In this application filter presses are used mainly for the filtration of slurries proceeding from wastewater treatment plants. Slurry is made up of the hydroxides of precipitate metals in waste water treatment process of galvanic, anodization or surface cleaning treatment of stainless steel rolled sections(pickling, phosphatising).
Sometimes filter presses are also used for the continuous purification of phosphatizing baths with the aim of keeping the acid clean enough and assuring the removal of suspended solids in the tanks where it is contained.
The characteristics of filter materials should protect from the corrosivity due to the highly acid bath and assure a very good filtrate quality in order to have its recirculation in the same bath.
Main Application of WWTP in galvanic industry:
- Filtration of chromium hydroxide
- Filtration of nickel hydroxide
- Filtration of zinc hydroxide
- Filtration of cadmium hydroxide
- Filtration of aluminium hydroxide
WWTP in pickling industry:
- Filtration of iron hydroxide
- Filtration of calcium sulphate