EPA regulations about the treatment of wastewater; it's a tune that many industries, including tool & die are quite familiar with.
One of the major sets of regulations in place for the treatment of tool & die wastewater are the Metal Molding and Casting (MMC) Effluent Guidelines and Standards, which cover 28 process segments (like casting quenching and mold cooling). All of those processes use quite a bit of water, which has to be heavily treated because of the heavy metals, oil and grease it contains. Let's take a brief look at the steps that go into treating tool & die wastewater.
About the Process...
As the illustration above shows, the treatment of wastewater produced by tool & die facilities involves multiple stages:
Waste streams are collected in an equalization collection tank
Wastewater is transferred to a treatment tank where a polymer is added to promote settling
Settled sludge is moved to a thickening tank for chemical conditioning
Slurry is pumped through a filter press for dewatering
Solids are disposed of and treated water is released into the sewer or reused in the facility
About the Presses...
When it comes to filter press placement with your facility, we recommend putting it in a centralized location where it can easily be linked to the equalization, precoat and sludge holding tanks (as shown in the illustration above).
We also recommend using filter plates that are made of polypropylene, which will hold up best against the corrosive slurry. Membrane (diaphragm) or recessed chamber filter plates would also work well.
And when it comes to filter cloths, gasketed cloths are the best type to use in this process. Gasketed filter cloths are less likely to leak the potentially hazardous slurry. It is best to precoat the filter cloths to reduce cloth binding and cleaning problems. If filter cloths are properly maintained they will produce filter cakes that are 30-50% total solids by weight.
Do you have questions about filter presses? Contact one of our product experts or download our guide, 9 Reasons to Build Your Case for Evoqua's JWI J-Press® Filter Press, to learn more about these extremely versatile pieces of equipment.