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22. What type of waste water treatment will be used? <br />X _ municipal individual (on -site) other <br />The facility will dispose of approximately 80,000 gallons <br />of wastewater per day (assuming a 28-shop case) into the <br />municipal/metropolitan sewage treatment system. Wastewater <br />will be pretreated at the facility to ensure compliance <br />with applicable industrial wastewater effluent require- <br />ments, including the federal categorical standards and <br />local pretreatment limitations for the metropolitan <br />disposal system for metals, and cyanide concentrations, <br />wastewater pH, and any applicable federal regulations for. <br />wastewater discharges. <br />Environmental Protection Agency (EPA) categorical <br />wastewater pretreatment regulations 40 CRF Part 413, for <br />electroplating facilities and 40 CFR Part 433, for metal <br />finishing facilities apply to the proposed facility. <br />Local pretreatment limitations for the metropolitan <br />disposal system (MDS) as set by the Metropolitan Waste <br />Control Commission (MWCC) also apply to the facility (refer <br />to Attachment 7 which presents the MDS limitations on <br />discharges (6 MCAR § 6.014) which are the MWCC's <br />pretreatment standards for the project). <br />Metals which will be limited by concentration in the <br />wastewater discharge include cadmium, total chromium, <br />co -timer, lead, nickel, and zinc. There is also a limitation <br />for meresrv, but it is expected that mercury concentrations <br />will be below minimal detectable limits in the wastewater <br />discharge from the project to the sanitary sewer. The <br />total cyanide concentration and pH will also be limited. <br />In addition, the facility must pay for discharging total <br />suspended solids concentrations or chemical oxygen 'demand <br />levels over set base levels. Plastic polymers used for <br />metal precipitation will contribute to the total suspended <br />solids component. <br />Processes to be used at the facility to remove metals from <br />the incoming waste stream will include ion exchange, <br />activated carbon absorption, chromium reduction, <br />electrochemical recovery, metal precipitation, filter <br />press, and sludge thickening processes. Cyanide removal <br />will be accomplished with a cyanide oxidation process. <br />After metals removal, wastewater from these processes will <br />be treated further by clarification and neutralization, and <br />multimedia or sand filtration. <br />Refer to Attachment 8, a letter from Edward J. Conway of <br />Pope -Reid Associates, Incorporated, which discusses methods <br />to be used to comply with the MDS limitations on - - <br />discharges. <br />Ep <br />