Challenge

Surface Technology, Inc. of Elkridge, Maryland knew they needed a larger filter press.  What they didn’t know was how the new press was going to improve their whole system.

Surface Technology, Inc. cuts granite and Corian to make custom countertops.  They cut the material on saws and CNC machines using water to cool the blade and remove the waste material.  They then wet-sand semi-finished countertops using water-cooled hand sanders.  In the process, they use tremendous amounts of water.  They use a filter press to recover the water for reuse and dewater the solids for landfill.  There is currently no commercial value for the waste solids.

They had a small, 3 cubic foot filter press and needed a larger one as well as presses for sister plants in Colorado and Florida.  In March 2004, they contacted Siemens Water Technologies, who sent their manufacturer’s rep, Steve Levin of Process Solutions, to visit their headquarters at the Maryland facility. 

He found that their current filter press system was causing them problems. 

• It was too small.
• It was unable to make good cakes.
• They were running three cycles per eight-hour shift.
• The cloths had to be pressure washed after each cycle, causing them to swap-out a spare set of plates and cloths after every cycle. 
• They were unable to keep up with the plant water usage, so they were adding city water to the recycle loop.
• The existing “system” required adding precoat to every batch. 
• They had a dedicated operator assigned to the press, who was either running the press or cleaning the cloths.

Solution

Levin told them there was a better solution.  With the correct cloth selection and sizing, Surface Technology, Inc. could run a filter press unmanned, without precoat, and they wouldn’t have to wash the cloths after every cycle.  Phil Wittkamp, Title Special Operations Manager at Surface Technology, Inc., was skeptical.  Due to his experience with the original filter press, he had extremely low expectations with regard to the operation. 

But he went ahead and sent samples to the Siemens Water Technologies lab in Holland, Michigan.  Siemens Water Technologies performed a dewatering analysis on their sludge and selected the best filter plate cloth and filter press size for their application.

Results

In April 2004, Surface Technology, Inc. purchased the recommended filter press, which was a recessed chamber, 30 cubic foot expandable to 50 cubic foot, gasketed plate J-Press® with a semi-automatic plate shifter from Siemens Water Technologies.  The results exceeded their expectations. 

• The Maryland operation is now running for six days before they have to empty the press. 
• They are producing all the water they need. 
• The filter cakes are higher solids than before, they do not need to add polymer, and they do not need to wash cloths. 
• By using the J-Press® filter press that was the best fit for their system, Surface Technology, Inc. lowered their operating expenses. 
• They accomplished this by eliminating the cost of polymer and city water, reducing labor cost and lowering hauling cost—a result of dryer cakes.

Due to increased production and plant expansion, the filter press will soon be expanded to 50 cubic foot.