Ask the Expert Question-and-Answer Archive (Wastewater Treatment)
by Mike McGinness, EcoShield Environmental Systems, Inc.
October, 2002Magnesium Rather Than Sodium Hydroxide for Metals Precipitation
Q. Is it practical to use magnesium hydroxide rather than sodium hydroxide to precipitate metals, with reduced sludge volume, in metal finishing wastewater.
A. Yes it is, but keep in mind that the magnesium hydroxide must be stirred and fed as a slurry so it is a little more complicated to dispense. It comes as a powder and has a limited solubility. One nice advantage is the upper limit on pH if you overtreat is about 10 and the safety hazard of caustic is eliminated as well.
