The increase in industrialization and population in the recent days the sludge production is also increased which has become difficult to handle it. Sludge used to be incinerated, compost and landfilling before disposal, but as it is not economic and environmentally friendly most of researchers are concentrating on the sludge dewatering process which are sustainable technologies so that sludge can be converted to semi solid which will be easy to handle and transport. Some sludge is used to produce to biogas, organic matter and also source of energy further processing was not done as it contains toxic compounds in it. Hence studies on sludge dewatering can be useful in terms of environmental and economic point of view. The present review work is on study of different properties of sludge, their effect on sludge dewatering, fundamentals of sludge and assessment of sludge dewaterability.

The phosphorus recoveries in municipal wastewater treatment plants (WWTPs) are in much demand as the price of phosphate rock are increased from the last decade. Due to the increase in pollution levels of the sewage sludge, it is difficult to use sewage sludge directly as fertilizers in agricultural fields. The present study aimed to work on the recovery of phosphorus from the deep dewatered liquors in a laboratory, batch test mode. Experiments were conducted to identify the initial characteristics of sludge and for recovery analysis, by varying the phosphorus and Magnesium (Mg:P) molar ratio. Characterization studies were performed by SEM and FTIR for confirmation of struvite formation. Results obtained revealed that recovery is 94% of the incoming phosphorus.

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