LEWA pumps offer the following advantages for metering of media for phosphate precipitation in water treatment:
What happens during a phosphate precipitation?
A phosphate precipitation is a physico-chemical reaction in which salts of trivalent metals are used to precipitate phosphates. Non-hazardous iron (III) and aluminium salts are applied for this purpose. Injecting metal salts creates positively charged metal ions which react with negatively charged phosphate ions. The resulting difficultly soluble metal phosphate is precipitated in form of fine floc.
The precipitant has to be injected at the right point in order for the ions to react sufficiently. Subsequently, a flocculation phase ensues during which the fine precipitation products aggregate to settleable floc.