Filter press dehydrator / Sludge drying, Recycling drying

There are a lot of kinds of dehydrator for sludge arises from wastewater treatment plants. Among them, filter press dehydrator is a dehydrator which dehydrates sludge by pressing and injecting into limited space called filtering room. Sludge dehydrated by the filter press tends to have lower moisture content compared with other types of dehydrators. Also, because its operation is not continuous but batch, sludges need to be collected with hopper and carried out with conveyers, pumps etc., therefore, it takes times and labor.  This type of dehydrator is also used for sediment sludge.
Slaked lime or other inorganic flocculants are used for flocculants.

There are two types of filter press dehydrator. One of them perform dehydration and filtering by pressing and injecting sludge continuously, and the other one uses diaphragm set in filtering rooms to dehydrate.
For both of them, many filtering rooms are lined up inside the main body and the rooms are separated with filtering cloth. All of these filtering rooms are tightened by oil pressure. 
Sludge containing large amount of water are injected into the filtering rooms. One of these types keeps on injecting more sludge with pumps even all of the filtering room become full. This injection process adds pressure onto sludge and water inside the sludge are filtered and dehydrated. After dehydration is done, oil pressure which was tightening the filtering room are loosen and sludge are dropped off.
The other type performs dehydration and filtering by pumping diaphragm in filtering rooms up with pressed air, water, oils, etc. after the filtering rooms become full, instead of injecting more sludge. Once dehydration is done, filtering rooms are opened by loosening oil pressure and sludge drops off.

The following diagram is about how diaphragm type filter press works.

About types of sludge dewatering / Sludge drying, Recycling drying

About effects of flocculants during drying -1 / Sludge drying, Recycling drying

Comparison of drying between organic sludge and inorganic sludge after dewatering

Comparison between organic sludge and organic matter

Water in the sludge thickened in the sludge thickener tank are removed at dehydration process to a certain degree.
However, moisture content is normally more than 80% and the sludge still has adhesiveness and stickiness. Also, latter processes are not easy because of influence of flocculants. Our drying apparatus of KENKI DRYER with international patented technology can surely dry any sticky, adhesive and viscus sludge, and also materials in liquid state like slurry, without clogging inside of the dryer. Also, because of its simple structure, its price is low and apparatus cost of the dryer can be retrieved by reducing industrial waste disposal cost within 3 years. Dried materials can be recycled as fuel, bacterial fertilizer, soil conditioner, etc. since component of the material is hardly changed because of its low-temperature drying method.
It can be applied to a system with pyrolysis apparatus as well.

Sludge drying

Self-cleaning screw

Methods