Sludge drying technology originated earlier. At the beginning of the 19th century, the Germans invented the world's first plate and frame filter press. Now, after two hundred years of development, various types of filter presses have been born, which are used in different scenes. 

    The domestic sludge drying industry started relatively late and sprouted in the period of reform and opening up at the end of 1970s. Due to the restriction of the inherent policy of heavy water and light mud, it can be seen that the domestic large-scale sludge filter press manufacturers have been set up gradually since 1990. Sludge drying has never been developed.

　　In fact, the policy of heavy water and light mud has been gradually changed in China since 2010. there are a large number of water treatment environmental protection exhibitions covering sludge drying in China every year, and we can see the momentum of vigorous development of various environmental protection enterprises.

　　Sludge drying, also known as sludge dewatering, refers to the process of removing most of the water content from the sludge through percolation or evaporation, generally refers to the use of sludge drying field (bed) and other self-evaporation facilities.

　　After the sludge is concentrated, the water content of the sludge is further reduced by physical methods, which is convenient for the transportation, accumulation, utilization or further treatment of the sludge.

　　There are two kinds of dehydration (drying): natural evaporation and mechanical dehydration.

　　Traditionally, the mechanical dewatering method is called sludge dewatering, and the natural evaporation method is called sludge drying.

　　Although the methods are different, they are all measures to further reduce the moisture content of sludge.