Subchapter N—Effluent Guidelines and Standards (Continued)

SUBCHAPTER N—EFFLUENT GUIDELINES AND STANDARDS (CONTINUED)

PART 425—LEATHER TANNING AND 425.23 Effluent limitations representing the degree of effluent reduction attainable FINISHING POINT SOURCE CAT- by the application of the best available EGORY technology economically achievable (BAT). GENERAL PROVISIONS 425.24 New source performance standards (NSPS). Sec. 425.25 Pretreatment standards for existing 425.01 Applicability. sources (PSES). 425.02 General definitions. 425.26 Pretreatment standards for new 425.03 Sulfide analytical methods and appli- sources (PSNS). cability. 425.04 Applicability of sulfide pretreatment Subpart C—Hair Save or Pulp, Non- standards. Chrome Tan, Retan-Wet Finish Sub- 425.05 Compliance dates. category 425.06 Monitoring requirements. 425.30 Applicability; description of the hair Subpart A—Hair Pulp, Chrome Tan, Retan- save or pulp, non-chrome tan, retan-wet Wet Finish Subcategory finish subcategory. 425.31 Effluent limitations representing the 425.10 Applicability; description of the hair degree of effluent reduction attainable pulp, chrome tan, retan-wet finish sub- by the application of the best practicable category. control technology currently available 425.11 Effluent limitations representing the (BPT). degree of effluent reduction attainable 425.32 Effluent limitations representing the by the application of the best practicable degree of effluent reduction attainable control technology currently available by the application of the best conven- (BPT). tional pollutant control technology 425.12 Effluent limitations representing the (BCT). degree of effluent reduction attainable 425.33 Effluent limitations representing the by the application of the best conven- degree of effluent reduction attainable tional pollutant control technology by the application of the best available (BCT). technology economically achievable 425.13 Effluent limitations representing the (BAT). degree of effluent reduction attainable 425.34 New source performance standards by the application of the best available (NSPS). technology economically achievable 425.35 Pretreatment standards for existing (BAT). sources (PSES). 425.14 New source performance standards 425.36 Pretreatment standards for new (NSPS). sources (PSNS). 425.15 Pretreatment standards for existing sources (PSES). Subpart D—Retan-Wet Finish-Sides 425.16 Pretreatment standards for new Subcategory sources (PSNS). 425.40 Applicability; description of the Subpart B—Hair Save, Chrome Tan, Retan- retan-wet finish-sides subcategory. Wet Finish Subcategory 425.41 Effluent limitations representing the degree of effluent reduction attainable 425.20 Applicability; description of the hair by the application of the best practicable save, chrome tan, retan-wet finish sub- control technology currently available category. (BPT). 425.21 Effluent limitations representing the 425.42 Effluent limitations representing the degree of effluent reduction attainable degree of effluent reduction attainable by the application of the best practicable by the application of the best conven- control technology currently available tional pollutant control technology (BPT). (BCT). 425.22 Effluent limitations representing the 425.43 Effluent limitations representing the degree of effluent reduction attainable degree of effluent reduction attainable by the application of the best conven- by the application of the best available tional pollutant control technology technology economically achievable (BCT). (BAT).

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425.44 New source performance standards 425.72 Effluent limitations representing the (NSPS). degree of effluent reduction attainable 425.45 Pretreatment standards for existing by the application of the best conven- sources (PSES). tional pollutant control technology 425.46 Pretreatment standards for new (BCT). sources (PSNS). 425.73 Effluent limitations representing the degree of effluent reduction attainable Subpart E—No Beamhouse Subcategory by the application of the best available technology economically achievable 425.50 Applicability; description of the no (BAT). beamhouse subcategory. 425.74 New source performance standards 425.51 Effluent limitations representing the (NSPS). degree of effluent reduction attainable 425.75 Pretreatment standards for existing by the application of the best practicable sources (PSES). control technology currently available 425.76 Pretreatment standards for new (BPT). sources (PSNS). 425.52 Effluent limitations representing the degree of effluent reduction attainable Subpart H—Pigskin Subcategory by the application of the best conventional pollutant control technology 425.80 Applicability; description of the pig- (BCT). skin subcategory. 425.53 Effluent limitations representing the 425.81 Effluent limitations representing the degree of effluent reduction attainable degree of effluent reduction attainable by the application of the best available by the application of the best practicable technology economically achievable control technology currently available (BAT). (BPT). 425.54 New source performance standards 425.82 Effluent limitations representing the (NSPS). degree of effluent reduction attainable 425.55 Pretreatment standards for existing by the application of the best conven- sources (PSES). tional pollutant control technology 425.56 Pretreatment standards for new (BCT). sources (PSNS). 425.83 Effluent limitations representing the degree of effluent reduction attainable Subpart F—Through-the-Blue Subcategory by the application of the best available 425.60 Applicability; description of the technology economically achievable through-the-blue subcategory. (BAT). 425.61 Effluent limitations representing the 425.84 New source performance standards degree of effluent reduction attainable (NSPS). by the application of the best practicable 425.85 Pretreatment standards for existing control technology currently available sources (PSES). (BPT). 425.86 Pretreatment standards for new 425.62 Effluent limitations representing the sources (PSNS). degree of effluent reduction attainable by the application of the best conven- Subpart I—Retan-Wet Finish-Splits tional pollutant control technology Subcategory (BCT). 425.63 Effluent limitations representing the 425.90 Applicability; description of the degree of effluent reduction attainable retan-wet finish-splits subcategory. by the application of the best available 425.91 Effluent limitations representing the technology economically achievable degree of effluent reduction attainable (BAT). by the application of the best practicable 425.64 New source performance standards control technology currently available (NSPS). (BPT). 425.65 Pretreatment standards for existing 425.92 Effluent limitations representing the sources (PSES). degree of effluent reduction attainable 425.66 Pretreatment standards for new by the application of the best conven- sources (PSNS). tional pollutant control technology (BCT). Subpart G—Shearling Subcategory 425.93 Effluent limitations representing the degree of effluent reduction attainable 425.70 Applicability; description of the by the application of the best available shearling subcategory. technology economically achievable 425.71 Effluent limitations representing the (BAT). degree of effluent reduction attainable 425.94 New source performance standards by the application of the best practicable (NSPS). control technology currently available 425.95 Pretreatment standards for existing (BPT). sources (PSES).

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425.96 Pretreatment standards for new (h) ‘‘Raw material’’ means the hides sources (PSNS). received by the tannery except for fa- APPENDIX A TO PART 425—POTASSIUM FERRI- cilities covered by subpart D and sub- CYANIDE TITRATION METHOD part I where ‘‘raw material’’ means the APPENDIX B TO PART 425—MODIFIED MONIER- hide or split in the condition in which WILLIAMS METHOD APPENDIX C TO PART 425—DEFINITION AND it is first placed into a wet process. PROCEDURE FOR THE DETERMINATION OF (i) ‘‘Monthly average’’ means the THE METHOD DETECTION LIMIT arithmetic average of eight (8) indi- AUTHORITY: 33 U.S.C. 1311, 1314 (b), (c), (e) vidual data points from effluent sam- and (g), 1316 (b) and (c), 1317 (b) and (c), 1318 pling and analysis during any calendar and 1361. month. SOURCE: 47 FR 52870, Nov. 23, 1982, unless (j) ‘‘Interference’’ means the dis- otherwise noted. charge of sulfides in quantities which can result in human health hazards GENERAL PROVISIONS and/or risks to human life, and an inhi- bition or disruption of POTW as de- § 425.01 Applicability. fined in 40 CFR 403.3(i). This part applies to any leather tanning and finishing facility which dis- [47 FR 52870, Nov. 23, 1982, as amended at 53 charges or may discharge process FR 9181, Mar. 21, 1988] wastewater pollutants to the waters of § 425.03 Sulfide analytical methods the United States, or which introduces and applicability. or may introduce process wastewater pollutants into a publicly owned treat- (a) The potassium ferricyanide titra- ment works. tion method described in appendix A to part 425 shall be used whenever prac- § 425.02 General definitions. ticable for the determination of sulfide In addition to the definitions set in wastewaters discharged by plants forth in 40 CFR part 401, the following operating in all subcategories except definitions apply to this part: the hair save or pulp, non-chrome tan, (a) ‘‘Sulfide’’ shall mean total sulfide retan-wet finish subcategory (subpart as measured by the potassium ferricya- C, see § 425.30). In all other cases, the nide titration method described in ap- modified Monier-Williams method as pendix A or the modified Monier-Wil- described in appendix B to part 425 liams method described in appendix B. shall be used as an alternative to the (b) ‘‘Hide’’ means any animal pelt or potassium ferricyanide titration meth- skin as received by a tannery as raw od for the determination of sulfide in material to be processed. wastewaters discharged by plants oper- (c) ‘‘Retan-wet finish’’ means the ating in all subcategories except sub- final processing steps performed on a part C. tanned hide including, but not limited (b) The modified Monier-Williams to, the following wet processes: retan, method as described in appendix B to bleach, color, and fatliquor. part 425 shall be used for the deter- (d) ‘‘Hair pulp’’ means the removal of mination of sulfide in wastewaters dis- hair by chemical dissolution. charged by plants operating in the hair (e) ‘‘Hair save’’ means the physical or save or pulp, non-chrome tan, retan- mechanical removal of hair which has wet finish subcategory (subpart C, see not been chemically dissolved, and ei- § 425.30). ther selling the hair as a by-product or disposing of it as a solid waste. [53 FR 9181, Mar. 21, 1988] (f) ‘‘Chrome tan’’ means the process of converting hide into leather using a § 425.04 Applicability of sulfide form of chromium. pretreatment standards. (g) ‘‘Vegetable tan’’ means the proc- (a) A POTW receiving wastewater ess of converting hides into leather from a facility subject to this part may using chemicals either derived from require more stringent pretreatment vegetable matter or synthesized to standards for sulfide than those estab- produce effects similar to those chemi- lished by this part without EPA ap- cals. proval.

