The present invention is directed to the use of a combination of a
polymeric chelant and coagulant to treat metal containing wastewater.
More particularly, the invention is directed at removing copper from CMP
wastewater. The composition includes a combination of (a) a polymeric
chelant derived from a polyamine selected from the group consisting of
diethylenetriamine (DETA), triethylenetetraamine (TETA),
tertraethylenepentaamine (TEPA), poly[vinylamine], and branched or linear
poly[ethylenimine] (PEI); and (b) a water soluble or dispersible
copolymer of a tannin and a cationic monomer selected from the group
consisting of methyl chloride or dimethyl sulfate quaternary salt of
dimethyl aminoethyl acrylate, diethylaminoethyl acrylate,
dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate,
dimethylaminopropyl methacrylamide, dimethylaminopropyl acrylamide, and
diallyl dimethyl ammonium chloride.