Belt filter is the use of two highly permeable filter cloth in a group of pressurized pumping rolling, so that the sludge into the device will be in the middle of filter cloth filter press dry. Belt filter is the most important function of dehydration, dehydration process different devices, but the principles are similar.

Before dehydration, pre-dehydration process is very important, can increase the solid concentration of sludge, improve dehydration efficiency. In general, two drum type pre-dewatering machines are used for pre-dewatering. Sludge particles mixed with the flocculant in the pre-dewatering machine are left in the machine. Water flows out of the machine through the filter cloth. After sludge accumulates to a certain amount, From the exit of the pre-dehydrator to the belt filter.

The pre-dehydrated sludge inlet belt filter, the first procedure is gravity drainage, this procedure is to once again raise the sludge solid content, ready for the next working procedure. After gravity drainage, the sludge was again drained, and evenly distributed on the filter cloth, and gradually began to pressure. The thickness of the sludge on the cloth will depend on the nature of the sludge and the speed of the filter cloth.