Dewatering tubes
Fly ash or pulverized fuel ash (PFA) from the combustion process in power stations needs to be contained and treated onsite to avoid air pollution and to minimise environmental issues it may pose around the plant. Proper treatment enables it to be reused as a lightweight fill material or partial concrete replacement.
Traditionally, treatment consisted of filtering the vented fumes from the furnace and then flushing the fly ash into settling ponds where it would gradually be deposited on the pond bottom before eventually being removed for processing or disposal. The space needed for these settlement ponds and the risk of contamination from them is not the most sustainable solution, especially since the PFA removed from the settlement ponds would ultimately need dewatering anyway.
The dewatering of the ash to enable it to be reused as a bone dry construction material can alternatively be achieved by using geosynthetic tubes. These tubes can be used to remove water from any sludge in a variety of applications; from removing potential contaminants from sludge dredged from lakes or riverbeds to treating mine tailings or the fuel ash from either coal or biofuel fired power stations. Dewatering tubes provide a more efficient, cost-effective and sustainable technology.
Volume reductions up to 85% are achieved from the pumped sludge to deliver the bone-dry end material. The sludge pumped towards the Enka-D-Tube is maintained in solution through the addition of either a bentonite or polymer flocculant. Inside the tubes, a natural filter (cake) is created against the special woven fabric the tube is fabricated from; this fabric ensures water permeability and filtration in the initial stage.
Thereafter, the cake helps to filter the sludge. Clean water will run out of the tube and is gathered in cut-off drains to guide it back to the plant or mine for reuse. In order to facilitate an optimal run-off from the full circumference of the tube, Enkadrain can be rolled out under the tube.
Dewatered slurry can be easily excavated from the Enka-D-Tubes. Tubes can be positioned in bays to facilitate ease of use typically with one tube being filled, one standing whilst dewatering and dry tubes being excavated and removed before a new tube is installed for filling.
Enka-D-Tubes are pumped to 70-80% capacity enabling rapid dewatering of the slurry aided by the use of Enkadrain beneath the tube to enable dewatering through the full circumference.
Functions:
- Filtration
- Containment
- Drainage
Relevant products:
