A method of removing one or more heavy metals from industrial wastewater by use of a membrane separation process is disclosed. Specifically, the following steps are taken to remove heavy metals from industrial wastewater: (a) collecting an industrial wastewater containing heavy metals in a receptacle suitable to hold said industrial wastewater; (b) adjusting the pH of said system to achieve hydroxide precipitation of said heavy metal in said industrial wastewater; (c) adding an effective amount of a water soluble ethylene dichloride- ammonia polymer having a molecular weight of from about 500 to about 10,000 daltons that contain from about 5 to about 50 mole percent of dithiocarbamate salt groups to react with said heavy metals in said industrial wastewater system; (d) passing said treated industrial wastewater through a submerged membrane, wherein said submerged membrane is an ultrafiltration membrane or a microfiltration membrane; and (e) optionally back-flushing said membrane to remove solids from the membrane surface.