2018 Outstanding Achievement Award in Mines/Landfill/Waste-Water Category
2018 Outstanding Achievement Award
Mogan Lake Turkey
Project Details
Fabric: Mirafi®
Producer: TenCate Geosynthetics
Installation Company: Atlas Maden
Please describe the project specifications
When 2.700.000m³ of sludge needed to be extracted from a 4Km² eutrophic lake in an urban area by means of a dredge with an hourly minimum capacity of 2.000m³ the only appropriate method to reduce the volume by half, was by using TenCate Geotube® dewatering technology. For its reliable track record of successful large scale tube dewatering projects, we were selected as system supplier and involved in the choice of the polyelectrolytes, dosing equipment, hydraulic layout, the design of the dewatering cell and training of onsite personnel.
What was the purpose of this project? What did the client request?
The project aims to put an end to the eutrophic state of the lake that was overgrown with water plants, suffered from cyanobacterial blooms, chlorophyll and nutrients, causing a bad smell. Due to these poor conditions it could hardly be used by the population for recreational purposes.
To extract the sediments without causing more smell and without disrupting the nature reserve, the authorities opted for hydraulic dredging. Using this environmentally friendly method, meant that the sludge was dissolved in more water, increasing the volume to be dredged to over 6.000.000m³.
What is unique or complex about the project?
The uniqueness of this project resides in the way that volume was handled using geosynthetics. Indeed, to treat this kind of volume effectively in a relatively short time only geotextile tube dewatering is an option. To receive over 2.000m³ an hour of dredged material we proposed a design for a dewatering cell on a footprint of no more than 0,1km² on which 4 times 140 tubes rapidly filtered out the solids while the particle free effluent water was guided off site to flow back to the lake.
What were the results of the project?
Using TenCate Geotube® bags saved millions of Euros and tons of CO2 compared to mechanical dewatering. It effectively prevented the development of smell, of erosion and long term occupation of farm land in comparison to decantation basins. The project is in its last stages and already the aquatic life in the lake is visibly improved; clearer water and more fish can be observed. When the last bags will be removed, the temporary occupation of the area is finished and will be restored in its original status.