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(b) The pretreatment standards for (3) On February 10, 1984, EPA shall sulfide established by this part will not acknowledge to the POTW receipt of apply if the POTW receiving waste- any certification submitted under water from a facility subject to this paragraphs (c) (1) and (2) of this sec- part certifies in writing with expla- tion, and shall indicate to the POTW nation of relevant factors considered, the adequacy of the submission based in accordance with the provisions of upon a review of the factors set forth paragraph (c) of this section, that the in paragraph (b) of this section. discharge of sulfide from the facility (4) Within 30 days of the date of re- does not interfere with the operation of ceipt of adequate submissions under the POTW. In making this determina- paragraphs (c) (1), (2), and (3) of this tion, the POTW shall consider all rel- section, EPA shall publish a notice in evant factors including but not limited the FEDERAL REGISTER identifying to the following: those facilities to which the sulfide (1) The presence and characteristics, pretreatment standards of this part of other industrial wastewaters which shall not apply. can increase or decrease sulfide con- (5) A POTW may certify that the sul- centrations, pH, or both. fide pretreatment standards of this (2) The characteristics of the sewer/ part should not apply to a new source interceptor collection system which ei- planning to discharge into the POTW. ther minimize or enhance opportuni- This certification must be submitted ties for release of hydrogen sulfide gas. prior to the commencement of discharge, and must conform at a min- (3) The characteristics of the receiv- imum with criteria in paragraph (b) of ing POTWs headworks, preliminary this section and the general procedures and primary treatment systems, and and intervals of time contained in sludge holding and dewatering facili- paragraphs (c) (1), (2), (3), and (4) of this ties which either minimize or enhance section. opportunities for release of hydrogen (d)(1) If, after EPA and the POTW sulfide gas. have determined in accordance with (4) The occurrence of any prior sul- this section that the sulfide fide related interference as defined in pretreatment standards of this part are § 425.02(j). not applicable to specified facilities, a (c)(1) On October 13, 1983, a POTW POTW then determines that there have which intends to certify that the sul- been changed circumstances (including fide pretreatment standard should not but not limited to changes in the fac- apply must publish, in a local news- tors specified in paragraph (b) of this paper with the largest circulation, a section) which justify application of notice that presents the findings sup- the sulfide pretreatment standards, the porting this determination consistent POTW shall revoke the certification with paragraph (a) of this section. Al- submitted under paragraph (c) of this lowance for public hearing of these section. The POTW and EPA shall then findings also must be provided. The adhere to the general procedures and POTW shall identify all existing facili- time intervals contained in paragraph ties to which the sulfide pretreatment (c) of this section in order to determine standard otherwise established by this whether the sulfide pretreatment part would not apply. standards contained in this part are ap- (2) On January 11, 1984, a POTW plicable. which intends to certify that the sul- (2) If pursuant to paragraph (d)(1) of fide pretreatment standard should not this section, the sulfide pretreatment apply must file a written certification standards of this part are applicable to with the Regional Water Management a specified facility, the indirect dis- Division Director, Environmental Pro- charger shall comply with the sulfide tection Agency, in the appropriate Re- pretreatment standards no later than gional Office. This certification shall 18 months from the date of publication include the findings supporting this de- of the FEDERAL REGISTER notice identi- termination and the results of public fying the facility. comments, and public hearing(s) if (e) At any time after October 13, 1983, held. if a POTW determines that there have

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been changed circumstances (including cattle-like hides into finished leather but not limited to changes in the fac- by chemically dissolving the hide hair, tors specified in paragraph (b) of this chrome tanning, and retan-wet fin- section), it may initiate proceedings ishing. contained in paragraph (c) of this section to determine that the sulfide § 425.11 Effluent limitations rep- pretreatment standards of this part resenting the degree of effluent re- shall not be applicable. The POTW and duction attainable by the application of the best practicable control EPA shall follow the procedures and technology currently available time intervals contained in paragraph (BPT). (c) of this section to make this determination. A final determination that Except as provided in 40 CFR 125.30 the sulfide pretreatment standards are through 125.32, any existing point not applicable must be made prior to source subject to this subpart must the discharge of sulfide not in accord- achieve the following effluent limita- ance with the standards set forth in tions representing the degree of efflu- this part. ent reduction attainable by the application of the best practicable control (The information collection and reporting technology currently available (BPT): requirements contained in paragraphs (b) and (c) were approved by the Office of Man- BPT limitations agement and Budget under control number Pollutant or pollutant property Maximum for 2040–0032) Maximum for monthly aver- any 1 day age [47 FR 52870, Nov. 23, 1982; 48 FR 30117, June 30, 1983, as amended at 48 FR 31404, July 8, Kg/kkg (or pounds per 1,000 1983; 48 FR 32346, July 15, 1983; 48 FR 35649, pounds) of raw material Aug. 5, 1983; 53 FR 9181, Mar. 21, 1988] BOD5 ...... 9 .3 4 .2 § 425.05 Compliance dates. TSS ...... 13 .4 6 .1 Oil & Grease ...... 3 .9 1 .7 The compliance date for new source Total Chromium ...... 0 .24 0 .09 performance standards (NSPS) and pH ...... (1) (1) pretreatment standards for new 1 Within the range of 6.0 to 9.0 sources (PSES) is the date the new source commences discharge. The com- [53 FR 9182, Mar. 21, 1988] pliance date for BPT effluent limita- § 425.12 Effluent limitations rep- tions and guidelines and pretreatment resenting the degree of effluent re- standards for existing sources to no duction attainable by the applica- later than March 31, 1989. tion of the best conventional pollutant control technology (BCT). [53 FR 9182, Mar. 21, 1988] Except as provided in 40 CFR 125.30 § 425.06 Monitoring requirements. through 125.32, any existing point Compliance with monthly average source subject to this subpart must discharge limitations is required re- achieve the following effluent limita- gardless of the number of samples ana- tions representing the degree of efflu- lyzed and averaged. ent reduction attainable by the application of the best conventional pollut- Subpart A—Hair Pulp, Chrome ant control technology (BCT): The effluent limitations are those for BOD5. Tan, Retan-Wet Finish Sub- TSS, Oil and Grease, and pH contained category in § 425.11.

§ 425.10 Applicability; description of § 425.13 Effluent limitations rep- the hair pulp, chrome tan, retan- resenting the degree of effluent re- wet finishing subcategory. duction attainable by the applica- The provisions of this subpart are ap- tion of the best available tech- plicable to process wastewater dis- nology economically achievable charges resulting from any tannery (BAT). which, either exclusively or in addition Except as provided in 40 CFR 125.30 to other unhairing and tanning oper- through 125.32, any existing point ation, processes raw or cured cattle or source subject to this subpart must

