What is the maximum sludge depth recommended on gravity drying beds?

The maximum sludge depth recommended on gravity drying beds is 20 to 30 cm (8 to 12 in) because this range allows for optimal moisture removal while ensuring that the sludge can adequately dewater without causing issues such as excessive compaction or anaerobic conditions. If the sludge layer is too deep, it can hinder the drying process by limiting air circulation and reducing the efficiency of evaporation. Additionally, a shallower depth promotes uniform drying across the drying bed's surface, which is essential for effective treatment and management of the sludge. Maintaining the sludge within this recommended depth balances the need for efficient water removal and the management of the physical properties of the sludge for further processing or disposal.