Organic and inorganic slurries dewatered and dried in one operation

A DryVac dewatering and drying filter press system can remove up to 99.9 percent of liquid material from virtually any waste stream.

DryVac - How it Works

The DryVac technology provides a cost effective integrated process for dewatering and drying, handling organic and inorganic waste streams equally well. In a single operation involving two stages, the liquid waste is first dewatered and then dried. While the DryVac unit appears physically similar to standard plate filter presses, the actual plates are replaced by DryVac Elastic Envelope Modules (DEEMs){patent pending}. These modules expand and contract according to pressure being applied either externally or internally.

Stage One: the dewatering takes place in a very similar way as with conventional plate presses. That is, conditioned sludge is pumped into the sludge chambers, which are lined with filter cloths; solids are retained in the press while liquids are forced out.

Stage Two: is where the DryVac process differs from standard plate filtration presses. In the drying stage, low-pressure steam is used to inflate the DEEMs and, at the same time, a vacuum is applied to the filtrate ports. During this process the cake is squeezed as the DEEMs inflate. The application of heat to the filter cake and the pulling of a vacuum on the filter chamber result in the remaining water being vaporized at low temperature. The walls of the expanding DEEMs remain in contact with the sludge ensuring effective heat transfer. By regulating the duration of the drying stage, the dry solids of the end product can be accurately controlled. Because the cake is much drier than with a conventional press, at the end of the drying cycle the solids drop out easier, leaving the DEEMs relatively clean.

The process is energy efficient and it allows wide flexibility of design when retrofitting existing presses. The DryVac systems are available in capacities ranging from 0.06m3 to 20m3 or more. The system is supplied in modular formats for ease of installation allowing maximum flexibility; fully mobile units are also available.

Feed Cycle

Conditioned sludge is fed into the chambers with the feed pump

Pressure and Air Blow Cycle

Pressurized air is introduced into the chamber to squeeze the cake.

Pressurized air is blown through the cake to remove water.

 Drying Cycle

Steam is applied to the steam chamber.

Vacuum is drawn on the ‘cake’ via the filtrate ports.

17 Cubic Meter Unit, 1 of 4 Units 

Coventry, United Kingdom 

Automated units are available
Negligible odor emissions
No explosive dust environment
1 BAR steam (15 PSI)

Materials can be tested
at our main facility or
by our mobile DryVac units;

Surplus activated, primary or diegested materials
Varible feedstocks
Dewaters to 20-40%
Dry materials to 99%
Low Maintenance
Automated Operation
Skid mounted if desired
Modular Construction
Retrofits to Exsisitng presses

Dewatering and thermal vacuum dehydration
Combined effect of pressure, heat and vacuum
Can make use of waste heat
Excellent heat sink for CHP schem


Steam and vacuum are turned off and DEEMs{patent pending} deflate.

Dry product drops out as the press is opened.