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achieve the following effluent limita- § 425.16 Pretreatment standards for tions representing the degree of efflu- new sources (PSNS). ent reduction attainable by the appli- Except as provided in 40 CFR 403.7 cation of the best available technology and 425.04, any new source subject to economically achievable (BAT): The effluent limitations are those for Total this subpart that introduces process Chromium contained in § 425.11. wastewater pollutants into a publicly owned treatment works must comply § 425.14 New source performance with 40 CFR part 403, and achieve the standards (NSPS). pretreatment standards contained in Any new source subject to this sub- § 425.15. part must achieve the following new source performance standards (NSPS): Subpart B—Hair Save, Chrome NSPS Tan, Retan-Wet Finish Sub- Pollutant or pollutant property Maximum Maximum category for any 1 for monthly day average § 425.20 Applicability; description of the hair save, chrome tan, retan- Kg/kkg (or lb/1,000 lb) of raw material wet finish subcategory. The provisions of this subpart are ap- BOD5 ...... 6.0 2.7 TSS ...... 8.7 4.0 plicable to process wastewater dis- Oil and grease ...... 2.5 1.1 charges resulting from any tannery Total chromium ...... 0.16 0.06 pH ...... (1) (1) which processes raw or cured cattle or 1 Within the range 6.0 to 9.0. cattle-like hides into finished leather by hair save unhairing, chrome tan- [47 FR 52870, Nov. 23, 1982; 48 FR 30116, June ning, and retan-wet finishing. 30, 1983] § 425.21 Effluent limitations rep- § 425.15 Pretreatment standards for resenting the degree of effluent re- existing sources (PSES). duction attainable by the applica- (a) Except as provided in § 425.04 and tion of the best practicable control 40 CFR 403.7 and 403.13, any existing technology currently available source subject to this subpart which in- (BPT). troduces process wastewater pollutants Except as provided in 40 CFR 125.30 into a publicly owned treatment works through 125.32, any existing point must comply with 40 CFR part 403, and source subject to this subpart must achieve the following pretreatment achieve the following effluent limita- standards: tions representing the degree of efflu- PSES ent reduction attainable by the application of the best practicable control Pollutant or pollutant property Maximum Maximum for any 1 for monthly technology currently available (BPT): day average BPT limitations Milligrams per liter (mg/l) Pollutant or pollutant property Maximum for Sulfide ...... 24 ...... Maximum for monthly aver- Total chromium ...... 12 8 any 1 day age pH ...... (1) (1) Kg/kkg (or pound per 1,000 1 Not less than 7.0. lb) of raw material (b) Any existing source subject to this subpart which processes less than BOD5 ...... 8 .2 3 .7 TSS ...... 11 .8 5 .4 275 hides/day shall comply with Oil and grease ...... 3 .4 1 .5 § 425.15(a), except that the total chro- Total chromium ...... 0.21 0 .08 mium limitations contained in pH ...... (1) (1) § 425.15(a) do not apply. 1 Within the range 6.0 to 9.0. [47 FR 52870, Nov. 23, 1982; 48 FR 30116, June 30, 1983, as amended at 53 FR 9182, Mar. 21, 1988; 61 FR 35685, July 8, 1996]

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§ 425.22 Effluent limitations rep- must comply with 40 CFR part 403, and resenting the degree of effluent re- achieve the following pretreatment duction attainable by the applica- standards: tion of the best conventional pollutant control technology (BCT). PSES Except as provided in 40 CFR 125.30 Pollutant or pollutant property Maximum Maximum for any 1 for monthly through 125.32, any existing point day average source subject to this subpart must achieve the following effluent limita- Milligrams per liter (mg/l) tions representing the degree of efflu- Sulfide ...... 24 ...... ent reduction attainable by the appli- Total Chromium ...... 12 8 cation of the best conventional pollut- pH ...... (1) (1) ant control technology (BCT): The ef- 1 Not less than 7.0. fluent limitations are those for BOD5, TSS, Oil and Grease, and pH contained [47 FR 52870, Nov. 23, 1982, as amended at 61 in § 425.21. FR 35685, July 8, 1996]

§ 425.23 Effluent limitations rep- § 425.26 Pretreatment standards for resenting the degree of effluent re- new sources (PSNS). duction attainable by the applica- Except as provided in 40 CFR 403.7 tion of the best available tech- and 425.04, any new source subject to nology economically achievable (BAT). this subpart that introduces process wastewater pollutants into a publicly Except as provided in 40 CFR 125.30 owned treatment works must comply through 125.32, any existing point with 40 CFR part 403, and achieve the source subject to this subpart must pretreatment standards contained in achieve the following effluent limita- § 425.25. tions representing the degree of effluent reduction attainable by the application of the best available technology Subpart C—Hair Save or Pulp, economically achievable (BAT): The ef- Non-Chrome Tan, Retan-Wet fluent limitations are those for Total Finish Subcategory Chromium contained in § 425.21. § 425.30 Applicability; description of § 425.24 New source performance the hair save or pulp, non-chrome standards (NSPS). tan, retan-wet finish subcategory. Any new source subject to this sub- The provisions of this subpart are ap- part must achieve the following new plicable to process wastewater dis- source performance standards (NSPS): charges resulting from any tannery which processes raw or cured cattle or NSPS cattle-like hides into finished leather by hair save or pulp unhairing, vege- Pollutant or pollutant property Maximum for Maximum for any 1 day monthly aver- table tanning or alum, syntans, oils age and other agents for tanning, and Kg/kkg (or pound per 1,000 retan-wet finishing. lb) of raw material § 425.31 Effluent limitations rep- BOD5 ...... 6 .9 3 .1 TSS ...... 9 .9 4 .5 resenting the degree of effluent re- Oil and grease ...... 2 .9 1 .3 duction attainable by the applica- Total chromium ...... 0.18 0 .06 tion of the best practicable control pH ...... (1) (1) technology currently available 1 Within the range 6.0 to 9.0 (BPT). Except as provided in 40 CFR 125.30 § 425.25 Pretreatment standards for through 125.32, any existing point existing sources (PSES). source subject to this subpart must Except as provided in § 425.04 and 40 achieve the following effluent limita- CFR 403.7 and 403.13, any existing tions representing the degree of efflu- source subject to this subpart that in- ent reduction attainable by the appli- troduces process wastewater pollutants cation of the best practicable control into a publicly owned treatment works technology currently available (BPT):

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BPT limitations NSPS Pollutant or pollutant property Maximum for Pollutant or pollutant property Maximum for Maximum for monthly aver- Maximum for monthly aver- any 1 day age any 1 day age

Kg/kkg (or pounds per 1,000 Kg/kkg (or pound per 1,000 pounds) of raw material lb) of raw material

BOD5 ...... 6 .7 3 .0 BOD5 ...... 5 .9 2 .7 TSS ...... 9 .7 4 .4 TSS ...... 8 .5 3 .9 Oil & Grease ...... 2 .8 1 .3 Oil and grease ...... 2 .4 1 .1 Total Chromium ...... 0 .17 0 .06 Total chromium ...... 0.15 0 .06 pH ...... (1) (1) pH ...... (1) (1)

1 Within the range of 6.0 to 9.0 1 Within the range 6.0 to 9.0.

[47 FR 52870, Nov. 23, 1982, as amended at 53 § 425.35 Pretreatment standards for FR 9182, Mar. 21, 1988] existing sources (PSES). (a) Except as provided in § 425.04 and § 425.32 Effluent limitations representing the degree of effluent re- 40 CFR 403.7 and § 403.13, any existing duction attainable by the applica- sources subject to this subpart that in- tion of the best conventional pollut- troduces process wastewater pollutants ant control technology (BCT). into a publicly owned treatment works Except as provided in 40 CFR 125.30 must comply with 40 CFR part 403, and through 125.32, any existing point achieve the following pretreatment source subject to this subpart must standards: achieve the following effluent limita- PSES limitations tions representing the degree of efflu- Pollutant or pollutant property Maximum Maximum ent reduction attainable by the appli- for any 1 for monthly cation of the best conventional pollut- day average

ant control technology (BCT): The ef- Milligrams per liter (mg/l) fluent limitations are those for BOD5, TSS, Oil and Grease, and pH contained Sulfide ...... 24 — in § 425.31. Total Chromium ...... 12 8 pH ...... (1) (1) § 425.33 Effluent limitations rep- 1 Not less than 7.0. resenting the degree of effluent re- (b) Any existing source subject to duction attainable by the application of the best available tech- this subpart which processes less than nology economically achievable 350 hides/day shall comply with (BAT). § 425.35(a), except that the Total Chro- mium limitations contained in Except as provided in 40 CFR 125.30 § 425.35(a) do not apply. through 125.32, any existing point source subject to this subpart must [47 FR 52870, Nov. 23, 1982; 48 FR 36116, June achieve the following effluent limita- 30, 1983, as amended at 53 FR 9182, Mar. 21, tions representing the degree of efflu- 1988] ent reduction attainable by the application of the best available technology § 425.36 Pretreatment standards for new sources (PSNS). economically achievable (BAT): The effluent limitations are those for Total Except as provided in 40 CFR 403.7 Chromium contained in § 425.31. and § 425.04, any new source subject to this subpart that introduces process § 425.34 New source performance wastewater pollutants into a publicly standards (NSPS). owned treatment works must comply Any new source subject to this sub- with 40 CFR part 403, and achieve the part must achieve the following new pretreatment standards contained in source performance standards (NSPS): § 425.35.

