes in sediments. With the demand for drinking water escalating worldwide, the volumes of brine discharge are predicted to triple during the current century. Future efforts should focus on the development and operation of viable technologies to minimize the volumes of brine discharged into marine environments, along with a change to environmentally friendly additives. However, the application of these technologies should be partly subsidized by governmental stakeholders to safeguard coastal ecosystems around desalination facilities.

show abstract

Section: Resultsmentioning

confidence: 99%

Impacts of Desalination Brine Discharge on Benthic Ecosystems

Sirota,

Winters,

Levy

et al. 2024

Environ. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…A key factor influencing the mixing processes of effluents is the diffuser type. In recent decades, rosette-type multiport diffusers have become popular due to their merits of being cheaper and less space-demanding than traditional diffusers (e.g., single-port diffusers) [7][8][9]. However, because of the complex mechanisms, the practice of modeling the mixing processes of rosette-type multiport diffusers has not yet been well established and requires further investigation.…”

Section: Introductionmentioning

confidence: 99%

“…In recent years, complementing the experimental studies [8][9][10][11][12], the simulation of the mixing processes of jets and plumes using fully physics-based computational fluid dynamics models has become popular because of the improvements in computing capabilities [13][14][15][16][17][18]. One shortcoming of the CFD approach is that it typically requires heavy computing resources and long simulation time, and it is thus helpful to propose a new technique that can make predictions faster with lower requirements for computing resources.…”

Section: Introductionmentioning

confidence: 99%

Simulations of the Concentration Fields of Rosette-Type Multiport Buoyant Discharges Using Combined CFD and Multigene Genetic Programming Techniques

Yan

Wang

Mohammadian

et al. 2021

JMSE

View full text Add to dashboard Cite

Rosette-type diffusers are becoming popular nowadays for discharging wastewater effluents. Effluents are known as buoyant jets if they have a lower density than the receiving water, and they are often used for municipal and desalination purposes. These buoyant effluents discharged from rosette-type diffusers are known as rosette-type multiport buoyant discharges. Investigating the mixing properties of these effluents is important for environmental impact assessment and optimal design of the diffusers. Due to the complex mixing and interacting processes, most of the traditional simple methods for studying free single jets become invalid for rosette-type multiport buoyant discharges. Three-dimensional computational fluid dynamics (3D CFD) techniques can satisfactorily model the concentration fields of rosette-type multiport buoyant discharges, but these techniques are typically computationally expensive. In this study, a new technique of simulating rosette-type multiport buoyant discharges using combined 3D CFD and multigene genetic programming (MGGP) techniques is developed. Modeling the concentration fields of rosette-type multiport buoyant discharges using the proposed approach has rarely been reported previously. A validated numerical model is used to carry out extensive simulations, and the generated dataset is used to train and test MGGP-based models. The study demonstrates that the proposed method can provide reasonable predictions and can significantly improve the prediction efficiency.

show abstract

“…However, the spacing and funds are often limited in practical engineering projects, so it is becoming a common practice to use diffusers with multiple ports [8,9]. Depending on how the ports are configured, a multiport diffuser can be classified into different types, such as unidirectional [9,10], Tee-shaped [11], and rosette-shaped [12,13]. Rosette-type multiport diffusers are becoming popular nowadays.…”

Section: Introductionmentioning

confidence: 99%

“…The buoyant jets discharged from a rosette-type diffuser are Physical modeling and experimental approaches are currently the most common ways of studying rosette jets (Table 1). For example, Lai and Lee [14] published the measured trajectories of the jets discharged from rosette-shaped diffusers to stagnant water, Abessi et al [12] measured the mixing processes of rosette dense jets in stationary receiving water, and Abessi and Roberts [13] reported the measurements of the concentration fields for rosette dense jets in flowing currents. These previous experimental works have significantly advanced the knowledge of rosette jets.…”

Section: Introductionmentioning

confidence: 99%

Three-Dimensional Numerical Simulations of Buoyant Jets Discharged from a Rosette-Type Multiport Diffuser

Yan

Mohammadian

Chen

2019

JMSE

View full text Add to dashboard Cite

In some outfall systems, wastewaters are discharged into ambient water bodies using rosette-type diffusers in the form of multiple buoyant jets, and it is essential to simulate their mixing characteristics for practical applications and optimal design purposes. The mixing processes of a rosette jet group are more complicated than single jets and multiple horizontal or vertical jets, and thus the existing methods cannot be effectively used to simulate their mixing and dilution properties. With the recent advancements in numerical modeling approaches, numerical simulation of wastewater jets as three-dimensional phenomena can be feasible. The present study deals with a fully three-dimensional numerical simulation for buoyant jets discharged from a rosette-type multiport diffuser, with the standard and re-normalization group (RNG) k-ε turbulence models. The simulated results are compared with experimental data, and the results show a good agreement with the experimental data, demonstrating that the numerical model is an efficient and effective tool for simulating rosette jet groups. It was also concluded that the RNG k-ε model leads to better results than the standard k-ε model with a comparable computational cost. The validated model was further utilized to investigate the influences of port inclinations on the mixing behaviors.

show abstract

Rosette Diffusers for Dense Effluents

Cited by 14 publications

References 12 publications

Impacts of Desalination Brine Discharge on Benthic Ecosystems

Impacts of Desalination Brine Discharge on Benthic Ecosystems

Simulations of the Concentration Fields of Rosette-Type Multiport Buoyant Discharges Using Combined CFD and Multigene Genetic Programming Techniques

Three-Dimensional Numerical Simulations of Buoyant Jets Discharged from a Rosette-Type Multiport Diffuser

Contact Info

Product

Resources

About