Micro-bubble curtains: new study looks at impact on sediment dispersal

Swansea University researchers are examining the effectiveness of a sediment management system which could help to mitigate the impact of sediment movement in sensitive marine habitats following construction work, including marine renewable energy (MRE) developments or the disposal of dredge spoils.

Bubble tubing

The study is part of the three-year SEACAMS2 project managed through Swansea University and Bangor University and part-funded by the European Regional Development Fund (ERDF) through the Welsh Government.

Researchers at Swansea University have teamed up with the environmental engineering company Frog Environmental Ltd to test the performance and effectiveness of Bubble Tubing©products as a potential sediment management control tool in marine and coastal environments. Bubble Tubing © is a fine bubble linear diffuser system which releases micro-bubbles in water forming bubble curtains.

The study

These curtains have previously been used in freshwater systems for a range of environmental protection applications, and now the SEACAMS2 research team studied their effectiveness on sediment movement in seawater.

Frog Environmental director Leela O’Dea said: “The mobilisation of sediment causes considerable problems for construction projects affecting aquatic systems. Natural Resources Wales (NRW) and construction companies are looking for solutions to limit the run-off and dispersal of sediments. For us as ecological engineers this provides growing commercial opportunities.”

The impact of MRE

Increases in MRE developments throughout the UK and overseas are likely to cause sediment dispersion during its construction, maintenance and de-commissioning. Smothering, erosion and sediment dispersal kills or displaces animals living in and on the seafloor and can impoverish the natural fauna. Controlling sediment via Bubble curtains could offer a potential mitigation solution.

Researchers at Swansea University’s SEACAMS 2 project in the College of Science have conducted controlled laboratory trials focussing on how parallel layers of Bubble Tubing© affect sediment dispersal in seawater conditions.

Trials of the bubble curtains made of Bubble Tubing© found:

  • It is an effective product at limiting sediment dispersal in seawater.
  • Multiple layers of Bubble Tubing© were found to be more effective at retaining a large quantity of sediment including finer-grained sediment (63-125 µm).
  • Over 50% of the sediment was prevented from passing through a single Bubble Tubing©, but up to three parallel layers of Bubble Tubing© prevented as much as 90% of the sediment passing through, even of fine-grained sediment.
  • Multiple layers of Bubble Tubing© may enhance its performance as a sediment control product.

SEACAMSERDF logo for RISE press release

 

 

 

 

 

 

Anouska Mendzil, research assistant at SEACAMS2 project, Swansea University said: “We have undertaken a series of laboratory trials testing the Bubble Tubing© product with different sediment grain-sizes under different scenarios in collaboration with Frog Environmental. The results of the trial are encouraging and indicate that there is potential for the product to be used as a sediment management tool in marine and coastal areas, which may be particularly important in areas with sensitive habitats.”

Ms O’Dea said: “The results correspond with our observations at construction sites, but so far we were unable to quantify the effectiveness of Bubble Tubing©. We would love to upscale the research with SEACAMS2 and take the trials out into the field.”

Ms Mendzil said: “The project aims to develop opportunities for Welsh businesses in the low carbon energy and environment sector, and is an investment in the potential offered by the marine economy and marine renewable energy sector.Posted by Public Relations Office <>