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Subpart D—Retan-Wet Finish-Sides § 425.43 Effluent limitations rep- Subcategory resenting the degree of effluent reduction attainable by the applica- § 425.40 Applicability; description of tion of the best available tech- the retan-wet finish-sides sub- nology economically achievable category. (BAT). The provisions of this subpart are ap- Except as provided in 40 CFR 125.30 plicable to process wastewater dis- through 125.32, any existing point charges resulting from any tannery source subject to this subpart must which processes previously tanned achieve the following effluent limita- hides and skins (grain side only) into tions representing the degree of efflu- finished leather by retan-wet finishing. ent reduction attainable by the application of the best available technology § 425.41 Effluent limitations rep- economically achievable (BAT): The ef- resenting the degree of effluent re- fluent limitations are those for Total duction attainable by the applica- Chromium contained in § 425.41. tion of the best practicable control technology currently available § 425.44 New source performance (BPT). standards (NSPS). Except as provided in 40 CFR 125.30 Any new source subject to this sub- through 125.32, any existing point part must achieve the following new source subject to this subpart must source performance standards (NSPS): achieve the following effluent limitations representing the degree of efflu- NSPS ent reduction attainable by the appli- Pollutant or pollutant property Maximum Maximum cation of the best practicable control for any 1 for monthly technology currently available (BPT): day average

BPT limitations Kg/kkg (or pounds per 1,000 pounds) of raw Pollutant or pollutant property Maximum for material Maximum for monthly aver- any 1 day age BOD5 ...... 6.5 2.9 TSS ...... 9.3 4.3 Kg/kkg (or pounds per 1,000 pounds) of raw material Oil & Grease ...... 2.7 1.2 Total Chromium ...... 0.17 0.06 1 1 BOD5 ...... 8 .9 4 .0 pH ...... ( ) ( ) TSS ...... 12 .8 5 .8 1 Within the range of 6.0 to 9.0. Oil & Grease ...... 3 .7 1 .7 Total Chromium ...... 0 .23 0 .08 pH ...... (1) (1) [47 FR 52870, Nov. 23, 1982, as amended at 53 FR 9182, Mar. 21, 1988] 1 Within the range of 6.0 to 9.0. § 425.45 Pretreatment standards for [47 FR 52870, Nov. 23, 1982, as amended at 53 existing sources (PSES). FR 9182, Mar. 21, 1988] Except as provided in 40 CFR 403.7 § 425.42 Effluent limitations rep- and 403.13, any existing source subject resenting the degree of effluent re- to this subpart that introduces process duction attainable by the applica- wastewater pollutants into a publicly tion of the best conventional pollutant control technology (BCT). owned treatment works must comply with 40 CFR part 403, and achieve the Except as provided in 40 CFR 125.30 following pretreatment standards: through 125.32, any existing point source subject to this subpart must PSES achieve the following effluent limita- Pollutant or pollutant property Maximum Maximum tions representing the degree of efflu- for any 1 for monthly ent reduction attainable by the appli- day average cation of the best conventional pollut- Milligrams per liter (mg/l) ant control technology (BCT): The ef- Total Chromium ...... 19 12 fluent limitations are those for BOD5, TSS, Oil and Grease, and pH contained pH ...... (1) (1) in § 425.41. 1 Within the range 6.0 to 10.0.

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§ 425.46 Pretreatment standards for § 425.52 Effluent limitations rep- new sources (PSNS). resenting the degree of effluent reduction attainable by the applica- Except as provided in 40 CFR 403.7, tion of the best conventional pollut- any new source subject to this subpart ant control technology (BCT). that introduces process wastewater Except as provided in 40 CFR 125.30 pollutants into a publicly owned treat- through 125.32, any existing point ment works must comply with 40 CFR source subject to this subpart must part 403, and achieve the pretreatment achieve the following effluent limita- standards contained in § 425.45. tions representing the degree of effluent reduction attainable by the appli- Subpart E—No Beamhouse cation of the best conventional control Subcategory technology (BCT): The effluent limitations are those for BOD5, TSS, Oil and § 425.50 Applicability; description of Grease, and pH contained in § 425.51. the no beamhouse subcategory. The provisions of this subpart are ap- § 425.53 Effluent limitations representing the degree of effluent re- plicable to process wastewater dis- duction attainable by the applica- charges resulting from any tannery tion of the best available tech- which processes cattle hides, sheep- nology economically achievable skins, or splits (hair previously re- (BAT). moved and pickled) into finished leath- Except as provided in 40 CFR 125.30 er by chrome or non-chrome tanning, through 125.32, any existing point and retan-wet finishing. source subject to this subpart must achieve the following effluent limita- § 425.51 Effluent limitations rep- tions representing the degree of efflu- resenting the degree of effluent re- ent reduction attainable by the appli- duction attainable by the applica- cation of the best available technology tion of the best practicable control economically achievable (BAT): The ef- technology currently available fluent limitations are those for Total (BPT). Chromium contained in § 425.51 Except as provided in 40 CFR 125.30 through 125.32, any existing point § 425.54 New source performance source subject to this subpart must standards (NSPS). achieve the following effluent limita- Any new source subject to this sub- tions representing the degree of efflu- part must achieve the following new ent reduction attainable by the appli- source performance standards (NSPS): cation of the best practicable control technology currently available (BPT): NSPS Pollutant or pollutant property Maximum for Maximum for BPT limitations monthly aver- any 1 day age Pollutant or pollutant property Maximum for Maximum for any 1 day monthly aver- Kg/kkg (or pounds per 1,000 age lb) of raw material Kg/kkg (or pounds per 1,000 BOD5 ...... 5 .3 2 .4 pounds) of raw material TSS ...... 7 .7 3 .5 Oil & Grease ...... 2 .2 1 .0 BOD ...... 8 .0 3 .6 5 Total Chromium ...... 0 .14 0 .05 TSS ...... 11 .6 5 .3 pH ...... (1) (1) Oil & Grease ...... 3 .4 1 .5 Total Chromium ...... 0 .21 0 .08 1 Within the range 6.0 to 9.0. pH ...... (1) (1)

1 § 425.55 Pretreatment standards for Within the range of 6.0 to 9.0. existing sources (PSES). [47 FR 52870, Nov. 23, 1982, as amended at 53 Except as provided in 40 CFR 403.7 FR 9182, Mar. 21, 1988] and 403.13, any existing source subject to this subpart that introduces process wastewater pollutants into a publicly owned treatment works must comply

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with 40 CFR part 403, and achieve the BPT limitations following pretreatment standards: Pollutant or pollutant property Maximum for Maximum for any 1 day monthly aver- PSES age

Pollutant or pollutant property Maximum Maximum Kg/kkg (or pounds per 1,000 for any 1 for monthly pounds) of raw material day average

Milligrams per liter (mg/l) BOD5 ...... 3 .2 1 .5 TSS ...... 4 .7 2 .1 Total chromium ...... 19 12 Oil & Grease ...... 1 .4 0 .61 pH ...... (1) (1) Total Chromium ...... 0 .08 0 .03 pH ...... (1) (1) 1 Within the range 6.0 to 10.0. 1 Within the range of 6.0 to 9.0. § 425.56 Pretreatment standards for new sources (PSNS). [47 FR 52870, Nov. 23, 1982, as amended at 53 FR 9183, Mar. 21, 1988] Except as provided in 40 CFR 403.7, any new source subject to this subpart § 425.62 Effluent limitations rep- that introduces process wastewater resenting the degree of effluent re- pollutants into a publicly owned treat- duction attainable by the applica- ment works must comply with 40 CFR tion of the best conventional pollut- part 403, and achieve the pretreatment ant control technology (BCT). standards contained in § 425.55. Except as provided in 40 CFR 125.30 through 125.32, any existing point Subpart F—Through-the-Blue source subject to this subpart must Subcategory achieve the following effluent limitations representing the degree of efflu- § 425.60 Applicability; description of ent reduction attainable by the appli- the through-the-blue subcategory. cation of the best conventional pollut- The provisions of this subpart are ap- ant control technology (BCT): The ef- plicable to process wastewater dis- fluent limitations are those for BOD5, charges resulting from any tannery TSS, Oil and Grease, and pH contained which processes raw or cured cattle or in § 425.61. cattle-like hides through the blue § 425.63 Effluent limitations rep- tanned state by hair pulp unhairing resenting the degree of effluent re- and chrome tanning; no retan-wet fin- duction attainable by the applica- ishing is performed. tion of the best available technology economically achievable § 425.61 Effluent limitations rep- (BAT). resenting the degree of effluent reduction attainable by the applica- Except as provided in 40 CFR 125.30 tion of the best practicable control through 125.32, any existing point technology currently available source subject to this subpart must (BPT). achieve the following effluent limita- Except as provided in 40 CFR 125.30 tions representing the degree of efflu- through 125.32, any existing point ent reduction attainable by the appli- source subject to this subpart must cation of the best available technology achieve the following effluent limita- economically achievable (BAT): The ef- tions representing the degree of efflu- fluent limitations are those for Total ent reduction attainable by the appli- Chromium contained in § 425.61. cation of the best practicable control § 425.64 New source performance technology currently available (BPT): standards (NSPS). Any new source subject to this subpart must achieve the following new source performance standards (NSPS):

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BPT limitations sheep-like skins with the wool or hair retained into finished leather by Pollutant or pollutant property Maximum for Maximum for chrome tanning, and retan-wet fin- any 1 day monthly average ishing. Kg/kkg (or pounds per 1,000 pounds) of raw material § 425.71 Effluent limitations representing the degree of effluent re- BOD5 ...... 3 .2 1 .5 duction attainable by the applica- TSS ...... 4 .7 2 .1 tion of the best practicable control Oil & Grease ...... 1 .4 0 .61 Total Chromium ...... 0 .08 0 .03 technology currently available pH ...... (1) (1) (BPT). 1 Within the range of 6.0 to 9.0. Except as provided in 40 CFR 125.30 through 125.32, any existing point [47 FR 52870, Nov. 23, 1982, as amended at 53 source subject to this subpart must FR 9183, Mar. 21, 1988] achieve the following effluent limitations representing the degree of efflu- § 425.65 Pretreatment standards for existing sources (PSES). ent reduction attainable by the application of the best practicable control Except as provided in § 425.04 and 40 technology currently available (BPT): CFR 403.7 and 403.13, any existing source subject to this subpart that in- NSPS troduces process wastewater pollutants Pollutant or pollutant property Maximum for Maximum for into a publicly owned treatment works any 1 day monthly aver- must comply with 40 CFR part 403, and age achieve the following pretreatment Kg/kkg (or pounds per 1,000 standards: pounds) of raw material

