WasteWater Sludge Drying Process

Sludge Drying involves the process of reducing water content in the sludge generated by using the principle of vaporization of water. In conventional sludge drying beds in effluent wastewater plant, vapor pressure differences is the main driving force for evaporation to take place to the atmosphere. In industrial wastewater treatment plant drying apparatus, auxiliary heat is applied in order to increase the vapor-holding capacity of the surrounding air and this contributes towards the latent heat necessary for the sludge water evaporation. The purpose of heat drying is to remove the moisture as much as possible so that it can be burned and disposed efficiently or maybe can be processed further and turned into fertilizer.

The temperature between the sludge and air interface can be taken as equivalent to the wet-bulk sludge temperature of the overall volume of drying air. All these can only be true only if the temperature of the air and surrounding surface of the container is more or less the same. Drying is important in fertilizer manufacturing to allow the grinding and mixture of the sludge, to compact its weight, and to stop it from continued biological action that will degrade it further. The moisture content of the dried sludge is best controlled and removed until it is below 10 percent. For further review on this theory and its application applied in specific types of drying equipment, refer to Sludge Dryers.

Drying can be accelerated and the results achieved faster by exposing more areas to the drying air stream supply. In fact, maximum contact between dry air and wet sludge should be made possible so that you have maximum humidity differences between both interfaces. All these will help towards smooth operation and efficient use of energy and the factors mentioned earlier should be taken into account towards selection of industrial sludge dryers, which helps towards the disposal.

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