BALEEN: THICKENING SILT WITH A GEOTEXTILE FILTER
Thickening – i.e. dewatering – silt has considerable benefits. Smals uses a technique that is as ingenious as it is effective: the Baleen Rapid Dewatering System (RDS). By adding a flocculant and using water-permeable bags, we can significantly reduce the volume, often by as much as half. In many cases the resulting thick, dry mass can also be reused as a building material, e.g. for dams and dykes.
Smart dredging
The process starts with a GPS-controlled cutter-suction dredger, which easily sucks up the layer of mud, silt and slurry from the bed – with centimetre precision in terms of depth and location. This generates hardly any turbidity in the water. The dredged mass is then transported via a pipeline to an area with large, woven bags: geotextile containers. Smals adds polymers at the last moment.
Polymer injection
Thanks to our experience and use of the latest technology, we are able to add the polymers at just the right moment and in just the right quantity. Nothing is lost. The injection station is compact, mobile and computer-controlled. It can be installed anywhere, even in locations with no electricity or fresh water. These polymers do not form a chemical bond, but trigger a process that causes the dredged particles to clump together. The polymers and the particles of silt become electrostatically attracted. Large flakes of solid constituents are left behind in the bag, while clean water flows away through the pores, back to its place of origin
Preparation
A basin created using an excavator or with the help of artificial dykes works perfectly well as a dewatering site. Film or another protective layer ensures the water collects in the basin and can then flow away or be pumped back to its original location.
Thickening silt using geotextiles saves time and storage space, as well as reducing transport and disposal costs. It compares favourably with the traditional evaporation method or mechanical dewatering. The dewatered silt can be used in construction, making the process even more attractive.
In Northeast Groningen Smals has reinforced dykes using thickened silt removed from the river. As a result, the river is able to flow faster and transport more water. This project involved dredging 120,000 cubic metres of silt and calculations have revealed that the risk of flooding has been eliminated for the next thirty years. The river banks are also now environmentally friendly as a result.
We maintain a constant focus on the environment – whether we are removing silt and transforming a problem into a useful raw material, or extracting construction sand over a number of years and developing a valuable nature and recreation area in the process.
We maintain a constant focus on the environment – whether we are removing silt and transforming a problem into a useful raw material, or extracting construction sand over a number of years and developing a valuable nature and recreation area in the process.