PSES BOD5 ...... 3 .0 1 .3 TSS ...... 4 .3 1 .9 Pollutant or pollutant property Maximum for Maximum for Oil & Grease ...... 1 .2 0 .55 monthly aver- Total Chromium ...... 0 .08 0 .03 any 1 day age pH ...... (1) (1) Milligrams per liter (mg/l) 1 Within the range of 6.0 to 9.0. Sulfide ...... 24 ...... Total chromium ...... 12 8 [47 FR 52870, Nov. 23, 1982, as amended at 53 pH ...... (1) (1) FR 9183, Mar. 21, 1988]

1 Not less than 7.0. § 425.72 Effluent limitations rep- [47 FR 52870, Nov. 23, 1982, as amended at 61 resenting the degree of effluent re- FR 35685, July 8, 1996] duction attainable by the application of the best conventional pollut- § 425.66 Pretreatment standards for ant control technology (BCT). new sources (PSNS). Except as provided in 40 CFR 125.30 Except as provided in 40 CFR 403.7 through 125.32, any existing point and 425.04, any new source subject to source subject to this subpart must this subpart that introduces process achieve the following effluent limita- wastewater pollutants into a publicly tions representing the degree of efflu- owned treatment must comply with 40 ent reduction attainable by the appli- CFR part 403, and must achieve the cation of the best conventional pollut- pretreatment standards contained in ant control technology (BCT): The ef- § 425.65. fluent limitations are those for BOD5, TSS, Oil and Grease, and pH contained Subpart G—Shearling in § 425.71. Subcategory § 425.73 Effluent limitations representing the degree of effluent re- § 425.70 Applicability; description of duction attainable by the applica- the shearling subcategory. tion of the best available tech- The provisions of this subpart are ap- nology economically achievable plicable to process wastewater dis- (BAT). charges resulting from any tannery Except as provided in 40 CFR 125.30 which processes raw or cured sheep or through 125.32, any existing point

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source subject to this subpart must Subpart H—Pigskin Subcategory achieve the following effluent limitations representing the degree of efflu- § 425.80 Applicability; description of ent reduction attainable by the appli- the pigskin subcategory. cation of the best available technology The provisions of this subpart are ap- economically achievable (BAT): The ef- plicable to process wastewater dis- fluent limitations are those for Total charges resulting from any tannery Chromium contained in § 425.71. which processes raw or cured pigskins into finished leather by chemically dis- § 425.74 New source performance solving or pulping the hair and tanning standards (NSPS). with chrome, then retan-wet finishing. Any new source subject to this subpart must achieve the following new § 425.81 Effluent limitations rep- source performance standards (NSPS): resenting the degree of effluent reduction attainable by the applica- NSPS tion of the best practicable control technology currently available Pollutant or pollutant property Maximum for Maximum for (BPT). any 1 day monthly average Except as provided in 40 CFR 125.30 Kg/kkg (or pound per 1,000 through 125.32, any existing point lb) of raw material source subject to this subpart must achieve the following effluent limita- BOD5 ...... 13 .2 5 .9 TSS ...... 19 .1 8 .7 tions representing the degree of efflu- Oil and grease ...... 5 .6 2 .5 ent reduction attainable by the appli- Total chromium ...... 0.34 0 .12 cation of the best practicable control pH ...... (1) (1) technology currently available (BPT): 1 Within the range 6.0 to 9.0. BPT limitations § 425.75 Pretreatment standards for Pollutant or pollutant property Maximum for Maximum for monthly aver- existing sources (PSES). any 1 day age Except as provided in 40 CFR 403.7 Kg/kkg (or pounds per 1,000 and 403.13, any existing source subject lb) of raw material to this subpart that introduces process wastewater pollutants into a publicly BOD5 ...... 7 .0 3 .2 owned treatment works must comply TSS ...... 10 .1 4 .6 Oil and grease ...... 3 .0 1 .3 with 40 CFR part 403, and achieve the Total chromium ...... 0.18 0 .07 following pretreatment standards: pH ...... (1) (1)

PSES 1 Within the range 6.0 to 9.0.

Pollutant or pollutant property Maximum Maximum [47 FR 52870, Nov. 23, 1982; 48 FR 30117, June for any 1 for monthly day average 30, 1983]

Milligrams per liter (mg/l) § 425.82 Effluent limitations representing the degree of effluent re- Total chromium ...... 19 12 1 1 duction attainable by the applica- pH ...... ( ) ( ) tion of the best conventional pollut- 1 Within the range 6.0 to 10.0. ant control technology (BCT). Except as provided in 40 CFR 125.30 § 425.76 Pretreatment standards for new sources (PSNS). through 125.32, any existing point source subject to this subpart must Except as provided in 40 CFR 403.7, achieve the following effluent limita- any new source subject to this subpart tions representing the degree of efflu- that introduces process wastewater ent reduction attainable by the appli- pollutants into a publicly owned treat- cation of the best conventional pollut- ment works must comply with 40 CFR ant control technology (BCT): The ef- part 403, and must achieve the fluent limitations are those for BOD5, pretreatment standards contained in TSS, Oil and Grease and pH contained § 425.75. in § 425.81.

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§ 425.83 Effluent limitations rep- § 425.86 Pretreatment standards for resenting the degree of effluent re- new sources (PSNS). duction attainable by the application of the best available tech- Except as provided in 40 CFR 403.7 nology economically achievable and 425.04, any new source subject to (BAT). this subpart that introduces process Except as provided in 40 CFR 125.30 wastewater pollutants into a publicly through 125.32, any existing point owned treatment works must comply source subject to this subpart must with 40 CFR part 403, and achieve the achieve the following effluent limita- pretreatment standards contained in tions representing the degree of efflu- § 425.85. ent reduction attainable by the application of the best available technology Subpart I—Retan-Wet Finish-Splits economically achievable (BAT): The ef- Subcategory fluent limitations are those for Total Chromium contained in § 425.81. § 425.90 Applicability; description of the retan-wet finish-splits sub- § 425.84 New source performance category. standards (NSPS). The provisions of this subpart are ap- Any new source subject to this sub- plicable to process wastewater dis- part must achieve the following new charges resulting from any tannery source performance standards (NSPS): which processes previously unhaired NSPS and tanned splits into finished leather by retan-wet finishing. Pollutant or pollutant property Maximum for Maximum for any 1 day monthly average § 425.91 Effluent limitations rep- Kg/kkg (or pounds per 1,000 resenting the degree of effluent re- lb) of raw material duction attainable by the application of the best practicable control BOD5 ...... 5 .8 2 .6 technology currently available TSS ...... 8 .3 3 .8 (BPT). Oil and grease ...... 2 .4 1 .1 Total chromium ...... 0.15 0 .05 Except as provided in 40 CFR 125.30 pH ...... (1) (1) through 125.32, any existing point 1 Within the range 6.0 to 9.0. source subject to this subpart must achieve the following effluent limita- § 425.85 Pretreatment standards for existing sources (PSES). tions representing the degree of effluent reduction attainable by the appli- Except as provided in § 425.04 and 40 cation of the best practicable control CFR 403.7 and § 403.13, any existing technology currently available (BPT): source subject to this subpart that introduces process wastewater pollutants BPT limitations into a publicly owned treatment works Pollutant or pollutant property Maximum for must comply with 40 CFR part 403, and Maximum for any 1 day monthly aver- achieve the following pretreatment age standards: Kg/kkg (or pounds per 1,000 pounds) of raw material PSES Pollutant or pollutant property Maximum Maximum BOD5 ...... 5 .8 2 .6 for any 1 for monthly TSS ...... 8 .3 3 .8 day average Oil & Grease ...... 2 .4 1 .1 Total Chromium ...... 0 .15 0 .05 Milligrams per liter (mg/l) pH ...... (1) (1)

Sulfide ...... 24 ...... 1 Within the range of 6.0 to 9.0. Total chromium ...... 12 8 pH ...... (1) (1) [47 FR 52870, Nov. 23, 1982, as amended at 53 1 Not less than 7.0. FR 9183, Mar. 21, 1988]

[47 FR 52870, Nov. 23, 1982, as amended at 61 FR 35685, July 8, 1996]

