dewatering lagoons

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Dewatering lagoons are used in low rainfall countries where they do not want to inject chemical reagents for dewatering.

These (shallow: approximately 1.8 m deep) lagoons work exclusively on evaporation (therefore, a sealed floor is required to avoid soil pollution). A succession of shallow layers of sludge is dried and several lagoons are required for treatment rotation. When approximately 1 m of dewatered sludge (30 to 40 % of dry solids content) is produced inside the lagoon, it is removed by backhoe loader to a post-drying area.

This process is dimensioned according to the site’s evaporation capability (seasonal variations allowed for). It can only be applied to perfectly stabilised sludge in order to avoid nuisances.