Technical Bulletin No. 0807: Bench-scale Testing of Processes to Reduce Metals Concentrations in Pulp and Paper Mill Wastewaters

Several chemical processes were examined at bench scale to evaluate their potential to remove metals from selected pulp and paper mill wastewaters to discharge limits based on GLI water quality criteria. The processes included (a) an electrochemical process (Andco), (b) a sulfide-based precipitation process (Sulfex), and (c) the FeCl2/Biox process, which incorporates adsorption of metals on iron hydroxide introduced into existing pulp and paper mill activated sludge processes. Mercury poses a particularly severe compliance problem because (unlike other metals) dilution in the mixing zone cannot be considered in calculation of its discharge limit.