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§ 425.92 Effluent limitations rep- with 40 CFR part 403, and must achieve resenting the degree of effluent re- the following pretreatment standards: duction attainable by the application of the best conventional pollut- PSES ant control technology (BCT). Pollutant or pollutant property Maximum Maximum for any 1 for monthly Except as provided in 40 CFR 125.30 day average through 125.32, any existing point source subject to this subpart must Milligrams per liter (mg/l) achieve the following effluent limita- Total Chromium ...... 19 12 tions representing the degree of efflu- pH ...... (1) (1) ent reduction attainable by the appli- 1 Within the range 6.0 to 10.0. cation of the best conventional pollut- (b) Any existing source subject to ant control technology (BCT): The ef- this subpart which processes less than fluent limitations are those for BOD , 5 3,600 splits/day shall comply with TSS, Oil and Grease, and pH contained § 425.95(a), except that the total chro- in § 425.91. mium limitations contained in § 425.93 Effluent limitations rep- § 425.95(a) do not apply. resenting the degree of effluent re- [47 FR 52870, Nov. 23, 1982; 48 FR 30117, June duction attainable by the applica- 30, 1983, as amended at 53 FR 9183, Mar. 21, tion of the best available tech- 1988] nology economically achievable (BAT). § 425.96 Pretreatment standards for Except as provided in 40 CFR 125.30 new sources (PSNS). through 125.32, any existing point Except as provided in 40 CFR 403.7, source subject to this subpart must any new source subject to this subpart achieve the following effluent limita- that introduces process wastewater tions representing the degree of efflu- pollutants into a publicly owned treat- ent reduction attainable by the appli- ment works must comply with 40 CFR cation of the best available technology part 403, and achieve the pretreatment economically achievable (BAT): The ef- standards contained in § 425.95. fluent limitations are those for Total Chromium contained in § 425.91. APPENDIX A TO PART 425—POTASSIUM FERRICYANIDE TITRATION METHOD § 425.94 New source performance standards (NSPS). Source Any new source subject to this sub- The potassium ferricyanide titration method is based on method SLM 4/2 de- part must achieve the following new scribed in ‘‘Official Method of Analysis,’’ So- source performance standards (NSPS): ciety of Leather Trades’ Chemists, Fourth Revised Edition, Redbourn, Herts., England, NSPS 1965. Pollutant or pollutant property Maximum for Maximum for monthly aver- Outline of Method any 1 day age The buffered sulfide solution is titrated Kg/kkg (or pounds per 1,000 with standard potassium ferricyanide solu- lb) of raw material tion in the presence of a ferrous dimethylglyoxime ammonia complex. The BOD5 ...... 3 .5 1 .6 sulfide is oxidized to sulfur. Sulfite inter- TSS ...... 5 .1 2 .3 Oil & Grease ...... 1 .5 0 .66 feres and must be precipitated with barium Total Chromium ...... 0 .09 0 .03 chloride. Thiosulfate is not titrated under pH ...... (1) (1) the conditions of the determination (Charlot, ‘‘Ann. chim, anal,’’, 1945, 27, 153; Booth; ‘‘J. 1 Within the range 6.0 to 9.0. Soc. Leather Trades’ Chemists,’’ 1956, 40, § 425.95 Pretreatment standards for 238). existing sources (PSES). Apparatus (a) Except as provided in 40 CFR 403.7 Burrette, 10 ml. and 403.13, any existing source subject to this subpart that introduces process Reagents wastewater pollutants into a publicly 1. Preparation of 0.02N potassium ferricya- owned treatment works must comply nide; Weigh to the nearest tenth of a gram

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6.6 g. of analytical reagent grade potassium sulfate solution, and titrate the mixture con- ferricyanide and dissolve in 1 liter distilled taining the gelatinous precipitate with water. Store in an amber bottle in the dark. standardized sodium thiosulfate or Prepare fresh each week. phenylarsine oxide titrant in the range of 2. Standardization of ferricyanide solution: 0.025–0.050N Add 1 ml. of starch indicator so- Transfer 50 ml. of solution to a 250 ml. Erlen- lution after the color has faded to a pale yel- meyer flask. Add several crystals of potas- low, and continue the titration to the dis- sium iodide (about 1 g.), mix gently to disappearance of the blue color. Calculate the solve, add 1 ml. of 6N hydrochloric acid, stop- normality of the ferricyanide solution using per the flask, and swirl gently. Let stand for the equation: two minutes, add 10 ml. of a 30 percent zinc

3. Preparation of 6M ammonium chloride 4 or equivalent) immediately after collec- buffer, pH 9.3: Dissolve 200 g. ammonium tion. Filtered samples must be preserved by chloride in approximately 500 ml. distilled adjustment to pH>12 with 10N NaOH. Sample water, add 200 ml. 14M reagent grade ammo- containers must be covered tightly and nium hydroxide and make up to 1 liter with stored at 4 °C until analysis. Samples must distilled water. The buffer should be pre- be analyzed within 48 hours of collection. If pared in a hood. Store in a tightly stoppered these procedures cannot be achieved, it is container. the laboratory’s responsibility to institute 4. Preparation of 0.05M barium chloride so- quality control procedures that will provide lution: Dissolve 12–13 g. barium chloride di- hydrate in 1 liter of distilled water. documentation of sample integrity. 5. Preparation of ferrous dimethylglyoxime Procedure indicator solution: Mix 10 ml. 0.6 percent ferrous sulfate, 50 ml. 1 percent 1. Transfer 100 ml. of sample to be ana- dimethylglyoxime in ethanol, and 0.5 ml. lyzed, or a suitable portion containing not concentrated sulfuric acid. more than 15 mg. sulfide supplemented to 100 6. Preparation of stock sulfide standard, ml. with distilled water, to a 250 ml. Erlen- 1000 ppm: Dissolve 2.4 g. reagent grade so- meyer flask. dium sulfide in 1 liter of distilled water. 2. Adjust the sample to pH 8.5–9.5 with 6N Store in a tightly stoppered container. Di- HC1. luted working standards must be prepared fresh daily and their concentrations deter- 3. Add 20 ml. of 6M ammonium chloride mined by EPA test procedure 376.1 (see 40 buffer (pH 9.3), 1 ml. of ferrous CFR 136.3, Table IB, parameter 66 (49 FR dimethylglyoxime indicator, and 25 ml. of 43234, October 26, 1984, with correction notice 0.05M barium chloride. Mix gently, stopper, at 50 FR 690, January 4, 1985)) immediately and let stand for 10 minutes. prior to use. 4. After 10 minutes titrate with standard- 7. Preparation of 10N NaOH: Dissolve 400 g. ized potassium ferricyanide to disappearance of analytical reagent grade NaOH in 1 liter of pink color. The endpoint is reached when distilled water. there is no reappearance of the pink color after 30 seconds. Sample Preservation and Storage Samples are to be field filtered (gravity or Calculation and Reporting of Results. pressure) with coarse filter paper (Whatman

where A = volume in ml. of potassium ferri- 2. Report results to two significant figures. cyanide solution used, and B = normality of potassium ferricyanide solution.

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Quality Control lytical event, or five percent spikes and five percent duplicates when the number of sam- 1. Each laboratory that uses this method is ples per event exceeds twenty. Spike levels required to operate a formal quality control are to be at the MDL (see paragraph 3 above program. The minimum requirements of this for MDL samples) and at x where x is the program consist of an initial demonstration concentration found if in excess of the MDL. of laboratory capability and the analysis of Spike recovery must be 40 to 120 percent for replicate and spiked samples as a continuing the analysis of a particular matrix type to be check on performance. The laboratory is re- considered valid. If a sample or matrix type quired to maintain performance records to provides performance outside these accept- define the quality of data that is generated. ance limits, the analyses must be repeated Ongoing performance checks must be com- using the modified Monier-Williams proce- pared with established performance criteria dures described in appendix B to this part. to determine if the results of analyses are within precision and accuracy limits ex- 5. Report results in mg./liter. When dupli- pected of the method. cate and spiked samples are analyzed, report 2. Before performing any analyses, the ana- all data with the sample results. lyst must demonstrate the ability to gen- [53 FR 9183, Mar. 21, 1988] erate acceptable precision and accuracy with this method by performing the following op- APPENDIX B TO PART 425—MODIFIED erations. MONIER-WILLIAMS METHOD (a) Perform four replicate analyses of a 20 mg./l. sulfide standard prepared in distilled Outline of Method water (see paragraph 6 under ‘‘Reagents’’ above). Hydrogen sulfide is liberated from an (b)(1) Calculate clean water precision and acidified sample by distillation and purging accuracy in accordance with standard statis- with nitrogen gas (N2). Sulfur dioxide inter- tical procedures. Clean water acceptance ference is removed by scrubbing the nitrogen limits are presented in paragraph 2(b)(2) gas stream in a pH 7 buffer solution. The sul- below. These criteria must be met or exceed- fide gas is collected by passage through an ed before sample analyses can be initiated. A alkaline hydrogen peroxide scrubbing solu- clean water standard must be analyzed with tion in which it is oxidized to sulfate. Sul- each sample set and the established criteria fate concentration in the scrubbing solution met for the analysis to be considered under is determined by either EPA gravimetric control. test procedure 375.3 or EPA turbidimetric (2) Clean water precision and accuracy ac- test procedure 375.4 (see 40 CFR 136.3, Table ceptance limits: For distilled water samples IB, parameter 65 (49 FR 43234, October 26, containing from 5 mg./l. to 50 mg./l. sulfide, 1984, and correction notice at 50 FR 690, Jan- the mean concentration from four replicate uary 4, 1985)). analyses must be within the range of 50 to Apparatus* 110 percent of the true value. 3. The Method Detection Limits (MDL) (See Figure 1.) * Catalogue numbers are should be determined periodically by each given only to provide a more complete de- participating laboratory in accordance with scription of the equipment necessary, and do the procedures specified in ‘‘Methods for not constitute a manufacturer or vendor en- Chemical Analysis of Municipal and Indus- dorsement. trial Wastewater,’’ EPA–660/4–82–057, July Heating mantel and control (VWR Cat. No. 1982, EMSL, Cincinnati, OH 45268. For the 33752–464) convenience of the user, these procedures are 1000 ml. distilling flask with three 24/40 contained in appendix C to part 425. joints (VWR Cat. No. 29280–215) 4. A minimum of one spiked and one dupli- Friedricks condenser with two 24/40 joints cate sample must be performed for each ana- (VWR Cat. No. 23161–009)

