Iron and Steel Manufacturing. 40 CFR Part 420

Transcription

1 Iron and Steel Manufacturing 40 CFR Part 420

2 Description of the Industry Three basic types for facilities Integrated steel mills Non-integrated steel mills Stand-alone facilities

3 Iron and Steelmaking Operations

4 Forming & Finishing Operations

5 Manufacturing Operations Cokemaking (Subpart A) Two types of cokemaking facilities By-product recovery coke plants Waste ammonia liquor (ammonia, cyanide, sulfide, benzene, and phenols) Non-recovery coke plants

6 By-Product Recovery Cokemaking

7 Manufacturing Operations Sintering (Subpart B) Recovered of iron-bearing materials are mixed with iron ore, limestone, and finely divided fuel.

8 Manufacturing Operations Ironmaking (Subpart C) Iron ore is reduced to molten iron in a blast furnace.

9 Manufacturing Operations Steelmaking (Subpart D) Basic Oxygen Furnace High-tonnage carbon steels Electric Arc Furnace Low-tonnage carbon, alloy, and stainless steels BOP Q-BOP

10 Manufacturing Operations Vacuum Degassing (Subpart E) Refining process in which gases are removed from molten steel prior to casting.

11 Manufacturing Operations Continuous Casting (Subpart F) Converts molten steel into a semifinished product or shape through water cooled molds.

12 Manufacturing Operations Hot Forming (Subpart G) Preheated solidified steel is reshaped through a series of forming steps using mechanical pressure applied to work rolls.

13 Manufacturing Operations Salt Bath Descaling (Subpart H) Surface treatment operation. Two step operation Molten salt baths Water quenching Can be a batch or continuous process

14 Salt Bath Descaling Batch Process

15 Salt Bath Descaling Continuous Process

16 Manufacturing Operations Acid Pickling Chemically removes oxides and scale Carbon steel hydrochloric acid Stainless steel sulfuric, hydrochloric, and/or hydrofluoric acids

17 Manufacturing Operations Cold Forming (Subpart J) Process in which unheated steel is passed through rolls Reduces thickness Produces a smooth surface Develops controlled mechanical properties in the steel

18 Manufacturing Operations Alkaline Cleaning Steel and steel products are immersed in alkaline cleaning baths and its rinsing operations There are no promulgated categorical standards for this subpart Facilities subject to this subpart must comply with the general pretreatment regulations at 40 CFR Part 403

19 Manufacturing Operations Hot Coating (Subpart L) Involves immersing precleaned steel into molten metal baths of Tin, Zinc (hot galvanizing), Combinations of lead and tin (terne coating), or Combinations of aluminum and zinc (galvalume coating)

20 Manufacturing Operations Other (Subpart M) Briquetting Recycles and reuses fine materials Requires no discharge of process wastewaters to the POTW Direct-Reduced Iron (DRI) Similar iron making reaction as blast furnace ironmaking No pretreatment standards for this operation Forging Type of steel forming No pretreatment standards for this operation

21 Implementation of Regulations Pretreatment standards are mass limits (production-based) ph limits of 6.0 to 9.0 [40 CFR ] Part 420 regulates discharges of process wastewater generated in all production operations Co-treating non-process wastewater is allowed in some circumstances [40 CFR (r)] Additional pollutant allowances for non-process wastewater [40 CFR ]

22 40 CFR Part 420 Process and Non-Process Wastewaters

23 Process and Non-Process Wastewaters (continued)

24 Other Special Conditions Subpart A: Cokemaking Subpart B: Sintering Additional loading allowance for wastewaters from specific processes (see and ). No discharge of process wastewater pollutant to POTWS from non-recovery cokemaking processes. No discharge of process wastewater pollutants to the POTWs from dry air pollution control systems. The pretreatment standards for cyanide and phenols apply only when sintering wastewater is cotreated with ironmaking wastewater. Special compliance monitoring point for 2,3,7,8- TCDF. Ammonia limit is not applicable if POTW has nitrification capabilities.

25 Other Special Conditions Subpart C: Ironmaking Subpart D: Steelmaking Subpart J: Cold Forming Subpart L: Hot Coating) Subpart M: Other Operations The iron blast furnace ammonia limit is not applicable if POTW has nitrification capabilities. No discharge of process wastewater pollutants from the electric arc furnace steelmaking-semi-wet process and the basic oxygen furnace steelmakingsemi-wet process. Limitations for chromium and nickel are applicable only if cold forming wastewaters are treated with descaling or combination acid pickling wastewaters. Limitations for hexavalent chromium is applicable only to galvanizing operations which discharge wastewaters from the chromate rinse step. No discharge of process wastewater pollutants to POTWs from the briquetting operation.

26 Calculating Limits - Example Combination acid pickling spend acid, rinse waters, and fume scrubber to treatment Spent rolling emulsions and solutions to treatment 2 tons of steel plate products Combination Acid Pickling Cold Forming Annealing Alkaline Cleaning Metal Finishing Finished Product Alkaline rinse wastewater to treatment Plating rinse wastewater to treatment

27 Calculating Limits (continued) Wastewater flows: Alkaline cleaning prior to metal finishing: 50,000 gpd Metal finishing rinse wastewater: 35,000 gpd Total Wastewater Flow per day: 200,000 gpd The alkaline cleaning prior to the metal finishing and the metal plating rinse wastewaters are subject to 40 CFR Part 433 (PSNS) The reminder of the wastewaters are subject to 40 CFR Part 420 (PSNS)

28 Calculating Limits (continued) Operation Production Pollutant Chromium Units Daily Max 30 day average Combo Acid Pickling [420.96(c)(3)] Combo Acid Pickling (fume scrubber) [420.96)(c)(6) Cold-Forming [ (a)(2)] Metal Finishing [433.17] 2 tons per day lbs/1,000 lbs Facility does have one fume scrubber over the pickling bath lbs/day kg/day lbs/day 2 tons per day lbs/1,000 lbs lbs/day Not applicable mg/l lbs/day Total Allowable Mass (Chromium) lbs/day Adjust concentration limits mg/l

29 Treatment Options Physical / Chemical Treatment Equalization Tar Removal Ammonia Stripping Cyanide and Metals Removal Oily Waste Treatment Solids Separation Carbon Dioxide Injection Polishing Ammonia Stripping

30 Treatment Options Biological Treatment Conventional Activated Sludge Sequencing Batch Reactor Attached Growth/Fixed Film Biological Denitrification Sludge Handling Gravity Thickening Rotary Vacuum Filtration Pressure Filtration Belt Filtration Centrifugation Sludge drying

31 Best Management Practices Routine Monitoring Flow Management Training and Supervision Production Planning and Sequencing Process or Equipment Modification Raw Material and Product Substitution or Elimination Oil Management and Preventive Maintenance Loss Prevention and Housekeeping Waste Segregation and Separation