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<br />3 <br />PERMIT BRIEFING MEMO <br /> <br />1. Facility Description <br /> <br />TK Finishing is a job shop that engages in black oxide treatment and corrosion prevention of customer <br />supplied steel metal parts. Wastewater discharged from TK Finishing’s process is subject to the Metal <br />Finshing Categorical Standards found at 40 CFR 433.17. TK Finishing is generally open for business 4 <br />days per week 7 am to 4. Process operations are conducted as jobs become available. <br /> <br />2. Discharge description: <br /> <br />Discharge is rinse water only. TK Finishing uses a series of 5 tanks for the treatment process of the metal <br />parts. Tank 1 contains Electro 100 which is a cleaner and tank 3 contains Black Oxide 110 which is the <br />Black Oxide treatment. Tanks 2 and 4 are rinse waters which discharge to the sewer system. Tank 5 <br />contains oil which is applied to the metal parts to protect the finishing. Tanks 1, 3, and 5 are not <br />discharged to the sewer system. <br /> <br /> From July 2021 <br />through <br />July 2022 <br />From November 2017 <br />through <br />July 2022 <br />Average Process Flow 34 gpd 42 gpd <br />Maximum Process Flow 92 gpd 2,169 gpd <br /> <br /> <br />3. Sample Site Description <br /> <br />Sample Site Outfall # 4045 is located at the northwest corner of the suite where the rinse tanks (2nd and 4th <br />tanks) discharge rinse water from the black oxide line into a 55-gallon drum, where pH is adjusted. A <br />sump pump pumps the wastewater to the City of South Bend Sewer System. Compliance samples are <br />collected from the discharge stream that flows from the pH adjustment 55-gallon drum to the final <br />discharge 55-gallon drum. This sampling location is deemed by the Industrial Pretreatment Group to be <br />end of pipe and end of process; sanitary waste excluded. <br /> <br />4. Wastewater Treatment <br /> <br />Wastewater treatment consists of pH neutralization using Hydrochloric Acid (Muriatic Acid) and Sodium <br />Hydroxide. <br /> <br />5. Classification <br /> <br />TK Finishing is classified as a Categorical Industrial User (CIU). Specifically, TK Finishing is classified <br />as a metal finisher covered by 40 CFR 433.17 (PSNS) due to the black oxide process of metal parts. TK <br />Finishing is categorized as a B industry in accordance with the City’s EPA approved Industrial <br />Pretreatment Program in which all Categorical Industries are classified as a Class B at minimum. <br />However, due to low daily discharge volumes, TK Finishing’s monitoring schedule is the same as a D <br />industry. <br /> <br />6. Calculation of Limits <br /> <br />Limits are applied from 40 CFR 433.17 (PSNS) without modification to the categorical process <br />wastewater flow unless local limitations are more stringent.