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125 ml. separatory funnel with 24/40 joint 3. Sodium hydroxide, 0.03N: Dilute 5.0 ml. (VWR Cat. No. 30357–102) of 6N NaOH to 1 liter with distilled water. Inlet tube with 24/40 joint (VWR Cat. No. 4. Hydrochloric acid, 6N: Dilute 500 ml. of 33057–105) concentrated HCl to 1 liter with distilled Adapter joint 24/40 to 19/38 (VWR Cat. No. water. 62905–26) 5. Potassium phosphate stock buffer, 0.5M: Adsorber head (2 required) (Thomas Cat. No. Dissolve 70 g. of monobasic potassium phos- 9849–R29) phate in approximately 800 ml. distilled Adsorber body (2 required) (Thomas Cat. No. water. Adjust pH to 7.0 ±0.1 with 6N potas- 9849–R32) sium hydroxide and dilute to 1 liter with dis- Laboratory vacuum pump or water aspirator tilled water. Stock solution in stable for several months at 4 °C. Reagents 6. Potassium phosphate buffer, 0.05M: Di- 1. Potassium hydroxide, 6N: Dissolve 340 g. lute 1 volume of 0.5M potassium phosphate of analytical reagent grade KOH in 1 liter stock buffer with 9 volumes of distilled distilled water. water. Solution is stable for one month at 4 2. Sodium hydroxide, 6N: Dissolve 240 g. of °C. analytical reagent grade NaOH in 1 liter dis- 7. Alkaline 3% hydrogen peroxide: Dilute 1 tilled water. volume of 30 percent hydrogen peroxide with

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9 volumes of 0.03N NaOH. Prepare this solu- frothing vigorously, but not overflowing. tion fresh each day of use. Vaccum may be applied at the outlet of Trap 8. Preparation of stock sulfide standard, No. 2 to assist in smooth purging. The N2 1000 ppm.: Dissolve 2.4 g. reagent grade so- inlet tube of the distillation flask must be dium sulfide in 1 liter of distilled water. submerged deeply in the sample to ensure ef- Store in a tightly stoppered container. Di- ficient agitation. Purge the sample for 30 luted working standards must be prepared minutes without applying heat. Test the ap- fresh daily and their concentrations deter- paratus for leaks during the prepurge cycle mined by EPA test procedure 376.1 imme- (Snoop or soap water solution). diately prior to use (see 40 CFR 136.3, Table 4. Volatilization of H2 S: Interrupt the N2 IB, parameter 66 (49 FR 43234, October 26, flow (and vacuum) and introduce 100 ml. of 1984, and correction notice at 50 FR 690, Jan- 6N HCl to the sample using the separatory uary 4, 1985)). funnel. Immediately resume the gas flow Sample Preservation and Storage (and vacuum). Apply maximum heat with the heating mantle until the sample begins Preserve unfiltered wastewater samples to boil, then reduce heat and maintain immediately after collection by adjustment gentle boiling and N2 flow for 30 minutes. to pH>9 with 6N NaOH and addition of 2 ml. Terminate the distillation cycle by turning of 2N zinc acetate per liter. This amount of off the heating mantle and maintaining N2 zinc acetate is adequate to preserve 64 mg./l. flow through the system for 5 to 10 minutes. sulfide under ideal conditions. Sample con- Then turn off the N2 flow (and release vacu- tainers must be covered tightly and stored at um) and cautiously vent the system by plac- ° 4 C until analysis. Samples must be ana- ing 50 to 100 ml. of distilled water in the lyzed within seven days of collection. If separatory funnel and opening the stopcock these procedures cannot be achieved, it is carefully. When the bubbling stops and the the laboratory’s responsibility to institute system is equalized to atmospheric pressure, quality control procedures that will provide remove the separatory funnel. Extreme care documentation of sample integrity. must be exercised in terminating the dis- Procedure (See Figure 1 for apparatus layout.) tillation cycle to avoid flash-over, draw- back, or violent steam release. 1. Place 50 ml. of 0.05M pH 7.0 potassium 5. Analysis: Analyze the contents of Trap phosphate buffer in Trap No. 1. No. 2 for sulfate according to either EPA 2. Place 50 ml. of alkaline 3 percent hydro- gravimetric test procedure 375.3 or EPA tur- gen peroxide in Trap No. 2. bidimetric test procedure 375.4 (see 40 CFR 3. Sample introduction and N prepurge: 2 136.3, Table IB, parameter 65 (49 FR 43234, Oc- Gently mix sample to be analyzed to resus- tober 26, 1984, and correction notice at 50 FR pend settled material, taking care not to 690, January 4, 1985)). Use the result to cal- aerate the sample. Transfer 400 ml. of sam- culate mg./l. of sulfide in wastewater sample. ple, or a suitable portion containing not more than 20 mg. sulfide diluted to 400 ml. Calculations and Reporting of Results with distilled water, to the distillation flask. Adjust the N2 flow so that the impingers are 1. Gravimetric procedure:

2. Turbidimetric procedure: program. The minimum requirements of this program consist of an initial demonstration of laboratory capability and the analysis of replicate and spiked samples as a continuing check on performance. The laboratory is re- where A = mg./l. of sulfate in Trap No. 2 quired to maintain performance records to B = liquid volume in liters in Trap No. 2 define the quality of data that is generated. and C = volume in ml. of waste sample dis- Ongoing performance checks must be com- tilled pared with established performance criteria to determine if the results of analyses are 3. Report results to two significant figures. within precision and accuracy limits ex- Quality Control pected of the method. 1. Each laboratory that uses this method is required to operate a formal quality control

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2. Before performing any analyses, the ana- zero and determined from analysis of a sam- lyst must demonstrate the ability to gen- ple in a given matrix containing analyte. erate acceptable accuracy and precision by performing the following operations. Scope and Application (a) Perform four replicate analyses of a 20 This procedure is designed for applicability mg./l. sulfide standard prepared in distilled to a wide variety of sample types ranging water (see paragraph 8 under ‘‘Reagents’’ from reagent (blank) water containing above). analyte to wastewater containing analyte. (b)(1) Calculate clean water precision and The MDL for an analytical procedure may accuracy in accordance with standard statis- vary as a function of sample type. The proce- tical procedures. Clean water acceptance dure requires a complete, specific and well limits are presented in paragraph 2(b)(2) defined analytical method. It is essential below. These criteria must be met or exceed- that all sample processing steps of the ana- ed before sample analyses can be initiated. A lytical method be included in the determina- clean water standard must be analyzed with tion of the method detection limit. each sample set and the established criteria The MDL obtained by this procedure is met for the analyses to be considered under used to judge the significance of a single control. measurement of a future sample. (2) Clean water precision and accuracy ac- The MDL procedure was designed for appli- ceptance limits: For distilled water samples cability to a broad variety of physical and containing from 5 mg./l. to 50 mg./l. sulfide, chemical methods. To accomplish this, the the mean concentration from four replicate procedure was made device- or instrument- analyses must be within the range of 72 to independent. 114 percent of the true value. Procedure 3. The Method Detection Limit (MDL) should be determined periodically by each 1. Make an estimate of the detection limit participating laboratory in accordance with using one of the following: the procedures specified in ‘‘Methods for (a) The concentration value that cor- Chemical Analysis of Municipal and Indus- responds to an instrument signal/noise ratio trial Wastewater,’’ EPA–600/4–82–057, July in the range of 2.5 to 5. If the criteria for 1982, EMSL, Cincinnati, OH 45268. For the qualitative identification of the analyte is convenience of the user, these procedures are based upon pattern recognition techniques, contained in appendix C to part 425. the least abundant signal necessary to 4. A minimum of one spiked and one dupli- achieve identification must be considered in cate sample must be run for each analytical making the estimate. event, or five percent spikes and five percent (b) The concentration value that cor- duplicates when the number of samples per responds to three times the standard devi- event exceeds twenty. Spike levels are to be ation of replicate instrumental measure- at the MDL (see paragraph 3 above for MDL ments for the analyte in reagent water. samples) and at x when x is the concentra- (c) The concentration value that cor- tion found if in excess of the MDL. Spike re- responds to the region of the standard curve covery must be 60 to 120 percent for the anal- where there is a significant change in sensi- ysis of a particular matrix type to be consid- tivity at low analyte concentrations, i.e., a ered valid. break in the slope of the standard curve. (d) The concentration value that cor- 5. Report all results in mg./liter. When du- responds to known instrumental limitations. plicate and spiked samples are analyzed, re- It is recognized that the experience of the port all data with the sample results. analyst is important to this process. How- [53 FR 9184, Mar. 21, 1988] ever, the analyst must include the above considerations in the estimate of the detec- APPENDIX C TO PART 425—DEFINITION tion limit. AND PROCEDURE FOR THE DETER- 2. Prepare reagent (blank) water that is as MINATION OF THE METHOD DETEC- free of analyte as possible. Reagent or interference free water is defined as a water sam- TION LIMIT 1 ple in which analyte and interferent con- The method detection limit (MDL) is de- centrations are not detected at the method fined at the minimum concentration of a detection limit of each analyte of interest. substance that can be identified, measured Interferences are defined as systematic er- and reported with 99 percent confidence that rors in the measured analytical signal of an the analyte concentration is greater than established procedure caused by the presence of interfering species (interferent). The interferent concentration is presupposed to 1 Source: ‘‘Methods for Chemical Analysis be normally distributed in representative of Municipal and Industrial Wastewater,’’ samples of a given matrix. EPA–600/4–82–057, July 1982, EMSL, Cin- 3. (a) If the MDL is to be determined in re- cinnati, OH 45268 agent water (blank), prepare a laboratory

