Analysis of sedimentation and resuspension processes of aquaculture biosolids using an oscillating grid

Masaló, Ingrid; Guadayol, Òscar; Peters, Francesc; Oca, Joan

doi:10.1016/j.aquaeng.2008.01.004

Cited by 8 publications

(6 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…For example, fecal particulates sink much more slowly than food pellets, partly because fecal particulates tend to absorb water and disintegrate, and thus reduce their density and settling velocity when descending through the water column [56,62]. Flow turbulence is also critical to settling as it breaks particles into smaller ones and maintain them longer in suspension and thus need more time to settle [63]; however, its precise effect is still poorly understood at present. Moreover, environmental conditions such as the seawater temperature and salinity affect water viscosity and thus have indirect impacts on particulate settling velocities.…”

Section: Concepts Of Regulatory Mixing Zonesmentioning

confidence: 99%

“…Specifically, smooth substrates typically require lower critical stresses for material resuspension than rough surfaces [75], while the critical shear stress also varies greatly among different particulate materials with varying size and cohesiveness. For instance, smaller-sized particulates tend to have lower resuspension thresholds, and resistance to resuspension increases with increasing cohesiveness, consolidation and biostabilization of the benthic sediment layer [63,76]. Moreover, numerical simulations have demonstrated that water depth also has a significant influence on the occurrence of particulate resuspension.…”

Section: Transport and Transformation Processes At The Seabed Sedimentsmentioning

confidence: 99%

See 1 more Smart Citation

A Review on Mariculture Effluent: Characterization and Management Tools

Wang

Cuthbertson

Gualtieri

et al. 2020

Water

View full text Add to dashboard Cite

While marine aquaculture, or mariculture, has been growing rapidly and globally in recent decades, many environmental concerns remain to be fully addressed to achieve its long-term goal of sustainable development. This paper aims to provide a synthesized perspective on these issues by reviewing and discussing the characterization, transport, and current modelling and management tools associated with effluents released from mariculture sites. Specifically, we examined the effluent characteristics and behavior from source-to-sink, including the composition and load of effluent discharge, its transport and transformation processes in the water column and at the seabed, and its impacts on the pelagic and benthic environments. We then focused on management-related issues, including the setting of the regulatory mixing zone, the establishment of environmental standards, monitoring measures, and modelling techniques to depict the current state-of-the-art modes in a global context. Our study shows that while substantial progress has been made in understanding the nature of the mariculture effluent, as well as in monitoring and modelling its transport and fate, the regulatory framework still lags behind in many countries where the mariculture industry is relevant. This is particularly evident in the lack of consistent criteria for the definition of regulatory mixing zones and the associated environmental standards for water quality and benthic impacts. Besides, as new predictive models are emerging quickly, their proper evaluation and validation are imperative in view of their increasing application in regulatory practices. This review is intended to provide references for advancing regulatory management of mariculture effluents, as well as for promoting sustainable mariculture development.

show abstract

Section: Concepts Of Regulatory Mixing Zonesmentioning

confidence: 99%

Section: Transport and Transformation Processes At The Seabed Sedimentsmentioning

confidence: 99%

A Review on Mariculture Effluent: Characterization and Management Tools

Wang

Cuthbertson

Gualtieri

et al. 2020

Water

View full text Add to dashboard Cite

show abstract

“…When cooled, the crucibles were reweighed. Sediments were then heated to 500°C (Loh 2005) for 16 h and weighed again when cool. Organic matter percentage was computed from data provided within the LOI methodology (Mudroch & Azcue 1995).…”

Section: Grab Samplesmentioning

confidence: 99%

Parameterising resuspension in aquaculture waste deposition modelling

Adams

Black²,

Black

et al. 2020

Aquacult. Environ. Interact.

View full text Add to dashboard Cite

Sustainable expansion of global aquaculture depends on a thorough understanding of environmental impacts. Open-water culture operations produce waste food and faeces, the benthic impacts of which are a focus of regulation. Seabed interactions of wastes are complex, depending on current velocity, seabed substrate and waste material characteristics. The accuracy achieved in modelling intensity and spatial extent of impacts is contingent upon the representation of this interaction and its implications for resuspension. We used benthic flumes to study resuspension processes at 11 salmon aquaculture sites, covering a range of sediment types. Erosion rates and critical entrainment stress were computed at the cage edge and between 100 and 500 m away, characterising seabed erodibility in highly impacted and less impacted sediments. Heavily impacted cage-edge sediments had an erosion threshold (mean 0.02 N m-2) that was an order of magnitude lower, and markedly less heterogeneous, than that of nearby less impacted sediments (mean across sites 0.19 N m-2). This likely reflects a seabed which was smothered by waste material close to the depositional centre. Further out, the covering of waste material is less continuous, thinner, and more admixed with underlying sediments. Bed erosion rates were found to be a linear function of excess stress. The results provide important information on how benthic flumes can be deployed to collect spatial and temporal data for parameterisation of erosion and entrainment processes in numerical waste transport simulation models such as DEPOMOD, and the comparatively large field-based dataset should contribute to the goal of allowing a more realistic representation of particulate waste in these models.

show abstract

“…It should also be noted that, in addition to their use in deriving new insight into physical processes, zero-mean-shear flows also serve as realistic idealisations of some engineered flows. For example, flows that exhibit large turbulent fluctuations, with only small mean-flow velocities, interacting with porous media can be found in cleaning and decontamination processes (Connolly, Armstrong & Miksad 1983;Valsaraj et al 1997;Orlins & Gulliver 2003;Masaló et al 2008).…”

Section: Introductionmentioning

confidence: 99%