Sludge which settles in the secondary clarifier is picked up by the sludge scoop and can flow by gravity to digestion and storage facilities.

Crafts features: high sludge treatment burden, high outlet water standard, and no need of the Secondary sedimentation tank like the traditional crafts.

Simultaneously, the excess activated sludge that drained from the sediment pool returned the hydrolysis- acidification pool could be degraded, so the treatment cost of sludge could be lower.