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standard (analyte in reagent water) at a con- aliquots and proceed. Use all seven measure- centration which is at least equal to or in ments to calculate the MDL. the same concentration range as the esti- (2) If these measurements indicate the mated MDL. (Recommended between 1 and 5 sample is not in the correct range, reesti- times the estimated MDL.) Proceed to Step mate the MDL, obtain new sample as in 3 4. and repeat either 4a or 4b. (b) If the MDL is to be determined in an- 5. Calculate the variance (S2) and standard other sample matrix, analyze the sample. If deviation (S) of the replicate measurements, the measured level of the analyte is in the as follows: recommended range of one to five times the estimated MDL, proceed to Step 4. ⎡ 2 ⎤ n ⎛ n ⎞ If the measured concentration of analyte is ⎢ ⎥ 2 = 1 2 − ⎜ ⎟ less than the estimated MDL, add a known SXX⎢∑ i ∑ i / n⎥ n −1 ⎢ ⎜ ⎟ ⎥ amount of analyte to bring the concentra- i=1 ⎝ i=1 ⎠ tion of analyte to between one and five times ⎣ ⎦ the MDL. In the case where an interference 2 05. is coanalyzed with the analyte: S=() S If the measured level of analyte is greater than five times the estimated MDL, there where: the xi, i = 1 to n are the analytical re- are two options: sults in the final method reporting units obtained from the n sample aliquots and (1) Obtain another sample of lower level of analyte in same matrix if possible. n (2) The sample may be used as is for deter- 2 mining the MDL if the analyte level does not ∑ Xi exceed 10 times the MDL of the analyte in reagent water. The variance of the analyt- i=1 ical method changes as the analyte con- refers to the sum of the X values from i = 1 centration increases from the MDL, hence to n. the MDL determined under these cir- 6. (a) Compute the MDL as follows: cumstances may not truly reflect method MDL = t( ¥ ¥ = ) (S) variance at lower analyte concentrations. n 1,1 a .99 4. (a) Take a minimum of seven aliquots of where: the sample to be used to calculate the MDL MDL = the method detection and process each through the entire t (n-1, 1-a = .99) = the students’ t value appro- anlaytical method. Make all computations priate for a 99 percent confidence level according to the defined method with final and a standard deviation estimate with results in the method reporting units. If n-1 degrees of freedom. See Table. blank measurements are required to cal- S = standard deviation of the replicate anal- culate the measured level of analyte, obtain yses. separate blank measurements for each sam- (b) The 95 percent confidence limits for the ple aliquot anlayzed. The average blank MDL derived in 6a are computed according measurement is subtracted from the respec- to the following equations derived from per- tive sample measurements. centiles of the chi square over degrees of (b) It may be economically and technically freedom distribution (X2/df) and calculated desirable to evaluate the estimated MDL be- as follows: fore proceeding with 4a. This will: (1) Pre- MDL = 0.69 MDL vent repeating this entire procedure when LCL the costs of analyses are high and (2) insure MDLUCL = 1.92 MDL where MDLLCL and that the procedure is being conducted at the MDLUCL are the lower and upper 95 per- correct concentration. It is quite possible cent confidence limits respectively based that an incorrect MDL can be calculated on seven aliquots. from data obtained at many times the real 7. Optional iterative procedure to verify MDL even though the background concentra- the reasonableness of the estimated MDL tion of analyte is less than five times the and calculated MDL of subsequent MDL de- calculated MDL. To insure that the estimate terminations. of the MDL is a good estimate, it is nec- (a) If this is the initial attempt to compute essary to determine that a lower concentra- MDL based on the estimated MDL in Step 1, tion of analyte will not result in a signifi- take the MDL as calculated in Step 6, spike cantly lower MDL. Take two aliquots of the in the matrix at the calculated MDL and sample to be used to calculate the MDL and proceed through the procedure starting with process each through the entire method, in- Step 4. cluding blank measurements as described (b) If the current MDL determination is an above in 4a. Evaluate these data: iteration of the MDL procedure for which the (1) If these measurements indicate the spiking level does not permit qualitative sample is in the desirable range for deter- identification, report the MDL as that con- mining the MDL, take five additional centration between the current spike level

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and the previous spike level which allows If the level of the analyte in the sample qualitative identification. matrix exceeds 10 times the MDL of the (c) If the current MDL determination is an analyte in reagent water, do not report a iteration of the MDL procedure and the spik- value for the MDL. ing level allows qualitative identification, use S2 from the current MDL calculation and REFERENCE 2 S from the previous MDL calculation to Glaser, J.A., Foerst, D.L., McKee, G.D., compute the F ratio. Quave, S.A., and Budde, W.L., ‘‘Trace Anal- 2 ysis for Wastewaters,’’ Environmental S Science and Technology, 15, 1426 (1981). if A < 305. 2 TABLE OF STUDENTS’ T VALUES AT THE 99 SB PERCENT CONFIDENCE LEVEL then compute the pooled standard deviation Degrees by the following equation: of free- t (n¥1, 1¥a = Number of replicates dom .99) (n¥1) ⎡ 2 2 ⎤05. ⎢ 66SSA+ B ⎥ 7 ...... 6 3.143 = 8 ...... 7 2.998 Spooled ⎢ ⎥ ⎢ ⎥ 9 ...... 8 2.896 ⎣ 12 ⎦ 10 ...... 9 2.821 11 ...... 10 2.764 16 ...... 15 2.602 2 S 21 ...... 20 2.528 if A > 305., 26 ...... 25 2.485 2 31 ...... 30 2.457 S 61 ...... 60 2.390 B 2.326 respike at the last calculated MDL and process the samples through the procedure start- [53 FR 9186, Mar. 21, 1988] ing with Step 4.

(d) Use the Spooled as calculated in 7b to compute the final MDL according to the fol- PART 426—GLASS MANUFAC- lowing equation: TURING POINT SOURCE CAT- MDL = 2.681 (Spooled) EGORY where 2.681 is equal to t (12, 1 ¥a = .99) (e) The 95 percent confidence limits for Subpart A—Insulation Fiberglass MDL derived in 7c are computed according to Subcategory the following equations derived from per- centiles of the chi squared over degrees of Sec. freedom distribution. 426.10 Applicability; description of the insu- MDLLCL = 0.72 MDL lation fiberglass subcategory. MDLUCL = 1.65 MDL 426.11 Specialized definitions. where LCL and UCL are the lower and upper 426.12 Effluent limitations guidelines rep- 95 percent confidence limits respectively resenting the degree of effluent reduction based on 14 aliquots. attainable by the application of the best practicable control technology currently Reporting available. 426.13 Effluent limitations guidelines rep- The analytical method used must be spe- resenting the degree of effluent reduction cifically identified by number or title and attainable by the application of the best the MDL for each analyte expressed in the available technology economically appropriate method reporting units. If the achievable. analytical method permits options which af- fect the method detection limit, these condi- 426.14 [Reserved] tions must be specified with the MDL value. 426.15 Standards of performance for new The sample matrix used to determine the sources. MDL must also be identified with the MDL 426.16 Pretreatment standards for new value. Report the mean analyte level with sources. the MDL. If a laboratory standard or a sam- 426.17 Effluent limitations guidelines rep- ple that contained a known amount analyte resenting the degree of effluent reduction was used for this determination, report the attainable by the application of the best mean recovery, and indicate if the MDL de- conventional pollutant control tech- termination was iterated. nology (BCT).

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