Restoring filter efficiency

Over time, a significant amount of sediment accumulated at the immediate inlet to the filter, despite upstream pre-treatment. 

After trying to do this using hand tools, we quickly realised that the extent of the accumulation was far too great.  So we had to call in a specialist company. The cleaning was carried out in two stages: 

• Step 1 : the workers moistened the sediment with water from the hydrocureuse to make it wetter.
• Step 2 : the sediment was sucked up by the hydro-scraper.

This cleaning operation was carried out on the first few metres of the filter.The collected sludge was evacuated to a dedicated site. 

This was the first operation of this type since the filter was created.

This operation highlighted the fact that the pontoon at the entrance to the filter had not been designed for such an operation. Accessibility will therefore be improved to facilitate future operations. 

The work took place over two mornings on 7 and 9 August 2024.