Sludge Drying Bed – Wastewater Treatment

Sludge Drying Bed

It is a rectangular pit excavated to the required depth. The beds are filled with gravel and coarse sand as a filter. Open joints underdrain pipes are laid below the gravel layer.

Sludge Drying Bed - Wastewater Treatment

The beds are about 15 m x 30m in plan and are surrounded by brick walls rising about 1 m above the sand surface.

The sewage sludge from the digestion tank is brought and spread over the top of the drying beds to a depth of about 20 to 30 cm. 

A portion of the moisture drains through the bed, while most of it is evaporated to the atmosphere. It usually takes about 2 weeks to 2 months to dry the sludge. After drying, the sludge cakes are removed and used as manure.

Read Also: 

Sludge Digestion Tank

Sludge Volume Index